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The isotope abundance of cosmogenic K, especially the ratios of cosmogenic 40K/41K, can be used to determine reliable cosmic-ray exposure (CRE) ages for iron meteorites. Despite this potential, there are only very few studies and essentially no new data since the pioneering work by H. Voshage more than 40 years ago. This shortfall is likely due to the immense analytical difficulties encountered when extracting cosmogenic K from iron meteorites with typical concentrations in the range of a few ppb or below. Chemical extraction procedures are very challenging, resulting in large blank contributions that must be subtracted, and do have low yields preventing an efficient separation of K from the Fe matrix. The K extracted from iron meteorites is dominated by native K (non-cosmogenic K from the sample), includes K from terrestrial contamination, and only a tiny amount is of cosmogenic origin. In order to separate K from iron meteorites a physical extraction technique was developed that involves extraction of K from molten iron meteorites. In this set-up, terrestrial and native K can be partly separated from cosmogenic K by sophisticated pre-heating and extraction techniques. Sample K is ion-optically collected on a rhenium filament. The filaments are then used as evaporation filaments in a double filament set-up of a Triton Plus Thermal-Ionization Mass Spectrometer (TIMS). Though, cosmogenic K is detectable in all samples, the measured isotope ratios are always close to terrestrial, indicating that the majority of the measured 39K and 41K is from K with almost terrestrial isotope composition. The measured 40K signal is dominantly of cosmogenic origin. The K background is either native K from the sample or terrestrial contamination. The measurements are compromised by unstable signals, i.e., by large fluctuations of the ion currents and/or large variations in the isotope ratios during the course of a single run, sometimes even with fractionation reversals. Such difficulties are likely due to the fact that the K ions are implanted into the filament rather than deposited onto the surface. In addition, parts of the filaments are covered with condensed iron, also affecting the signal stability. Despite these analytical challenges, clear cosmogenic signals were detected in almost all studied iron meteorites and cosmogenic 40K/41K ratios could be determined. However, the data quality is not yet sufficient for precise K isotope studies and for calculating reliable 40K/41K CRE ages for iron meteorites. [ABSTRACT FROM AUTHOR]

Quantifying Earth's surface denudation rates is crucial for estimating sediment flux and its role in regulating global climate change. The inability of in-situ cosmogenic 10Be in to quantify denudation rates in quartz–free environment has prompted the need for a new proxy–the ratio of meteoric 10Be met to mineral-weathered 9Be in reactive phase (precipitated in or adsorbed onto secondary minerals). This study utilized 10Be in –26Al in , 10Be met /9Be, and major element analyses of reactive and mineral phases of bedload sediments to infer basin-wide denudation rates and sediment recycling (reworking of deeply buried sediments) in the Three River Source Region (TRSR) of the central Tibetan Plateau. Results from 10Be in -26Al in analysis of bedload sediments and bedrock samples (quartz grain, 250–500 μm) suggest that the sediments underwent burial events since at least 0.54 ± 0.16 million years ago. Combining paleoclimate records in the central Tibetan Plateau, we interpret the "Great Burial" as most likely the result of climate-controlled deglaciation and denudation at the termination of Naynayxungla glaciation during the MIS 13–15 period. This event marks the first widespread deglaciation on the Tibetan Plateau. The 10Be in -26Al in derived paleo–denudation rates range from 4.2 - 0.8 + 0.9 to 151 - 32 + 37 mm/kyr, consistent with previous 10Be in –derived modern denudation rates of 10–117 mm/kyr in TRSR. These rates show a moderate positive correlation with regional topography, particularly channel steepness, indicating a decrease in both relief and denudation rates from lower to upper streams. This spatial discrepancy is likely due to enhanced river headward incision and active neotectonic activities in the southeast. Denudation rates derived from the 10Be met /9Be proxy range from 13 to 248 mm/kyr, alongside a chemical weathering intensity ranging from 43 % to 67 %. These denudation rates are strongly correlated with, but about 1.5 times higher than, the 10Be in –26Al in derived paleo–denudation rates from the same watershed. This suggests that the 10Be met /9Be extracted from fine grains (<64 μm) may reflect a different sediment recycling pattern compared to 10Be in –26Al in in quartz sediments. Alternatively, the 10Be met /9Be ratio could indicate a mixture of carbonate rock with a high denudation rate and silicate rock with a lower denudation rate, whereas 10Be in –26Al in reflects a single silicate denudation signal. [ABSTRACT FROM AUTHOR]

Moraine complexes formed by multiple glaciations are well-preserved in the Mount Geladandong area, the largest center of current glaciation in the Tanggula Mountains in western China. Studies of these glacial landforms provide insights into past glacier changes and contribute to understanding palaeoclimate and palaeoenvironment in the central Tibetan Plateau (TP). Here we report on 10Be surface exposure dating of thirteen rock samples collected from a sequence of glacial landforms associated with the Gangjiaquba Glacier. Based on the dating results, historical records (topographical maps) and morphological relationships, clear Little Ice Age (LIA) landforms are identified, and other landforms are tentatively assigned Neoglacial and global Last Glacial Maximum (LGM G) ages. Dating results for samples from modern glacial landforms demonstrate that the boulders were not affected by nuclide inheritance, and that 10Be surface exposure dating may be used to constrain glacier fluctuations during the past century in high-altitude areas that have high 10Be production rates. A comparison of the ages of a glacially polished surface and adjacent glacial deposits indicates that subglacial erosion by abrasion of the rock surface was insufficient to remove cosmogenic nuclide inventories. Thus the apparent exposure age on the polished surface includes inheritance and over-estimates the actual age for the exposure of this surface. Samples from hummocky moraine have wide age spreads, indicating long-lasting surface instability after deposition of this landform. Successive reduction in glacial extent in the Mount Geladandong area since the LGM G reflects temperature and precipitation changes over this timeframe in the central TP, with climate forcing for glacial advances correlated with cooling signals in the North Atlantic that may have been transmitted to this area by the westerlies. [ABSTRACT FROM AUTHOR]

10Be is an important isotope for accelerator mass spectrometry (AMS) because of the demand for cosmogenic radionuclide dating methods in the earth science and paleo-sciences community. At the iThemba Laboratory for Accelerator Based Science (iThemba LABS) we implemented full suppression of the interfering isobar 10B using a silicon nitride foil-stack, utilizing the 2+ charge state for high efficiency. We demonstrate the performance of this newly established AMS system using standards and test samples. We further present the results of an inter-comparison between iThemba LABS and the Center for Accelerator Mass Spectrometry/Lawrence Livermore National Laboratory, on AMS samples prepared from purified quartz at the University of Vermont. The results for 10Be from the laboratories are in close agreement, fully consistent with cross-calibration between them. AMS results for 26Al are in similarly good agreement, demonstrating the performance and accuracy of iThemba LABS for the most commonly measured in situ produced cosmogenic nuclides. [ABSTRACT FROM AUTHOR]

In situ 14C surface exposure dating is a powerful tool for understanding the Earth's surface processes during the late Quaternary. This study developed an in situ 14C extraction system that heats samples to 1650 °C to extract in situ 14C from quartz. The initial experiments showed a high blank level (1.80 × 107 14C atoms) and low extraction efficiency (5.36%). Each procedural step required a blank test to understand the cause of the high background, and the results identified several components of the extraction system as sources of 14C contamination. After improving the apparatus design, the new system showed a sufficiently low blank level (5.32 × 104 14C atoms). The extraction efficiency ranged from 111% to 127% with this system. These results show that the system is capable of extracting in situ 14C from quartz for surface exposure dating. [ABSTRACT FROM AUTHOR]

Lake Pumoyum Co is located at the south Tibetan Plateau (28°34′N, 90°24′E; ∼5030 m asl; lake surface area 281 km2; present maximum water depth ∼ 65 m). On the northeastern shore of the Lake Pumoyum Co, rock samples (quartzose arenite) were obtained from four areas at different altitudes (T1, ∼5060–5070 m asl; T2, ∼5120 m asl; T3, ∼5160–5170 m asl; T4, ∼5190 m asl). In this study, 10Be/9Be ratios of the quartz in the rock samples were measured by a 5.0 MV AMS system (JAEA-AMS-TONO-5MV; 15SDH-2, National Electrostatics Corporation) at Tono Geoscience Center, Japan Atomic Energy Agency. The 10Be concentrations of the quartz in the rock samples ranged from 3.78 to 10.8 × 106 atoms/g. The calculated minimum 10Be exposure ages and maximum erosion rates ranged from ∼ 41 ka to ∼ 247 ka and from ∼ 4.8 m/Myr to ∼ 14.2 m/Myr, respectively. Relatively young 10Be exposure ages (∼41 ka) were observed in the T4 (∼5190 m asl). Furthermore, the 10Be exposure ages became older from ∼ 41 ka to ∼ 247 ka with decreasing altitude on the northeastern shore of the Lake Pumoyum Co (from ∼ 5190 m asl to ∼ 5060 m asl). Although further geomorphological and chronological researches are needed to understand factors controlling the 10Be exposure ages and erosion rates, the trend in this study may be caused by 1) tectonic activity, 2) retreat of regional alpine glacier or 3) downward migrate of rocks on the area. [ABSTRACT FROM AUTHOR]

• Ages of uplifted marine terraces in western Japan are determined. • Tephrochronology based age determinations confirm the age of TCN derived terraces. • Combined multi-nuclides and depth profile cosmogenic radiometric dating is effective. The southern coasts of Shikoku Island and the Kii Peninsula are located along the Nankai Trough where the Philippine Sea Plate is subducting under the Eurasian plate in Japan. Relatively well-preserved marine terraces along the coast, with elevations ranging between ca. 50 and 100 m, are suitable counterparts to reconstruct the uplift history of the southwestern coast of Japan due to the unique tectonic setting. In this study, we attempt to determine the age of the marine terraces by employing in-situ terrestrial cosmogenic radionuclides (TCN), 10Be and 26Al. TCN depth profiles provide information on the timing of terrace formation. General agreement between our TCN chronology and the existing tephrochronology show that the TCN method can be applicable to a mid-latitude coastal setting where erosion must also be considered. Thus, measuring TCN on uplifted terraces around Japan can be a promising technique for clarifying uplift rates and the seismic history of the region. [ABSTRACT FROM AUTHOR]

