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Chum salmon ( Oncorhynchus keta) in the North Pacific Ocean are anadromous fish, and spend most of their life in the sea until spawning in natal streams. To identify the stock and habitat characteristics of chum salmon, the composition of chemical elements (Ca, Mn, Sr, Zn, and Ba) in otolith was examined using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Two main types of analytical work have been carried out; discrete spot analysis and line scan analysis of otolith sections. Salmon otoliths were obtained from the eastern (Canada and USA) and western (Japan and Korea) North Pacific during 1997-1999 spawning seasons. Spot analysis of otolith cores demonstrated significant differences in the element concentration among countries (p = 0.003). Line scanning from the core to the margin showed that Sr concentrations were elevated at the core of the otoliths, decreased during the freshwater stage, increased suddenly at a certain point, and oscillated periodically towards the margin matching with year-ring. The elevated Sr concentration at the core may reflect the maternal contribution to the egg, and the oscillations toward the margin may reflect salinity gradients between onshore/offshore or north/south migrations. The Zn profiles also oscillated and corresponded to the annual ring of the otolith. However, the profiles of Sr and Zn oscillated oppositely after salmon migrated to saline water and the Zn uptake declined toward the rim of the otolith while Sr uptake increased. [ABSTRACT FROM AUTHOR]

Trace elements and U-Th-Pb isotopes of hydrothermal allanite from the Beiminghe iron skarn deposit (eastern North China Craton) were simultaneously analyzed using laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) to demonstrate the suitability and robustness of the U-Th-Pb system in this phase as a geochronometer of ore-forming processes. Allanite grains from the Beiminghe deposit, typically exhibit optical and chemical zoning and are intergrown or texturally equilibrated with prograde and/or retrograde skarn assemblages mainly consisting of tremolite, diopside, magnetite, and garnet. In addition, they contain abundant aqueous two-phase or daughter mineral-bearing three-phase aqueous fluid inclusions, confirming their hydrothermal origin. Most grains have high La/Ce ratios (1.19-1.74) and thus are classified as allanite-(La). A notable feature of the hydrothermal allanite-(La) is the lack of common Pb, with values comparable with those of the zircon standards 91500 and GJ-1 used in this study. LA-ICPMS spot analyses reveal remarkable variation in Ca, REEs (rare earth elements), Fe, Al, and Mg within a single grain, consistent with the substitution of REE. [ABSTRACT FROM AUTHOR]

The effectiveness of pelvic fin ray microchemistry of muskellunge, Esox masquinongy Mitchill, to identify stocked individuals along with the potential to identify naturally reproduced fish were evaluated. Fish and water samples were obtained from one hatchery and seven lakes with natural differences in water Sr:Ca to determine whether location-specific environmental signatures were recorded in sectioned muskellunge pelvic fin rays, including fish of known environmental history. Water and fin ray Sr:Ca were strongly correlated. Six lakes in Illinois possessed Sr:Ca signatures that were distinct from the hatchery where muskellunge were raised, resulting in pronounced shifts in Sr:Ca across sectioned fin rays of stocked fish. Hatchery and lake-specific Sr:Ca signatures were stable across years. Sixteen of 19 individual fish known to have been stocked based on PIT tags implanted at stocking were correctly identified as hatchery-origin fish using fin ray core Sr:Ca. Results also indicated that the hatchery Sr:Ca signal can be retained for at least 7 years in fin rays of stocked fish. Fin ray microchemistry is a non-lethal approach for determining environmental history of muskellunge that could be used to assess movement patterns in lake and river systems and the degree to which muskellunge populations are supported by natural reproduction and stocking. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is the leading cause of dementia in the elderly, affecting over 27 million people worldwide. AD represents a complex neurological disorder which is best understood as the consequence of a number of interconnected genetic and lifestyle variables, which culminate in multiple changes to brain structure and function. These can be observed on a gross anatomical level in brain atrophy, microscopically in extracellular amyloid plaque and neurofibrillary tangle formation, and at a functional level as alterations of metabolic activity. At a molecular level, metal dyshomeostasis is frequently observed in AD due to anomalous binding of metals such as Iron (Fe), Copper (Cu), and Zinc (Zn), or impaired regulation of redox-active metals which can induce the formation of cytotoxic reactive oxygen species and neuronal damage. Metal chelators have been administered therapeutically in transgenic mice models for AD and in clinical human AD studies, with positive outcomes. As a result, neuroimaging of metals in a variety of intact brain cells and tissues is emerging as an important tool for increasing our understanding of the role of metal dysregulation in AD. Several imaging techniques have been used to study the cerebral metallo-architecture in biological specimens to obtain spatially resolved data on chemical elements present in a sample. Hyperspectral techniques, such as particle-induced X-ray emission (PIXE), energy dispersive X-ray spectroscopy (EDS), X-ray fluorescence microscopy (XFM), synchrotron X-ray fluorescence (SXRF), secondary ion mass spectrometry (SIMS), and laser ablation inductively coupled mass spectrometry (LA-ICPMS) can reveal relative intensities and even semi-quantitative concentrations of a large set of elements with differing spatial resolution and detection sensitivities. Other mass spectrometric and spectroscopy imaging techniques such as laser ablation electrospray ionization mass spectrometry (LA ESI-MS), MALDI imaging mass spectrometry (MALDI-IMS), and Fourier transform infrared spectroscopy (FTIR) can be used to correlate changes in elemental distribution with the underlying pathology in AD brain specimens. Taken together, these techniques provide new techniques to probe the pathobiology of AD and pave the way for identifying new therapeutic targets. The current review aims to discuss the advantages and challenges of using these emerging elemental and molecular imaging techniques, and highlight clinical achievements in AD research using bioimaging techniques. [ABSTRACT FROM AUTHOR]