The University of Wollongong (UOW) cosmogenic 10Be and 26Al sample preparation laboratory has been in operation since the start of 2017. As primarily a feeder laboratory to ANSTO's Centre for Accelerator Science, our sample preparation procedures have been optimised with consideration to the setup of ANSTO's 6MV SIRIUS accelerator, and aim to achieve a balance between sample throughput as well as Be and Al target purity. A comparatively small number of samples (n = 68) have also been prepared for measurement at the Australian National University 14UD accelerator. 10Be/9Be ratios of procedural blanks measured on SIRIUS have fluctuated over time with the median for the year 2017 being 5.16 × 10−16 (IQR = 4.11 × 10−16 to 7.16 × 10−16, n = 18), increasing to 1.62 × 10−15 (IQR = 1.05 × 10−15 to 2.17 × 10−15, n = 31) for 2018 and 2019, a period coinciding with elevated boron levels in our samples, and finally decreasing to 1.15 × 10−15 (IQR = 8.63 × 10−16 to 1.60 × 10−15, n = 34) for 2020 and 2021. In contrast, 26Al/27Al ratios of procedural blanks measured on SIRIUS have shown a slight but continuous improvement over time with the median for 2017 of 1.70 × 10−15 (IQR = 8.19 × 10−16 to 5.25 × 10−15, n = 12) decreasing to 1.07 × 10−15 (IQR = 8.5 × 10−16 to 1.53 × 10−15, n = 13) for 2021. Median 10Be/9Be relative uncertainty of procedural blanks analysed on SIRIUS is 18 % (IQR = 15 % to 22 %; n = 86) whereas the median 26Al/27Al relative uncertainty of procedural blanks is higher at 60 % (IQR = 41 % to 100 %; n = 56), statistic resulting from most blanks yielding low 26Al counts (median = 2; IQR = 1–4.5). Average 9BeO− output relative to standard is between ∼ 70 % – 80 % for samples analysed on SIRIUS (n = 895) and ∼ 130 % for samples analysed at ANU (n = 68). 27Al− output relative to standard is lower for samples pressed into cathodes at UOW (∼60 %, n = 432) and analysed on SIRIUS than for those pressed at ANSTO (∼90 %, n = 119). Average 27Al− output relative to standard for samples analysed at ANU is ∼ 80 % (n = 62). 10Be and 26Al measurements of various laboratory intercomparison materials prepared at UOW between 2017 and 2022 yield results in agreement with consensus values confirming that our chemistry procedures are robust and in line with those elsewhere. [ABSTRACT FROM AUTHOR]

Increasing interest in applications where 10Be concentrations are low leads to a challenge in measurement and how to minimise the losses in accelerator mass spectrometry. Selecting a 2+ charge state for analysis instead of 3+ after the accelerator offers a potential gain by a factor of 2 in total measurement efficiency. Benchmarking the 10Be 2 + SiN foil stack ion detection against well-established 10Be 3 + absorber cell technique, using a set of samples with artificially elevated B concentrations, we demonstrate that there is no clear benefit in using 20.3 MeV 10Be 3 + ions for 10Be measurement. Equal suppression against 10B derived interferences can be achieved with 10Be 2 + and 10Be 3 + ions. [ABSTRACT FROM AUTHOR]

The Larsemann Hills, near Prydz Bay is a key region to understand past glacial dynamics in East Antarctica. However, multi-proxy dating constraints for this area indicate an uncertain chronology for deglaciation history during the Last Glacial Period (LGP). In this paper, we report two 26Al exposure ages and eighteen 10Be exposure ages for bedrock samples to better understand past glacial histories. The minimum exposure ages range from 82.84 ± 4.67 ka to 15.1 ± 1.95 ka corresponding to Marine Isotope Stages (MIS) 5–2, and fourteen of these samples date from before the global Last Glacial Maximum (c. 19–26.5 ka). Analysis of 10Be and 26Al concentrations implies a complex deglaciation history, and surface lowering of bedrock may have caused systematic age underestimation. Further comparisons between two adjacent regions in the Mirror Peninsula reveal two major deglaciations involving the Lambert Glacier / Amery Ice Shelf System dated at 61.78 ka to 82.84 ka and 21.98 ka to 49.5 ka during the LGP. • We present new evidence for studying glacial history of Larsemann Hills, Antarctica. • Cosmogenic nuclides 10Be and 26Al dating method is applied for better analysis. • Two major deglaciation events occurred regionally within MIS 2–3 and MIS 4–5. • The exposure age and elevation show a highly significant positive correlation. • Multi-proxy and adjacent evidence are summarized and compared with this study. [ABSTRACT FROM AUTHOR]

Determining slip rates is essential for assessing earthquake hazards and understanding their recurrence intervals. However, in regions characterized by slow deformation, the long intervals between seismic events present challenges in understanding the long-term seismic behavior. This study focused on the Yangsan Fault (YF) on the Korean Peninsula, which is a major active fault in a slowly deforming area. We identified paleo-surface ruptures and validated stratigraphic evidence of paleo-earthquakes by geomorphological analyses and trench surveys along the YF. Landform restoration analyses indicate a lateral offset of ~320 m, which is supported by downstream changes in gravel composition in channels that cross the YF. Our investigation into the notable changes in gravel composition within channels forming in the alluvial fan revealed sediments with compositions unlikely to originate from the current topography. Observations of the sediment composition in channels within the alluvial fan, flowing from east to west, suggest a dextral slip sense focused around the YF. The minimum slip rate for the lateral offset was calculated to be 0.38–0.57 mm/yr using a burial age of ca. 698 ka for a gravel deposit exposed in a trench wall. The results show the importance of using diverse approaches to mitigate methodological uncertainties in measuring fault displacements and ages, particularly when determining the long-term slip rate in intraplate settings. • Deriving long-term slip rates of strike-slip faults in intraplate environments • Estimating offset using geomorphic offset markers and verifying with provenance analysis of sediments • Age dating using cosmogenic nuclides • Discussing differences with various methods for estimating offset • Discussing various factors that may cause differences in slip rates [ABSTRACT FROM AUTHOR]

[Display omitted] • Geomorphic indices indicate stronger tectonic activity in the central Three Rivers Region compared to surrounding areas. • Geomorphic characteristics are related to erosion patterns across various spatio-temporal scales. • Intense erosion has halted the expansion of the southeastern Tibetan Plateau despite ongoing extrusion. The growth and expansion of the southeastern Tibetan Plateau remain contentious. Positioned as one of the regions characterized by the most robust tectonic activities on the plateau, the southeastern edge provides a distinctive setting for investigating plateau uplift and landform evolution. This study focuses on the southeastern margin of the plateau in the Three Rivers Region, conducting comprehensive analyses of slope, relief, hypsometric integral (HI), and channel steepness index (k sn ). We use this new dataset to highlight the more significant role of tectonic activities in shaping the landform compared to climate and lithology. By examining the spatiotemporal characteristics of long-term and short-term rock exhumation rates, derived from low-temperature thermochronology and cosmogenic nuclide 10Be analysis, we establish a correlation between erosion rates and k sn , slope, and terrain undulation. Integrating this information with geophysical evidence and GPS data, we support the model for the expansion of the southeastern edge—the steady-state terrain crustal flow model. According to this model, there is an equilibrium achieved between rock uplift and surface erosion on the southeastern edge of the Tibetan Plateau. Despite ongoing southeastward extrusion of plateau material, the overall plateau morphology remains unaltered due to intense erosion along the plateau's edge. Consequently, the large-scale topographic expansion of the southeastern Tibetan Plateau has effectively halted. [ABSTRACT FROM AUTHOR]

The formally named SP lava flow is a quartz-, olivine- and pyroxene-bearing basalt flow that is preserved in the desert climate of northern Arizona, USA. The flow has an 40Ar/39Ar age of 72 ± 4 ka (2σ) and has undergone negligible erosion and/or burial, making its surface an ideal site for direct calibration of cosmogenic nuclide production rates. Production rates for cosmogenic 3He (3He c) and 21Ne (21Ne c) have been determined from SP flow olivine and pyroxene in this study. The error-weighted mean, sea-level, high latitude (SLHL) total reference production rates of 3He in olivine and pyroxene have identical values of 135 ± 8 at/g/yr (2 σ x ‾ ; standard error) using time-independent Lal (1991)/Stone (2000) (St) scaling factors. These production rates decrease to identical values of 130 ± 8 at/g/yr (2 σ x ‾ ; standard error) when 3He measurements are standardized to the CRONUS-P pyroxene standard. The St- scaled, error-weighted mean, total reference production rates of 21Ne in olivine and pyroxene are 48.4 ± 2.9 at/g/yr and 26.5 ± 1.7 at/g/yr (2 σ x ‾ ; standard error), respectively, increasing to 49.3 ± 3.0 at/g/yr and 27.0 ± 1.7 at/g/yr (2 σ x ‾ ; standard error), respectively, when standardized to the CREU-1 quartz standard. 3He and 21Ne production rates (St) overlap within 2σ uncertainty with other St -scaled production rates in the literature. SLHL 3He and 21Ne production rates in SP flow olivine and pyroxene are nominally lower if time- dependent Lm and Sa scaling factors are used. Olivine and pyroxene both have identical, error-weighted mean SLHL production rates of 127 ± 8 at/g/yr (2 σ x ‾ ; standard error) using Lm scaling factors and CRONUS-P standardized 3He measurements. These production rates decrease to identical values of 110 ± 7 at/g/yr (2 σ x ‾ ; standard error) for olivine and pyroxene when using Sa scaling factors. The Lm -scaled, error-weighted mean, total reference production rates of 21Ne in olivine and pyroxene are 48.1 ± 2.8 at/g/yr and 26.4 ± 1.7 at/g/yr (2 σ x ‾ ; standard error), respectively, when standardized to the CREU-1 quartz standard. The error weighted mean, local 21Ne/3He production rate ratio in olivine is 0.358 ± 0.009 (2 σ x ‾ ; standard error), which increases to 0.378 ± 0.012 when using CREU-1 standardized 21Ne production rates and CRONUS-P standardized 3He production rates. The error weighted mean, local 21Ne/3He production rate ratio in pyroxene is 0.197 ± 0.006, or 0.208 ± 0.008 when 21Ne and 3He are standardized to CREU-1 and CRONUS-P, respectively. The updated, CREU-1 standardized 21Ne c rate (St) in SPICE quartz is 16.5 ± 1.1 at/g/yr. Production of 21Ne in coexisting SPICE olivine (ol), pyroxene (px), and quartz (qz) (standardized to CREU-1; Fenton et al., 2019; this study) yields error-weighted mean, local production rate ratios of 3.00 ± 0.13 (2 σ x ‾ ) and 1.64 ± 0.08 (2 σ x ‾ ) for 21Ne ol /21Ne qz and 21Ne px /21Ne qz , respectively. This study suggests that production rates of 3He and 21Ne in SPICE olivine and pyroxene agree well with St- and Lm- scaled global mean production rates in the literature. It also indicates that CRONUS-P and CREU-1 standardizations yield production rates in even stronger agreement with these global mean rates. • 3He c and 21Ne c production rates (St) in ol are 135 ± 8 and 48.4 ± 2.9 at/g/yr. • 3He c and 21Ne c production rates (St) in px are 135 ± 8 and 26.5 ± 1.7 at/g/yr. • CRONUS-P standardized 3He c rate (St) in both ol and px is 130 ± 8 at/g/yr. • CREU-1 standardized ol and px 21Ne c rates (St) are 49.3 ± 3.0 and 27.0 ± 1.7 at/g/yr. • CREU-1 standardized 21Ne c rate (St) in quartz is 16.5 ± 1.1 at/g/yr. [ABSTRACT FROM AUTHOR]

Understanding inter-aquifer connectivity or leakage of greenhouse gases and groundwater to aquifers overlying gas reservoirs is important for environmental protection and social licence to operate. Australia's Great Artesian Basin (GAB) is the largest artesian groundwater system in the world with groundwater extracted for agriculture, livestock, mines, energy, private or town water supply. Microbial coal seam gas (CSG) and production water are also extracted from the GAB. Here a range of groundwater tracers is used to investigate the potential for gas and groundwater connectivity between the CSG reservoir and aquifers. The GAB aquifer and alluvium contained a range of methane concentrations (0.001 to 2100 mg/L) that exhibit an increase with depth and δ13C-CH 4. Aquifer and alluvium groundwater 87Sr/86Sr were in the range 0.7042 to 0.7082. CSG production waters however had non-radiogenic, distinctive 87Sr/86Sr signatures <0.7036, indicating a lack of significant groundwater leakage. One gassy aquifer bore with 160 mg/L methane conversely has 87Sr/86Sr, δ13C-CH 4 , δ2H-CH 4 and δ13C-DIC values overlapping the CSG waters. In several aquifers δ34S-SO 4 and δ18O-SO 4 are sourced from windblown surface salts of inland Australian playa lakes in recharge waters. Bacterial sulphate reduction is additionally occurring in a regional aquifer. Cosmogenic isotopes and tritium show recent recharge and mixing with older groundwaters in several shallow aquifers. Groundwater and gas signatures indicate that leakage of groundwater and methane from the CSG reservoir was not occurring in the majority of areas investigated here. Methane was consistent with in situ generation in shallow GAB aquifers by primary microbial CO 2 reduction or acetate fermentation. Connectivity of one alluvial bore and the underlying GAB aquifer could not be completely ruled out. Separately, one gassy Springbok GAB aquifer bore is either connected to the underlying CSG gas reservoir, or has in situ secondary microbial CO 2 reduction producing methane from interbedded coal within the aquifer. This study is relevant to other basins in Australia and internationally where gas is observed in aquifers that overly conventional, unconventional or coal seam gas reservoirs. [Display omitted] • Coal seam gas region multi-isotope GAB aquifer groundwater gas connectivity study. • CSG reservoir non-radiogenic distinctive 87Sr/86Sr and gas isotope vs GAB aquifers, alluvium. • δ34S, δ18O-SO 4 source: surface salts in recharge waters, bacterial SO 4 reduction in one aquifer. • Possible gas leakage into one gassy bore. Mixing of modern waters in shallow aquifers. • Signatures support dis-connectivity of the CSG reservoir with majority aquifer bores. [ABSTRACT FROM AUTHOR]

The Afar region constitutes the diffuse triple junction adjoining the Red Sea, Gulf of Aden, and Main Ethiopian Rifts. Extension in the Afar is distributed between on-axis, magmatic crustal spreading, and off-axis, amagmatic extension, such as in Dobe graben. The timing of initiation and development of these amagmatic grabens is key to understanding the final stages of continental extension/breakup in central Afar. All major graben-bounding faults in central Afar cut through the Quaternary Afar Stratoid Series, constraining the ages of initiation to younger than approximately 1 million years. The Afar Stratoid Series presents a widespread thick lava unit that smoothed and infilled the topography created by the prior 30 Ma of deformation. The ∼1 Ma top surface of the Afar Stratoid Series serves as a regional marker predating most Quaternary deformation. The initiation of a particular fault (or location along a graben-bounding fault) begins a process of local lowering of base level – this is recorded in the landscape as a knickpoint that incises the paleo drainage in the footwalls of the grabens, connecting it to the basin floor with a deep canyon. The rate at which knickpoints retreat upstream permits a space-for-time approach to assessing initiation. This study develops and applies a landscape evolution model to estimate relative maturity and age of drainage basins by measuring the long profile response to tectonic forcings over intermediate timescales in central Afar. This is applied under the assumption that faulting postdates Afar Stratoid Series emplacement. The model is calibrated by analysis of stream longitudinal profiles and terrestrial cosmogenic nuclide (TCN) analysis of samples collected in the field. Longitudinal stream valley profiles are mapped through remote sensing and photogrammetry, and TCN concentrations are assessed to calculate the uplift rate along the graben-bounding faults. Results indicate that faulting of Dobe Graben in the central Afar initiated in the southeast and propagated to the northwest. Along the southern margin of Dobe Graben, ages of 503 ± 116 ka were calculated for fault initiation at Hann Canyon in the southeast, and 339 ± 80 ka at Ishyilu Canyon to the northwest. These timing constraints have implications for competing tectonics models for central Afar. The general approach developed for modeling knickpoint retreat has broader utility beyond Afar, allowing for application to extensional tectonic regimes elsewhere where similar geological and surface constraints exist. • Knickpoint retreat within two major canyons along a single graben-bounding fault in central Afar was modeled. • The rate of knickpoint retreat was calibrated using in-situ cosmogenic nuclide dating of abandoned terraces in the canyons. • Timing of knickpoint initiation displays distinct ages for each canyon. • This methodology can be extended across the rest of central Afar that is covered by similar flood basalts. [ABSTRACT FROM AUTHOR]

Mineral exploration often relies on sedimentary indicators as first signs of a potential nearby mineralization in bedrock. The transportation of sediment by glacial and fluvial processes introduces uncertainty into the tracing of potential source areas of the sediment. This is particularly challenging in areas where glacial erosion has been weak, resulting in reworking of sediments and multiple directions of transportation. In this study we explore the use of Terrestrial Cosmogenic Nuclides (TCN) alongside conventional mineral exploration methods to better link indicators with their potential source areas. The study focuses on a mineral exploration project site in northern Finland in a region with stratigraphic evidence of multiple glaciations. The project targets the source of discovered Au mineralized erratic boulders that have been deposited atop the most recent till unit. The superposition suggests transportation in the latest glacial event. However, the 10Be (35.9 ± 1.3 and 30.3 ± 1.1 ka) and 26Al TCN ages analyzed from the mineralized erratics precede the latest glacial event, suggesting the possibility of multiple stages of transportation. The local bedrock TCN inventories (48.9 ± 1.9 and 85.3 ± 2.8 ka) are well preserved, suggestive of weak glacial erosion and therefore short recent transportation distances for the mineralized erratics. By combining the TCN interpretation and historical ice flow directions derived from the till stratigraphy, we suggest a nearby source locating NNW of the dated erratics. We find that TCN dating can limit some of the transportation related uncertainties in glaciated terrain. Through the analysis of TCN inventories from bedrock and boulders it is possible to characterize glacial erosion and boulder transportation, and to identify repeated exposure events, i.e., the possibility of multi-staged transportation. The method benefits from combined use of stratigraphic investigations that can identify both the local transportation directions and local glacial coverage history. TCN sampling has a minimal environmental impact, can be used in remote areas and can provide information about the transport history already in the early stages of exploration. Although the analysis is time consuming, the survey is light to conduct and informative even with a small number of samples. • The TCN method can identify the possibility of multiple boulder transport events • The measured bedrock exposure history can be used to infer past erosion intensity • Combined these can help estimate transportation distances and source areas • The method can be used early in exploration to estimate transportation complexity • Our TCN results suggest a nearby source for the studied Au mineralized erratics [ABSTRACT FROM AUTHOR]

Shore platforms, essential for coastal analysis and management, are poorly understood in terms of their long-term evolution, particularly regarding coastal cliff retreat rates and trends, despite their common presence in rocky coastlines. Rock coasts constitute fully erosional environments, yet long-term rates and trends of coastal cliff retreat remain poorly understood. This study adds to the limited number of studies that use cosmogenic isotopes to reconstruct millennial-scale cliff erosion. Cosmogenic 10Be concentrations were measured in 16 rock samples collected across an active 31 m wide granitic Jangsa shore platform in eastern Korea. A geometry-based inverse numerical model was used to simulate 10Be concentrations for various cliff retreat modes, relative sea level curves, and platform downwearing models. The model results were combined with measured concentrations to find the most likely scenario for coastal evolution. Our findings reveal that the shore platform has widened through time and is entirely formed during the Holocene, unlike the previous cosmogenic study in western Korea that attributed the formation of shore platforms to former interglacial periods. The results suggest acceleration in cliff retreat rate from 1.4 mm yr−1 at 7.4 kyr BP to 7.0 mm yr−1 at present. Accelerating cliff erosion may pose a threat to coastal communities, particularly in the context of observed and predicted anthropogenic sea level rise. • Numerical model simulates cosmogenic 10Be distribution across a shore platform in eastern Korea. • The granitic Jangsa shore platform was formed entirely during the Holocene. • Cliff retreat rate has accelerated 1.4 mm yr−1 at 7.4 kyr BP to 7.0 mm yr−1 at present. • Shore platform has widened by maintaining fixed seaward edge position and decreasing the slope. • First study to quantify millennial-scale cliff retreat rates on a granitic shore platform. [ABSTRACT FROM AUTHOR]

Quantitatively characterizing the geometry, kinematics, and deformation rate of fold-thrust belts in intermontane basins is the key to understanding strain partitioning within the Tian Shan range. This work focuses on the Bayin anticline in the Youludusi Basin, a typical intermontane basin located within the eastern Tian Shan. The Kaidu River cuts through the Bayin anticline and has developed three levels of terraces (T 1 –T 3) across the structure. By using cosmogenic nuclide and optically stimulated luminescence dating methods, the formation ages of terraces T 1 and T 3 are constrained to 11.54 ± 0.55 ka and 42 + 7.0/−7.1 ka, respectively. When applying a listric thrust fault model to the Bayin anticline and using terraces as references, the vertical displacements are estimated to be 16.45 + 6.46/−3.19 m (T 1), 32.08 + 12.85/−6.19 m (T 2), and 95.93 + 38.94/−18.6 m (T 3), and the shortening amounts are 10.56 + 8.33/−5.04 m (T 1), 20.46 + 16.68/−9.64 m (T 2), and 61.24 + 50.22/−28.93 m (T 3). Based on this listric thrust fault model and terrace T 1 –T 3 ages, the rate of fault slip controlling the growth of the Bayin anticline is determined to be 1.6 ± 1.0 mm/yr, and the crustal shortening rate of the anticline is 1.0 + 0.7/−0.6 mm/yr. The estimated crustal shortening deformation of the Bayin anticline accounts for ∼12 % of the total deformation in the Youludusi Basin. In terms of the entire orogenic belt, the crustal shortening absorbed in the southern, central, and northern parts accounts for 24 %–56 %, 46 %–71 %, and 19 %–74 %, respectively, of the total strain across the eastern Tian Shan. Therefore, we believe that the Eastern Tianshan undergoes uniform deformation. • Constrained the shortening rate of the Bayin anticline in the central Tianshan • Employed fold models to infer the geometrical structure of deep-seated faults • The deep structure of Bayin anticline is controlled by thrust faults. • The shortening rate of Bayin anticline is about ∼1.6 ± 0.2 mm/yr since 42 ka. [ABSTRACT FROM AUTHOR]

Moraine deposits are difficult to date using conventional luminescence techniques, especially such deposits without glaciofluvial sand lenses incorporated within the feature. Recently developed rock surface luminescence burial dating has shown the potential for constraining heterogeneous glacial till sediments. However, the wider applicability of the luminescence dating of cobbles obtained from moraine deposits needs to be tested. Thirty-one buried granite cobbles from different generations of terminal moraines of the last deglaciation moraine series in the source area of the Litang River, eastern Tibetan Plateau, were collected. Eight cosmogenic nuclide 10Be exposure ages were generated from eight boulders obtained from the ridges of two moraines, to provide an external age control. A post-IR 50 IRSL 225 single aliquot regenerative dose (SAR) protocol was applied to measure the luminescence signal from rock slices. The IRSL 50 L n /T n -depth profiles from 23 cobbles showing surface age plateaus (up to 12 mm), indicating that the material was well-bleached prior to deposition. The depth of the bleaching front is variable between individual cobbles from the same deposit. Three distinct methods were employed to observe and correct for any anomalous fading present. We observe age agreement from different cobbles collected from the same moraine deposits, illustrating the reproducibility at our selected locations. The luminescence ages of burial cobbles (15.5 ± 2.1 ka to 20.0 ± 1.6 ka) align with geomorphic relationships and 10Be exposure ages. Particularly, the age of cobbles from one of the moraines (20.0 ± 1.6 ka) is consistent with independent 10Be exposure ages (18.6 ± 1.2 ka) of boulders from the same moraine. This study demonstrates the applicability of the luminescence dating of moraine deposits, using cobbles, and provides deeper insights of the last deglaciation in the eastern Tibetan Plateau. • Rock surface luminescence dating of the last deglaciation moraines from east Tibet. • 74% of L n /T n -depth profiles from 31 granite cobbles indicate well bleaching. • Post-IR 50 IRSL 225 protocol to measure D e and three methods to correct fading. • NLS corrected IRSL 50 ages agree with independent 10Be exposure age control. [ABSTRACT FROM AUTHOR]

Temperate glaciers are very sensitive to changes in the global climate system and provide an excellent opportunity to obtain information on the timing and magnitude of palaeoclimatic changes. Numerous studies in the Mediterranean mountains indicate alternating glacial advance and retreat episodes during the last glacial cycle (110.8 ka to 11.7 ka ago). However, glacial chronology is often restricted to the global Last Glacial Maximum (LGM), and records covering the remainder of the last glacial cycle are less well-known in the eastern Mediterranean region. Here, we present a continuous chronology of glacial stages in the east Mediterranean based on cosmogenic 36Cl terrestrial cosmogenic nuclides (TCN) in glacial landforms. We present 105 36Cl ages (43 new and 62 recalculated from previously published studies) from the moraine, landslide, glacial outwash boulders, and limestone bedrock from Mt. Aladağlar (37°8′N, 35°2′E) in the central Taurus Mountains of Southern Türkiye. Three local icefields (Yedigöller, Körmenlik, and Akçay icefields, covering 20 km2, 8 km2, and 7 km2, respectively, and >3000 m above sea level (asl)) occupied the summits in the past. The bedrock ages obtained from the uppermost parts of the Yedigöller Plateau indicate that the peaks (>3400 m, asl) have been ice-free since about 67 ka. Several glacier tongues descended from the icefields through eight main glacial valleys (three on the western and five on the eastern side). The outwash fan along the SW front of Mt. Aladağlar represents the oldest (about 136 ka) glacial deposits developed during the previous glacial cycle. Four other outwash fans yielded ages that range from about 97 ka to 65 ka, indicating deposition during the last cycle. On the western side, the oldest moraine ages (about 46 ka and 38 ka) from two valleys show pre-LGM advances that could be considered the maximum extent of local glaciers. Intriguingly, global LGM moraines (about 23-19 ka) are relatively small and preserved only at high elevations (>2450 m asl). Recalculated ages of seven consecutive moraines in the longest (17.2 km) and the deepest valley on the eastern side indicate Late Glacial (about 15 ka) to Early Holocene (about 12 ka) deglaciation. Several small moraines also show deglaciation (about 12-10 ka) corresponding to the Younger Dryas and the onset of the Holocene. The ages obtained from Mt. Aladağlar indicate a complete range of glacial conditions during pre-LGM, global LGM, Late Glacial, Younger Dryas, and Early Holocene in the eastern Mediterranean. • A continuous last glacial cycle 36Cl glacial chronology from Mt Aladağlar, Türkiye. • 105 moraine, landslide, glacial outwash boulders and limestone bedrock ages. • Three local icefields (>3000 m) and eight main glacial valleys. • Oldest moraines (46 ka) indicate the maximum extent of local glaciers. • Last Glacial Maximum, Late Glacial, Younger Dryas, and Early Holocene glaciers. [ABSTRACT FROM AUTHOR]

In-situ produced cosmogenic nuclide sample preparation and analysis is a complicated, multi-step process with numerous possible sources of error, many of which have not been robustly quantified. Here, we use a liquid reference material (UVM-A) to test whether the analytic precision associated with individual isotopic ratios (n = 96) measured at two Accelerator Mass Spectrometry facilities (Lawrence Livermore National Laboratory and Purdue Rare Isotope Measurement Laboratory) accurately represents the range of values determined for aliquots prepared in a single laboratory over a period of five years. We find that 10Be/9Be ratios measured at the different accelerator facilities (n = 26 and n = 70) have statistically indistinguishable central tendencies, matching to within 0.1 %. Based on this large dataset, we suggest preliminary consensus values for UVM-A of 1.45 ± 0.06 x 10−13 for 10Be/9Be (mean, one standard deviation, n = 96) and 4.47 ± 0.22 x 10−13 for 26Al/27Al (mean, one standard deviation, n = 27). For both 10Be/9Be and 26Al/27Al, the relative standard deviations of the measured ratios are similar to the reported analytic uncertainties of sample measurement, suggesting that sample preparation introduced little if any additional scatter beyond the uncertainty of isotopic analysis. This dataset demonstrates that robust sample preparation and measurement can generate isotope ratio data reproducible at the level of counting statistics. [ABSTRACT FROM AUTHOR]

• Refined purification method for very-fine sand size quartz. • 35% mass loss is crucial to purify very fine material for cosmochemistry. • Large amounts of aluminium present a larger purification challenge than meteoric 10Be. • Ineffective purification can severely affect exposure age, erosion rate estimates, and ion beam currents. Quartz purification is a necessary and critical step to producing robust and reproducible results in terrestrial cosmogenic nuclide studies. Previous quartz purification work has centred on coarse sample material (1 mm-500 µm) and is anecdotally effective down to ∼250 µm. However, sample material with finer grain sizes are usually discarded. The adapted purification procedure outlined here shows that very-fine-sand sized material (125–63 µm) can be reliably cleaned for use in terrestrial cosmogenic nuclide studies. The results below show that 35% mass loss in very fine-grained quartz is sufficient to remove major elements (Al, Ti, Na, K, Fe, Mg, Ca, Mn,), 9Be, and meteoric 10Be. While other precise analysis (ICP-MS and ICP-OES) can verify sample purity, mass loss is a fast, inexpensive, and easy metric to set a standard by. This work shows that meteoric 10Be is easily removed from very-fine-grained samples while Al takes more effort. [ABSTRACT FROM AUTHOR]

A record of 44Ti activity measured in 20 stony meteorites fallen during CE 1766–2001 was compared to six series of 44Ti activity, calculated from the data on modulation parameter Φ based on cosmogenic isotopes 14C and 10Be. It was shown that both experimental and computed records have appreciable divergences. The secular trends of many model curves are flatter than that of the measured record and the difference in amplitude of the century-scale cycle of Gleissberg is highly significant (p < 5.5 × 10−4). Possible causes of this discrepancy are discussed. The obtained results show that at present the cosmogenic isotope data likely contain mostly qualitative information about the behavior of the cosmic ray flux in the past and not always are suited for quantitative estimations. [ABSTRACT FROM AUTHOR]

During the last deglaciation, collapse of the saddle between the North American Cordilleran and Laurentide ice sheets led to rapid ice-sheet mass loss and separation, with meltwater discharge contributing to deglacial sea-level rise. We directly date ice-sheet separation at the end of the saddle collapse using 64 10Be exposure ages along an ∼1200-km transect of the ice-sheet suture zone. Collapse began in the south by 15.4 ± 0.4 ka and ended by 13.8 ± 0.1 ka at ∼56°N. Ice-sheet model simulations consistent with the 10Be ages find that the saddle collapse contributed 6.2–7.2 m to global mean sea-level rise from ∼15.5 ka to ∼14.0 ka, or approximately one third of global mean sea-level rise over this period. We determine 3.1–3.6 m of the saddle collapse meltwater was released during Meltwater Pulse 1A ∼14.6-14.3 ka, constituting 20–40% of this meltwater pulse's volume. Because the separation of the Cordilleran and Laurentide ice sheets occurred over 1–2 millennia, the associated release of meltwater during the saddle collapse supplied a smaller contribution to the magnitude of Meltwater Pulse 1A than has been recently proposed. • Cordilleran-Laurentide ice-sheet separation began before ∼15.5 ka. • Cordilleran-Laurentide ice-sheet separation ended by ∼13.8 ka. • The 1–2 kyr duration means separation had a modest impact on abrupt sea-level rise. [ABSTRACT FROM AUTHOR]

Inselbergs are isolated rock bodies that develop as a result of differential weathering and erosion advances during topographic etchplain formation. The timing and rate of inselberg growth are key for constraining external controls on landscape evolution, particularly in etching terrains associated with elevated plateaus carved on granitic lithologies, and in tectonically active provinces in tropical climate zones (e.g., Antioqueño Plateau, AP). We applied new morphostratigraphic and geomorphometric analyses, along with 10Be terrestrial cosmogenic nuclide (TCN) measurements, to in situ rock samples from the Peñol de Guatapé Inselberg (PGI), in the AP of the Colombian Andes to address the chronological framework of bornhardt formation in this tropical setting. The PGI is located in a rejuvenated landscape between middle Miocene to late Mio-Pliocene erosion surfaces. Erosion rates inferred from 10Be analyses ranged between ∼0.0024 ± 0.0001 and 0.24 ± 0.0283 mm/yr. This broad range is consistent with the long-term erosion rate of ∼0.04 mm/yr and mid-term erosion rates of 0.01–0.08 mm/yr previously documented for the region using low-temperature thermochronology. Our findings indicate that the PGI emerged as an important landscape feature over a period of ∼0.5–2.0 Myr and has protruded high above the average AP surface since the Pliocene. The new TCN-derived erosion-rate estimates for the AP Inselberg enable us to better understand the role of weathering and erosional processes that controlled the evolution of landscape surfaces during Andean orogenic cycles documented in the region. • El Peñol de Guatapé Inselberg (PGI) is the largest bornhardt in the Antioqueño Plateau (AP). • The (AP) is the most extensive and best-preserved planation surface in the Northern Andes. • The PGI lies in a rejuvenated landscape of the AP between erosion surfaces of middle Miocene to late Mio-Pliocene age. • In situ 10Be concentrations suggest million-year scale erosion rates between 0.0024 and 0.24 mm/yr. • PGI formation occurred during the Pliocene as a result of erosional and tectonic forcing. [ABSTRACT FROM AUTHOR]

Geological storage of gases will be necessary in the push to net zero and the energy transition to reduce carbon emissions to atmosphere. These include CO 2 geological storage in suitable sandstone reservoirs. Understanding groundwater flow, connectivity and hydrogeochemical processes in aquifer and storage systems is vital to prevent risk and protect important water resources, such as the Great Artesian Basin. Here, we provide a 'tool-box' of geochemical assessment methods to provide information on flow patterns through the basin's aquifers (changes in chemistry along flow path), stagnant versus flowing conditions (cosmogenic isotopes and noble gases), inter-aquifer connectivity and seal properties (major ions, Sr and stable isotopes), water quality (major ions and metals) and general assessments on residence times of groundwater (cosmogenic isotopes and noble gases). This information can be used with reservoir and groundwater models to inform on possible changes in the above-mentioned processes and serve as input parameters for CO 2 injection impact modelling. We demonstrate the use and interpretation on an example of a potential CO 2 storage geological sequestration site in the Surat Basin, part of the Great Artesian Basin, and the aquifers that overly the reservoir. The stable water isotopes are depleted compared to average rainfall and most likely indicate greater contributions from monsoonal rain events from the northern monsoonal troughs, where amount and rainout effects lead to the depletion rather than colder recharge climates. This is supported by the modern recharge temperatures from noble gases. Inter-aquifer mixing between the Precipice Sandstone reservoir and the Hutton Sandstone aquifer seems unlikely as the Sr isotope ratios are distinctly different suggesting that the Evergreen Formation is a seal in the locations sampled. Mixing, however, occurs on the edges of the basin, especially in the south-east and east where the Surat Basin transitions into the Clarence-Moreton Basin. Groundwater flow appears to be to the south in the Precipice Sandstone, with a component of flow east to the Clarence-Morton Basin. The cosmogenic isotopes and noble gases strongly indicate very long residence times of groundwater in the central south Precipice Sandstone around a proposed storage site. 14C values below analytical uncertainty, R36Cl ratios at secular equilibrium as well as high He concentrations and high 40Ar/36Ar ratios support the argument that groundwater flow in this area is extremely slow or groundwater is stagnant. The results of this study reflect the geological and hydrogeological complexities of sedimentary basins and that baseline studies, such as this one, are paramount for management strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

Wind-abraded cobbles (ventifacts) and aeolian sand are known from the sandy-gravelly coastal areas of south-western Sweden, especially in association with raised deltas. Ventifacts are recorded on at least two different stratigraphic levels, at some sites atop glaciofluvial sediment, at other sites atop littoral deposits, and in some places at both levels, while aeolian sand usually forms a surficial cover. The formation of ventifacts has usually been coupled to abrasion due to katabatic winds from the retreating ice sheet or with periglacial climate during the Younger Dryas stadial (12.8–11.7 ka). To determine the timing of these deflation events, we have applied a combination of dating methods to ventifacts and associated sediments on top of an ice-contact delta at Veinge, south-western Sweden. Quartz and feldspar luminescence dating as well as portable luminescence profiling has been used for littoral and aeolian sediments over- and underlying deflation surfaces, while rock surface luminescence burial dating and paired 14C–10Be cosmogenic nuclide dating were conducted on ventifacts. The results show that a first deflation event occurred c. 16.5 ka, just after deglaciation and prior to a regional transgression that peaked around 15.7 ka. At 12.4–11.4 ka, during the Younger Dryas stadial, a new set of ventifacts formed on the surface of the exposed littoral sands and gravels. Some wind abrasion also occurred in the early Holocene, but at c. 8.5 ka the surface was covered by aeolian sand, up to 2.5 m thick. The combination of different dating methods have allowed us to draw more informed conclusions on the timing and duration of these wind abrasion/transport events than would have been possible from the use of only single-method dating. It has also made it possible to infer some environmental conditions during deposition. For example, both glaciofluvial and littoral deposits show evidence of incomplete bleaching of the luminescence signal. This suggests short subaerial transport and brief reworking by waves, respectively, though bleaching conditions improved during shore regression. Rock surface burial luminescence profiles reveal that some ventifacts were repeatedly exposed, but that later event(s) were shorter in duration as indicated by quartz-feldspar age comparisons. [Display omitted] • Wind-abraded clasts and aeolian sand occur on an ice-contact delta in SW Sweden. • Three erosional (deflation, abrasion) and one depositional event are recorded. • Luminescence and cosmogenic exposure dating place the events between 17 and 8.5 ka. [ABSTRACT FROM AUTHOR]

The Gulf of Elat-Aqaba (GEA), located in the southern part of the Dead Sea Transform (DST), is one of the most active segments of the Dead Sea fault system. Yet, some fundamental details concerning its evolution in space and time are still not fully understood. To better constrain the tectonic history of this region, we study a succession of alluvial, lacustrine, and fluvial deposits in the north-western edge of the GEA, which belong to the Quaternary Eilot and Garof Fms. The Eilot Fm. represents low-energy shallow freshwater bodies and sabkhas, which predate the development of the deep part of the basin. Later, in response to the subsidence of the basin, the Garof Fm. was deposited in alluvial fans that built up following the increase in the depositional energy. Cosmogenic burial ages combined with magnetostratigraphy show that these Fms. were deposited as early as 3.03 Ma and as late as 1.65 Ma, depending on the applied age model. Considering the present depth of the northern GEA, this age indicates a maximum subsidence rate of the head of the GEA of ∼1.98mm/yr. We suggest that faults along the onshore margin of the deep basin were active during the deposition of the Garof Fm. and subsequently became inactive, while the faulting activity migrated toward the center of the basin. Closed Holocene basins north of the present seashore, such as the Elat and Evrona playas, which may represent a modern analogue to the Plio-Pleistocene morphology, raise the possibility that the GEA head is still propagating northward. • Quaternary sedimentary units in the head of the Gulf of Elat-Aqaba are analyzed. • Paleomagnetic records and cosmogonic burial ages constrain the sediments' age. • The Gulf is spreading northward with an evaluated subsidence rate of ∼2 mm/yr. [ABSTRACT FROM AUTHOR]

Although the general geomorphology is reasonably well understood, not much information is available on the incision rates of rivers and related tectonic uplift in the central parts of the Balkan Peninsula. Caves in the lower part of Crna Reka drainage (N. Macedonia) provide the possibility to reconstruct the Neogene-Quaternary evolution of this area, as previous research has identified two major cave development phases: one related to Pliocene-Early Pleistocene basin infilling and establishment of lacustrine environments, and a subsequent cave development phase related to valley incision due to draining of the lacustrine systems and tectonic uplift. Here, we present new geochronological data obtained by U-Th dating on speleothems and cosmogenic nuclide burial age determination of clastic cave sediments, that provide time constraints on the Pleistocene karst and valley evolution, and an insight into the related tectonic uplift. The obtained cosmogenic nuclide burial age (2.1 ± 0.5 Ma) of the clastic cave sediments from Temna Peštera – Dragožel, further supports previous results on placing the onset of the draining of the Pliocene lakes in Macedonia in the Early Pleistocene. The similar timing obtained for the downstream and upstream parts of Crna Reka drainage suggests that the draining was more likely initiated by regional uplift, rather than headward erosion related to subsidence in the Aegean Sea. The Middle to Late Pleistocene age of the dated speleothems agrees well with the existing conceptual model for karst and landscape evolution in the area. The cumulative valley incision rates based on these radiometric data show an increase towards the present, with values of <0.1 m/ka in Early Pleistocene, increasing to ∼0.2–0.5 m/ka in Middle Pleistocene, and up to 1 m/ka in Late Pleistocene. They are lower than the measured uplift rates in the area (1.1–1.2 m/ka), and mostly overlap with the range of GPS-based vertical deformation rates in the Hellenides. Higher Middle to Late Pleistocene uplift rate is inferred in the downstream part of Crna Reka, an area in the Vardar zone bounded by seismogenic faults, than in the upstream part, at the easternmost edge of the Pelagonian massif. • 26Al/10Be burial dating shows Early Pleistocene valley incision and cave development. • Further evidence on Early Pleistocene draining of the Central Macedonian Lake • Middle to Late Pleistocene age of speleothems confirmed by U-Th dating • Valley incision rates increase from Early (<0.1 m/ka) to Late Pleistocene (≤1 m/ka). • Higher uplift rates are inferred in the downstream parts of Crna Reka drainage. [ABSTRACT FROM AUTHOR]

• The Vosges Massif: a formerly half-glaciated massif. • 10Be- and 26Al-based catchment-wide denudation rates at the massif scale. • 40% of the studied catchments (9/22) are in cosmogenic disequilibrium. • Glacial deposits and former glacial cover correlates with 26Al/10Be ratios. • Sediments sampled in non-steady catchments might have survived several glacial cycles. Although catchment-wide denudation rates inferred from in situ cosmogenic nuclide concentrations measured in stream sediments has represented a ground-breaking progress in geomorphology over the last three decades, most of these studies rely on 10Be concentrations only. It seems that this current and routine one-nuclide approach to infer catchment-wide denudation rates has somehow overshadowed two key assumptions that are cosmogenic steady-state and short sediment transit time at the catchment scale. Although a paired-nuclide approach allow testing these assumptions, it is rarely performed on stream sediments and this can become highly problematic in slow-eroding, formerly glaciated contexts. In this study, we thus measure both 10Be and 26Al in stream sediments pertaining to twenty-one rivers draining an entire low mountain range: the Vosges Massif (NE France). The latter exhibits a sharp gradient between its southern and northern part in terms of lithology, morphometry and climate. Moreover, if its northern part remained void of glacial cover during Quaternary cold stages, its southern part was significantly and repeatedly glaciated. We aim to assess the factors that control the denudation of the Vosges Mountains and to quantitatively explore the impact of both repeated glacial cover and storage of glacially derived sediments on 26Al/10Be ratios, hence cosmogenic (un-)steadiness in modern river samples. Our results first show that elevation, slope, channel steepness and precipitation are primarily organised along a N-S increasing trend. 10Be- and 26Al-derived catchment-wide denudation rates accordingly range from 34 ± 1 to 66 ± 2, and 41 ± 3 to 73 ± 7 mm/ka, respectively, in thirteen investigated catchments that are in cosmogenic equilibrium. Lithological contrasts may control the pattern of denudation with a higher erodibility of the sandstone-dominated catchment to the north compared to the crystalline-dominated catchments to the south. Our results also show that catchments in strong cosmogenic disequilibrium (26Al/10Be ratios from 1.4 to 5.2) spatially cluster in the SW part of the Vosges Mountains that was the most intensively glaciated during Quaternary cold stages. If this precludes any conclusion about controlling factors at the whole massif scale, this study is the first to quantify the impact of past glaciations on cosmogenic (un-)steadiness measured in stream sediments. A statistically significant relationship between the degree of depletion of the 26Al/10Be ratios and the spatial pattern of glaciation is found: the larger the former glacial cover in each catchment, the lower the 26Al/10Be ratio. Equally important is the significant correlation reported between the degree of depletion of the 26Al/10Be ratios and the proportion of glacial and fluvio-glacial deposits within each catchment. These two relationships underline the link between cosmogenic unsteadiness in the stream cosmogenic signal and long-lasting and repetitive ice shielding, and complex sediment routing systems in glacial environments, respectively. We thus argue to systematically measure 26Al in complement to 10Be and to test the steady-state assumption when it comes to infer catchment-wide denudation rates from modern stream sediments, especially in slow eroding, formerly glaciated landscapes. [ABSTRACT FROM AUTHOR]

We present the results of a new dating study carried out at Lunery-la Terre-des-Sablons (LTS) and Brinay-la Noira (BN), two key Lower Palaeolithic sites located in deposits associated to the Cher River (Middle Loire Catchment, France). These sites preserve abundant Mode 1 and Mode 2 lithic industries, and are considered as among the oldest evidence of hominin presence in Western Europe north of the 45°N latitude. Following a multi-technique approach combining electron spin resonance (ESR), single-grain thermally-transferred optically stimulated luminescence (TT-OSL) dating of quartz grains and palaeomagnetism, we obtained new chronological constraints for the sedimentary sequence, and the associated lithic assemblages, at the two sites. The new independent dating results derived from each method are consistent and in overall agreement with existing ESR and terrestrial cosmogenic nuclide (TCN) burial age estimates, except for the Lowermost Unit 3 at LTS. By integrating all of the previous and new dating results, we derive combined age estimates of 772-735 ka and 665 ± 29 ka for the fluvial sands at LTS (Unit 1) and BN, respectively. These two distinct aggradation phases may tentatively be correlated to interglacial/glacial transitions associated with Marine Isotope Stage (MIS) 19-18 for the former and MIS 17-16 for the latter. At BN, an age range of 638–676 ka may be proposed for the hominin occupation after combining numerical age results and geological evidence. This result is consistent with the initial chronology proposed by Moncel et al. (2013) [Moncel, M.H., Despriée, J., Voinchet, P., Tissoux, H., Moreno, D., Bahain, J. J., Courcimault, G., Falgueres, C. (2013). Early evidence of Acheulean settlement in north-western Europe – la Noira site, a 700 000 year-old occupation in the Centre of France. Plos One, 8(11): 1–22] and confirms that BN is among the oldest Acheulean occurrences in Western Europe. At LTS, the mean age of 710 ± 50 ka obtained for the sandy layer in Unit 3 provides a minimum age constraint for the archaeological level located below. The major sedimentary disconformity observed between the fluvial deposits and the underlying pebble layers hosting the lithic artefacts suggests that the true age of the artefacts might be significantly older, probably Early Pleistocene given their similarities with other Mode 1 assemblages identified in Western Europe. However, further refinement of the Mode 1 chronological inference at LTS remains difficult at this stage. Finally, these new dating results show the importance of using the Multiple Centre approach for ESR dating of quartz grains, and confirm the value of combining different dating methods in order to build more robust chronologies for Lower Palaeolithic sites in Europe. From a methodological point of view, the dating results presented here are especially encouraging for the reliability of the ESR method applied to optically bleached quartz grains. This is one of the very first studies demonstrating that quartz samples independently dated by two different laboratories may produce generally reproducible ESR age results. • New dating results for the Lower Palaeolithic sites of Lunery-la Terre-des-Sablons (LTS) and Brinay-la Noira (BN), France. • A multi-technique approach was employed, combining multiple centre ESR dating, single-grain TT-OSL dating and palaeomagnetism. • At BN, an age range of 638–676 ka may be proposed for the hominin occupation. • At LTS, the mean age result of 710 ± 50 ka oprovides a minimum age constraint for the archaeological level in Unit 3. [ABSTRACT FROM AUTHOR]

How post-burial terrestrial in situ cosmogenic nuclides (TCN) production is build-up in slow burial condition remains uncertain. In this study, we dated high fluvial terrace sediments that overlain by loess with a slow deposition rate that is based on the assumption of steady accumulation rate via 26Al/10Be burial dating method. For sample in deep and rapid buried condition prior to slow overlying, post-burial production shows low component (4–6%) in measured concentration. However, post-burial production occupied 39–79% of measured 26Al and 10Be concentrations, which suggests approximately 0.2–0.3 Ma underestimation in simple burial dating mode if post-burial production is neglected. Corrected by post-burial production, we yielded burial ages of two top terraces (ca. 1.7–2.5 Ma and 1.5 Ma, respectively) below the Tangxian planation surface along the Jinshan Gorge of the Yellow River, implying that the Jinshan Gorge initially incised at ca. 1.7–2.5 Ma, corresponding well to regional tectonic activities, such as extension in the Fenwei Graben, accelerative uplift of the Tangxian planation surface, vigorous dissection of North China, and significant tectonic deformation in northeastern Tibetan Plateau. The slow burial mode is probably a potential method for plateau paleo-elevation estimation taking advantage of height sensitivity of TCN production rate if overlying loess magnetostratigraphic age is known. [ABSTRACT FROM AUTHOR]

Concentrations of cosmogenic nuclides in rocks at the Earth's surface are routinely measured by AMS (accelerator mass spectrometry) to obtain exposure ages. One particular application of this technique has been to derive ages for the formation of marine terraces, thus allowing constraints to be placed on rates of tectonic uplift. However, multiple rock samples from the same terrace surface have typically shown an amount of scatter in cosmogenic nuclide concentrations in excess of analytical uncertainties, potentially undermining the confidence in the resulting uplift rates. In addition, earlier works have considered the application of bedrock samples for exposure age dating marine terraces, but little attention has been directed towards the validity of sampling clasts exposed on terrace surfaces. Here, we use 10Be and 26Al measurements from a flight of marine terraces in northern Chile to compare the results from pebbles with those from bedrock samples and to investigate assumptions that sample pre-exposure and burial are negligible. We examine the influence that processes of surface deflation and pebble erosion will have on cosmogenic nuclide concentrations using a Monte Carlo model, the results of which are compared to our 10Be measurements. We find good agreement of 10Be concentrations between bedrock and pebble samples. At the sampled location, sample burial is rare and 10Be inheritance in pebble samples is low relative to the age of the terraces. Our modelling suggests that in arid environments, such as northern Chile, pebble erosion will be a secondary effect compared to surface deflation and that multiple periods of deflation will result in multimodal distributions of 10Be concentrations. More broadly, our findings show that measuring multiple surface clasts from a single marine terrace reveals the geomorphological processes influencing exposure ages, and may also be used to help identify the operation of past surface processes such as episodic deflation. [ABSTRACT FROM AUTHOR]

Cosmogenic nuclides contained in the annual layers of natural materials record temporal variations in the galactic cosmic ray flux. 14C in tree rings and 10Be in ice cores from polar regions are often used to retrieve accurate histories of galactic cosmic rays. However, the variation in 14C produced in the atmosphere is strongly attenuated in the carbon cycle and the amplitude of decadal scale variations in tree rings is approximately 0.2‰. In the case of 10Be in ice cores, the variation remains at a relatively large amplitude; however, the records are accompanied by dating uncertainties. Another material that contains 10Be is sediment in continental areas. Terrestrial carbonate deposits sometimes form clear annual layers; however, detailed analyses on such deposits have not yet been widely conducted. Therefore, we evaluate the possibility of retrieving information concerning the galactic cosmic ray flux from the terrestrial carbonate deposits. In this paper, we report our preliminary results obtained from the measurements of 10Be in travertine and tufa samples from South China. We find that the 10Be flux obtained from the travertines is comparable to the level produced by galactic cosmic rays and that travertines might have potential as a tool for investigating past cosmic-ray variations with annual resolution. [ABSTRACT FROM AUTHOR]

The early Pleistocene travertines from Kocabaş in the Denizli Basin (SW Turkey), from which the only known Homo erectus from Anatolia derives, are covered by a succession of lake deposits. So far, the taphonomic history of the site has precluded a detailed palaeoecological analysis. This paper details the sedimentary succession and palaeoenvironmental conditions by analysing the micro- and macropalaeontological species compositions. These data provide direct evidence of the opportunities and limiting factors of the environment inhabited by hominins during the early Pleistocene. Four distinctive lithostratigraphic units are recognized in the Quaternary succession, consisting of: Lower Travertine, Lower Conglomerates, Upper Travertine, and Upper Conglomerates. These units correspond to an alternation of lacustrine limestone, fluvial-lacustrine siliciclastic deposits and subaerially precipitated travertine accumulations. The age of the succession is constrained by cosmogenic nuclide concentration, palaeomagnetic measurements and large mammal biostratigraphy which suggest deposition occurred between ∼1.6 and 1.2 Ma. The travertine succession contains a moderately diverse macromammal fauna, including Homo erectus , decapod crustaceans and leaf imprints. The herbivore association likely dwelled in a mixed landscape during temperate and humid climatic conditions, supported by negative δ18O values from analysed gastropod and bivalve shells. The presence of an anomalohaline lake is indicated by an abundant and well-preserved ostracod community, consisting of alkaline tolerant taxa and freshwater genera further supported by the presence of cardiid bivalves. [ABSTRACT FROM AUTHOR]

Cosmogenic nuclide surface exposure dating and erosion rate measurements in basaltic landscapes rely primarily on measurement of 3He in olivine or pyroxene. However, geochemical investigations using 3He have been impossible in the substantial fraction of basalts that lack separable olivine or pyroxene crystals, or where such crystals were present, but have been chemically weathered. Fine-textured basalts often contain small grains of ilmenite, a weathering-resistant mineral that is a target for cosmogenic 3He production with good He retention and straightforward mineral separation, but with a poorly constrained production rate. Here we empirically calibrate the cosmogenic 3He production rate in ilmenite by measuring 3He concentrations in basalts with fine-grained (∼20 μm cross-section) ilmenite and co-existing pyroxene or olivine from the Columbia River and Snake River Plain basalt provinces in the western United States. The concentration ratio of ilmenite to pyroxene and olivine is 0.78 ± 0.02, yielding an apparent cosmogenic 3He production rate of 93.6 ± 7.7 atom g−1 yr−1 that is 20–30% greater than expected from prior theoretical and empirical estimates for compositionally similar minerals. The production rate discrepancy arises from the high energy with which cosmic ray spallation reactions emit tritium and 3He and the associated long stopping distances that cause them to redistribute within a rock. Fine-grained phases with low cosmogenic 3He production rates, like ilmenite, will have anomalously high production rates owing to net implantation of 3He from the surrounding, higher 3He production rate, matrix. Semi-quantitative modeling indicates implantation of spallation 3He increases with decreasing ilmenite grain size, leading to production rates that exceed those in a large grain by ∼10% when grain radii are <150 μm. The modeling predicts that for the ilmenite grain size in our samples, implantation causes production rates to be ∼20% greater than expected for a large grain, and within uncertainty resolves the discrepancy between our calibrated production rate, theory, and rates from previous work. The redistribution effect is maximized when the host rock and crystals differ substantially in mean atomic number, as they do between whole-rock basalt and ilmenite. [ABSTRACT FROM AUTHOR]

We present a new in-situ cosmogenic 14C extraction system developed at ETH Zürich. This system quantitatively extracts 14C produced in quartz by cosmic rays using a high temperature extraction procedure. A key improvement of the new extraction system is the implementation of largely automated sequences, CO 2 transport in a He flow and the addition of a "dead" CO 2 carrier gas, which ensure highly reproducible operation while limiting the required operator attendance. Intercomparison quartz samples were routinely measured over a year of operation and yield 14C concentrations of 7.27 (±0.03) · 105 at/g quartz for CRONUS-A (n = 7) and 1.24 (±0.17) · 104 at/g quartz for CRONUS-N (n = 4). The excellent performance of the new system is highlighted by low procedural blanks of ca. 3 · 104 14C atoms and coefficients of variation for the CRONUS-A and CRONUS-N analyses of only 0.4% and 14% respectively. [ABSTRACT FROM AUTHOR]

Cosmogenic in situ 14C in quartz is rapidly becoming a widely used geochronological tool for studying earth surface processes over the last 30,000 years. The Lamont-Doherty Earth Observatory houses one of the longest continuously-operating cosmogenic in situ 14C laboratories; in this contribution, we provide an update on the status of the laboratory following Goehring et al. (2014). From 2010 to the present, our long-term average blank value is 119,000 ± 37,000 14C atoms, with no statistically significant trend over the last nine years. While our average measured 14C concentration of the CRONUS-A inter-laboratory comparison standard is in line with data published from other laboratories, we note a step increase between 2013 and 2015 that is still under investigation. Additionally, we report our first procedural blanks and CRONUS-A values analyzed on the gas source of the AixMICADAS at CEREGE, France. Many of the >75 samples analyzed at Lamont for in situ 14C from the Arctic, Antarctic, New Zealand, and the Alps have been paired with 10Be analyses contributing to the increasing density of burial dating data covering the last 20,000 years. Currently we are working on increasing sample throughput, streamlining the 14C extraction procedure, and considerably decreasing blank levels. [ABSTRACT FROM AUTHOR]

• Too short aging of hydroxides can be reason for low chemical yield of oxides. • 2-times rinsing of hydroxides recommended for Be(OH) 2 and Al(OH) 3. • Rinsing with H 2 O (pH5) instead of pH8-9 recommended for Al(OH) 3. • Rinsing of Fe(OH) 3 with coprecipitated U6+ and Er3+ yield to 2.6–3.5% losses only. • High potential for ion exchange as pre-enrichment tool for Cl for large ice samples. A major research focus of the DREsden Accelerator Mass Spectrometry (DREAMS) facility is sample preparation: in-house and at cooperating laboratories. Besides routine applications, developments are mainly driven by the users' demands such as "new" radionuclides (e.g. short-lived 7Be), radionuclides from new matrices or in larger sample amounts and at lower concentrations. Within the chemical preparation of BeO for 7,10Be, Al 2 O 3 for 26Al, AgCl for 36Cl, and Fe 2 O 3 for 60Fe and actinide AMS targets, we investigated and improved mostly particular steps: For oxide preparation aging for several hours and two-times rinsing of hydroxides is recommended, especially for Be(OH) 2 and Al(OH) 3 , to prevent losses in the final preparation steps. Rinsing of freshly precipitated hydroxides can yield to losses as high as 31%. For Al(OH) 3 rinsing with H 2 O (pH5) instead of pH8-9 is recommended for further reducing redissolving. For 60Fe and coprecipitated actinides (the latter tested by U6+ and Er3+), rinsing of overnight-aged Fe(OH) 3 , yield to 2.6–3.5% losses. The depletion of the isobar 7Li for (7)BeO is easily gained by hydroxide precipitation and rinsing. The quality of BeO and Al 2 O 3 AMS targets can be monitored and improved (e.g. by using larger ion exchanger columns) by using the so-called "quality factor", which is the current of the stable nuclide (9Be or 27Al), normalised to the current of the standard of the same batch. Finally, there is a high potential for ion exchange as a pre-enrichment tool for Cl for large ice samples containing low natCl concentrations and low absolute amounts of natCl. [ABSTRACT FROM AUTHOR]

• Pre-Acheulean industry dating at Dungo IV site (Baia Farta, Benguela, Angola). • Burial of the hominin occupation surface since at least 614 ka. • Apparent maximum uplift rate at the site of 170 m.Ma −1. Along the Angolan coast, the Early Paleolithic sites of Dungo IV and V (Baia Farta, Benguela) have delivered a rich pre-Acheulean lithic industry testifying the antiquity of the hominin settlement in western Africa despite the current absence of any hominin fossil in the area. In Dungo IV, the Paleolithic level is located on a conglomeratic paleo-beach (104 m a.s.l.) buried under an at least 3 m thick sandy layer. In Dungo V, two unearthed large whale fossils are associated with numerous lithic tools intimately mixed with the whale bones. This is the oldest evidence of stranded marine mammal scavenging by hominins in this part of Africa. The lack of volcanism and fossils makes chronological constrain difficult. Considering its configuration, the Dungo IV site may be relevant for a dating based on both the 10Be and 26Al cosmogenic nuclides. For this purpose, a depth profile all along the sandy layer overlying the archeological layer has been sampled. Statistical treatments performed on the 26Al/10Be ratios obtained for the depth profile demonstrate that they all belong to the same population. If we consider that the samples have always been at or close to their sampling depth, the regression modeling allows computing that the surface sedimentary layer has been emplaced at least 614 ka ago and less than 662 ka ago. On the other hand, if we consider that the surface deposit has been truncated, burial durations ranging from 585 ka to 786 ka and truncations lower than 4 m result from the modeling of the evolution of the 10Be and 26Al concentrations as a function of depth. The analyses of four pre-Acheulean artefacts lead to a minimum burial duration of 730 ka and a maximum burial duration of 2.11 Ma. The low pre-burial denudation rates modeled from the data acquired for the stone tools as well as for the overlying layer (1–16 m.Ma −1) imply large inherited 26Al and 10Be concentrations. The post-depositional maximum denudation rate of 71 m.Ma −1 associated with both the lithic artefacts and the surface sedimentary layer (considering that the samples have always been at or close to their sampling depth) as well as the deduced maximum uplift rate of ∼170 m.Ma −1 are in agreement with the known tectonic evolution and the climatic variability of this area. This study confirms the antiquity of the hominin presence in western Africa more than 2000 km away from the closest old hominin fossil sites. [ABSTRACT FROM AUTHOR]

• Liquid reference material for quality control of cosmogenic 10Be and 26Al analyses. • Ratios similar to late glacial samples (10Be/9Be ∼ 1.4 × 10−13; 26Al/27Al ∼ 4.4 × 10−13). • Available free of charge to the community. • Initial analyses match suggested values for source material (CRONUS-A) Analysis of the in situ produced cosmogenic nuclides 10Be and 26Al has been used for several decades to study Earth surface processes; yet, no reference material has been widely adopted and used by the community to ensure the quality and comparability of sample preparation and isotopic analyses. Such a reference material could facilitate inter-laboratory comparison and serve as a benchmark for quantifying the accuracy, precision, and long-term reproducibility of terrestrial cosmogenic nuclide analyses. Here, we describe a liquid reference material, UVM-A, which is freely available to the community. We created four liters of solution by dissolving CRONUS-A granular reference material [1] , and spiking the solution with stable 9Be and 27Al, yielding a solution containing 236.7 ± 0.6 μg g−1 Be and 932.6 ± 1.6 μg g−1 Al (average, 1SD). Initial analyses of UVM-A indicate that the nuclide ratios of the reference material (10Be/9Be 1.43 ± 0.02 × 10−13; 26Al/27Al 4.44 ± 0.05 × 10−13; average, standard error) are similar to those of late-glacial exposure samples, are tightly clustered, and match the nuclide concentrations expected from the CRONUS-A quartz used to prepare the reference material. Use of this reference material will help to quantify uncertainty in cosmogenic exposure ages, burial ages, and erosion rates resulting from sample preparation and isotopic analysis. [ABSTRACT FROM AUTHOR]

There is growing interest in geochronological applications of terrestrial in situ -produced cosmogenic nuclides, with the most commonly measured being 10Be and 26Al in quartz. To extract and then separate these radionuclides from quartz and prepare them in the oxide form suitable for accelerator mass spectrometry (AMS) requires extensive and careful laboratory processing. Here we discuss the suitability of a crushed, sieved and etched, sub-aerially exposed vein quartz specimen (CoQtz-N) to act as a reference material for chemical laboratory preparation and AMS measurements. Splits of CoQtz-N were distributed to eleven target preparation laboratories. The CoQtz-N 10Be targets were then measured at seven different AMS facilities and five of the preparation laboratories had their 26Al targets measured at four different AMS facilities. We show that CoQtz-N splits are sufficiently homogeneous with regard to nuclide concentrations, that it has been cleaned of any atmospheric derived (i.e. meteoric) 10Be and that it has low concentrations of the major elements that can interfere with Be and Al extraction chemistry and AMS measurements. We derive preliminary concentrations for 10Be and 26Al in CoQtz-N as 2.53 ± 0.09 × 106 at/g and 15.6 ± 1.6 × 106 at/g, respectively, at the 95% confidence limit. [ABSTRACT FROM AUTHOR]

The growing number of studies based on data provided by the accelerator mass spectrometry (AMS) technique from increasingly diverse matrices implies that developing very effective and reproducible sample processing techniques is crucial to meet the demand generated. After being dissolved, the isolation of the cosmogenic nuclide to be measured and its chemical purification imply complex processes throughout successive stages The presented automatic system was designed to perform the final steps of the 10Be and 26Al chemical extraction protocol from natural matrices (sediments, pure mineral phases,...), previously purified, decontaminated and dissolved in the case of in situ-produced cosmogenic nuclides, or leached or dissolved in the case of meteoric cosmogenic nuclides. Driven by Labview software, the developed automatic system, in addition to freeing the operator from tedious tasks, allows reproducibly processing simultaneously up to eight samples of different volumes in roughly 40 min. This article presents the design of the automated extraction bench and its performance based on the recovery efficiency of the stable element and the reproducibility of the measurements of the cosmogenic nuclide concentrations by AMS. [ABSTRACT FROM AUTHOR]

Quantifying denudation rates under different climatic and tectonic settings is fundamental to understanding landscape evolution. Carbonate rocks may respond differently to climatic and tectonic forcings than other rock types because of their tendency to dissolve congruently. Yet, there is little information on the long-term denudation rate of carbonates and their controlling factors in different settings. Here, we present the first long-term denudation rates for carbonates in the south of the Central Anatolian Plateau. We quantified the outcrop denudation rates using in-situ cosmogenic 36Cl measured in 13 rock samples to evaluate spatial variations and potential controls on the style and rate of denudation. 36Cl-derived denudation rates range from 1.92 ± 0.31 to 45.77 ± 3.91 mm/ka. On the plateau, denudation rates are strongly correlated with precipitation and are lower than the theoretical maximum dissolution rates predicted assuming zero evaporation, implying that climate exerts the major control on carbonate denudation. These results indicate that chemical weathering is the prevalent denudation style. The denudation pattern shows spatial variability with a decreasing trend from SW to NE consistent with climate zones. High-to-moderate denudation rates occur in the continental climate, while the lowest denudation rates occur in the arid plateau interior. In the Mediterranean coastal region, measured denudation rates are higher than the predicted maximum dissolution rates, reflecting the mechanical removal of overlying rock or soil. The low denudation rates in the plateau interior indicate a slowly evolving landscape with an arid climate. The physical properties of rocks showed the weakest control on carbonate denudation. In the Central Taurides, significant infiltration of surface runoff resulted in strong subsurface karstification at the expense of surface drainage. This process caused disequilibrium between uplift and denudation and resulted in the preservation of high-elevation topography. Therefore, in the actively uplifting plateau margin, the influence of tectonics on carbonate denudation has been interfered with the impact of precipitation and subsurface karstification. • 36Cl-derived denudation rate of carbonate rocks ranges from 1.92 to 45.77 mm/ka. • Precipitation exerts a major control on denudation of carbonate rocks. • Chemical weathering is the dominant style of denudation on the plateau. • Denudation pattern shows spatial variability with a decreasing trend from SW to NE. • The efficient drainage of runoff by karstification delayed the response to uplift. [ABSTRACT FROM AUTHOR]

The most recent deglaciation of the North American Ice Sheet Complex (NAISC: comprising the Innuitian, Cordilleran, and Laurentide ice sheets) offers a broad perspective from which to analyze the timing and rate of ice retreat, deglacial sea-level rise, and abrupt climate change events. Previous efforts to portray the retreat of the NAISC have been focused largely on minimum-limiting radiocarbon ages and ice margin location(s) tied to deglacial landforms that were not, for the most part, chronologically constrained. Here, we present the first version of North American Deglaciation Isochrones (NADI-1) spanning 25 to 1 ka in calendar years before present. Key new features of this work are (i) the incorporation of cosmogenic nuclide data, which offer a direct constraint on the timing of ice recession; (ii) presentation of all data and time-steps in calendar years; (iii) optimal, minimum, and maximum ice extents for each time-step that are designed to capture uncertainties in the ice margin position, and; (iv) extensive documentation and justification for the placement of each ice margin. Our data compilation includes 2229 measurements of 10Be, 459 measurements of 26Al and 35 measurements of 36Cl from a variety of settings, including boulders, bedrock surfaces, cobbles, pebbles, and sediments. We also updated a previous radiocarbon dataset (n = 4947), assembled luminescence ages (n = 397) and gathered uranium-series data (n = 2). After scrutiny of the geochronological dataset, we consider >90% of data to be reliable or likely reliable. Key findings include (i) a highly asynchronous maximum glacial extent in North America, occurring as early as 27 ka to as late as 17 ka, within and between ice sheets. In most marine realms, extension of the ice margin to the continental shelf break at 25 ka is somewhat speculative because it is based on undated and spatially scattered ice stream and geomorphic evidence; (ii) detachment of the Laurentide and Cordilleran ice sheets took place gradually via southerly and northerly 'unzipping' of the ice masses, starting at 17.5 ka and ending around 14 ka; (iii) the final deglaciation of Hudson Bay began at 8.5 ka, with the collapse completed by 8 ka. The maximum extent of ice during the last glaciation occurred at 22 ka and covered 15,470,000 km2. All North American ice sheets merged at 22 ka for the first time in the Quaternary. The highly asynchronous Last Glacial Maximum in North America means that our isochrones (starting at 25 ka) capture ice advance across some areas, which is based on limited evidence and is therefore somewhat speculative. In the Supplementary Data, the complete NADI-1 chronology is available in PDF, GIF and shapefile format, together with additional visualizations and spreadsheets of geochronological data. The NADI-1 shapefiles are also available at https://doi.org/10.5281/zenodo.8161764. • Uncertainties captured in optimal, minimum, and maximum ice extents. • Detailed documentation for the placement of each ice margin. • NADI-1 ice margins available in.shp,.pdf and.gif format for 49 timesteps. • Supplementary Data: additional visualizations, geochronological data. [ABSTRACT FROM AUTHOR]

The aim of this work is to build a new chronology of the Late Pleistocene glacial fluctuations in the Cantal Mountains and on the Cézallier Plateau (western Massif Central, France). The study of glacial landform-sediment assemblages is supported by the production of new exposure ages (n = 48) from (i) forty-three erratic boulders (36Cl and 10Be) spread over twelve glacial landforms, (ii) two ages from polished bedrocks (10Be) and (iii) three ages from depth profiles (10Be and 26Al) in tills. The results indicate that the majority of glacial deposits are attributed to Marine Isotopic Stage 2 (29 to 11 ka). From this dataset, four glacial stadials are discriminated: the Early-Local Last Glacial Maximum at 29–24 ka, (ii) Late-Last Glacial Maximum at 24–20 ka, (iii) a glacial still stand at approximately 17 ka, during a general deglaciation phase between 20 and 16 ka and finally (iv) a cirque stadial localized only in the Cantal Mountains at <16 ka. This new chronology strengthens the chronostratigraphy of the western Massif Central and highlights the sensitivity of the area to atmospheric circulation changes. • Revisions of glacial landform-sediment assemblages define four distinct glacial events. • Glacial fluctuations are dated to the MIS 2 with surface exposure ages using 10Be, 26Al and 36Cl (n = 48). • Two major glacier advances occurred during the Last Glacial Maximum, at 29–24 and 24–20 ka. • The paleoglacier is limited to the Cantal cirques from ~16 ka. • Paleoglacier from the western Massif Central are sensitive to north Atlantic paleoclimatic changes. [ABSTRACT FROM AUTHOR]

The Tashkurgan normal fault in the Eastern Pamir is located at the strain transition zone between the dextral strike-slip faulting of the Karakoram fault in the south and the east-west extension of the Kongur Shan extensional system (KES) in the north. Thus, its tectonic evolution and relationship with the KES and the Karakoram fault carry important implications for the strain partition and deformation history of the Pamirs. However, the Tashkurgan fault lacks systematic documentation of its evolution and its relationship to other regional tectonic structures. In order to constrain the tectonic activity of the Tashkurgan fault, we analyze the landscape and 10Be-derived erosion rates in the footwall of the Tashkurgan fault. Our results reveal that both the values of the geomorphological indices and erosion rates increase from the northern segment of the fault towards the central segment and then decrease again southwards but with a further increase in the southernmost segment. We interpret that this pattern is closely related to the fault-related uplift of the Tashkurgan fault except that the southernmost segment is mainly affected by fractured rocks. These observations together with previous studies suggest that the Tashkurgan fault is the southern segment of the KES and extension along the KES has been initiated from the north and transferred to the Tashkurgan fault through the Tagharma fault. Therefore, we infer that the normal faulting of the Tashkurgan fault, and probably the whole KES, may lack a kinematic connection to the dextral slip system in the south. • Fault connections in the Eastern Pamir are investigated. • Landscape and erosion are studied in the footwall of the Tashkurgan normal fault • Erosion rates and landscape features mirror fault-related uplift • The Tashkurgan fault is the southern part of the Kongur Shan extensional system • Extension along the Kongur Shan extensional system is initiated from the north [ABSTRACT FROM AUTHOR]

The shergottites are the most abundant and diverse group of Martian meteorites and provide unique insights into the mafic volcanic and igneous history of Mars. Their ages, however, remain a source of debate. Different radioisotopic chronometers, including 40Ar/39Ar, have yielded discordant ages, leading to conflicting interpretations on whether the shergottites originate from young (mostly <700 Ma) or ancient (>4,000 Ma) Martian volcanoes. To address this issue, we have undertaken an 40Ar/39Ar investigation of seven shergottite meteorites utilizing an innovative approach to correcting data for cosmogenic isotope production and resolution of initial trapped components which, crucially, do not require assumptions concerning the sample's geologic context. Our data yield statistically robust 40Ar/39Ar isochron ages ranging from 161 ± 9 Ma to 540 ± 63 Ma (2 σ), synchronous with the U-Pb, Rb-Sr, and Sm-Nd ages for the respective meteorites. These data indicate that, despite experiencing shock metamorphism, the shergottites were sourced from the youngest volcanoes on Mars. • Literature shergottite 40Ar/39Ar ages typically older than other chronometers. • Led to suggestions of impact resetting or 'parentless' argon sources. • In contrast, our 40Ar/39Ar analyses yield ages concordant with other chronometers. • Accurate corrections are required for terrestrial and cosmogenic argon. • Shergottite meteorites are from the youngest volcanoes on Mars. [ABSTRACT FROM AUTHOR]

Erosion rates are widely used to assess tectonic uplift and sediment export from mountain ranges. However, the scarcity of erosion rate measurements often hinders detailed tectonic interpretations. Here, we present 25 new cosmogenic nuclide-derived erosion rates from the Northern Andes of Colombia to study spatio-temporal patterns of uplift along the Central and Eastern Cordillera. Specifically, we combine new and published erosion rate data with precipitation-corrected normalized channel steepness measurements to construct high-resolution erosion rate maps. We find that erosion rates in the southern Central Cordillera are relatively uniform and average ∼0.3 mm/a. In the northern Central Cordillera rapidly eroding canyons dissect slowly eroding, low-relief surfaces uplifting since 8.3 − 2.6 + 3.7 Ma, based on a block uplift model. We interpret that persistent steep slab subduction has led to an erosional steady-state in the southern Central Cordillera, whereas in the northern Central Cordillera, Late Miocene slab flattening caused an acceleration in uplift, to which the landscape has not yet equilibrated. The Eastern Cordillera also displays pronounced erosional disequilibrium, with a slowly eroding central plateau rimmed by faster eroding western and eastern flanks. Our maps suggest Late Miocene topographic growth of the Eastern Cordillera, with deformation focused along the eastern flank, which is also supported by balanced cross-sections and thermochronologic data. Spatial gradients in predicted erosion rates along the eastern flank of the Eastern Cordillera suggest transient basin-ward migration of thrusts. Finally, sediment fluxes based on our erosion maps, suggest that the Eastern Cordillera exports nearly four times more sediment than the Central Cordillera. Our analysis shows that accounting for spatial variations in erosion parameters and climate reveals important variations in tectonic forcing that would otherwise be obscured in traditional river profile analyses. Moreover, given relationships between tectonic and topographic evolution, we hypothesize that spatio-temporal variations in slab dip are the primary driver of the dynamic landscape evolution of the Northern Andes, with potentially superposed effects from inherited Mesozoic rift structures. • high-resolution erosion rate maps from topographic and cosmogenic nuclide data. • changes in subduction geometry drove topographic development in Northern Andes. • Northern Andes in erosional disequilibrium, except southern Cordillera Central. • Quantification of surface uplift from erosion rate maps. • highest sediment export to Llanos basin with potential influence on biodiversity. [ABSTRACT FROM AUTHOR]

The Sun is the main energy source to Earth, and understanding its variability is of direct relevance to climate studies. Measurements of total solar irradiance (TSI) exist since 1978, but this is too short compared to climate-relevant time scales. Coming from a number of different instruments, these measurements require a cross-calibration, which is not straightforward, and thus several composite records have been created. All of them suggest a marginally decreasing secular trend in solar minima levels since 1996. Most composites actually feature a weak decrease over the entire period of observations, which is also seen in observations of the solar surface magnetic field and is further supported by Ca ii K data. Some inconsistencies, however, remain and overall the magnitude and even the presence of the secular change over the satellite era remain uncertain. Different models have been developed, which are used to understand the irradiance variability over the satellite period and to extend the records of solar irradiance back in time. Differing in their methodologies, all models require proxies of solar magnetic activity as input. The most widely used proxies are sunspot records and cosmogenic isotope data on centennial and millennial time scale, respectively. None of this, however, offers a sufficiently good, independent description of the long-term evolution of faculae and network responsible for solar brightening. This leads to significant uncertainties in the amplitude of the changes in solar irradiance on time scales longer than the solar cycle. Here we review recent efforts and advances aiming at improving long-term irradiance reconstructions and to reduce the existing uncertainty in the magnitude of the long-term variability. In particular, by employing state-of-the-art 3D magnetohydrodynamical simulations, an upper limit of 2 ± 0. 7 W m−2 was set on the possible increase of TSI since the end of the Maunder minimum as compared to the 2019 minimum level. Besides, significant progress has been made in collecting and processing historical solar observation in Ca ii K spectral line, which provide direct information on bright magnetic features on the Sun and can be used to improve the accuracy of past irradiance reconstructions, pending some remaining issues with the data. • Most TSI composites evidence a weak secular decrease, within measurement uncertainties. • Weak TSI decrease over the last decades is supported by magnetic field and Ca ii K data. • The upper limit on TSI increase between Maunder minimum and 2019 is 2 ± 0. 7 W m−2. • Historical solar Ca ii K data provide missing information on facular evolution in the past. • Ca ii K observations can help reducing the uncertainty in the long-term TSI change. [ABSTRACT FROM AUTHOR]