Transgenerational marking is increasingly being used to study the early life history, biology and ecology of fishes. However, the timeframe over which the injected enriched stable isotopes remain in the mother and are passed onto her offspring is largely unknown. Similarly, we have relatively little knowledge of the effects of isotope labelling on the morphology of offspring. In this study, we injected adult female eastern rainbowfish (Melanotaenia splendida) with two doses (20 µg g-1 and 40 µg g-1) of enriched 137Ba or 87Sr stable isotopes to mark the otoliths of their larvae and examine the effects of isotope labelling on larvae morphology. Isotope ratios in larval otoliths were significantly different from controls in larvae hatched up to 174 days post-injection, indicating that enriched isotopes can mark the larvae of this daily spawning species up to 6 months after a single injection. Isotope-marked larvae displayed variable, but generally increased physical size, indicating that enriched stable isotope labelling may have some unintended effects on larvae morphology. Consequently, transgenerational marking provides a long-term tool for marking the offspring of M. splendida to disentangle their patterns of survivorship and dispersal, with the caveat that such studies should be interpreted in light of potential isotope-related changes in offspring morphology. Understanding the biology of fish is vital to successful conservation and management, yet studying fish larvae in the wild is difficult due to their small size. This study found that marking of eastern rainbowfish larvae was possible by injecting their mothers with enriched stable barium and strontium isotopes. This technique will facilitate research on the movement of rainbowfish larvae in tropical stream networks. [ABSTRACT FROM AUTHOR]

Highlights: [•] Deccan giant plagioclase crystals show strong zoning in Sr-isotopes. [•] Diffusion modeling of zoning profiles gives a growth rate of 2.03×10−10 cms−1. [•] We calculate a duration of 21,000years for the Deccan Western Ghats eruption. [•] Short duration supports a global environmental impact due to Deccan eruption. [•] Short duration does not support long crustal residence times for Deccan magmas. [ABSTRACT FROM AUTHOR]

The Tanjianshan Group, which was previously divided into a, b, c and d formations, has been controversial for a long time. It mainly distributes in the northern margin of Qaidam Basin and is an important early Paleozoic greenschist facies metamorphic volcanic sedimentary rock formation. Detailed field investigation and zircon LA-ICPMS U-Pb dating of the key strata suggest that the original lower part of a Formation (a-1) versus the original middle upper of d Formation (d-3 and d-4), the original upper part of a Formation (a-2) and b Formation versus the original lower part of d Formation (d-1 and d-2) of Tanjianshan Group are contemporaneous heterotopic facies volcanicclasolite deposit, respectively. The former formations formed during the middle-late Ordovician (463-458 Ma), while the latter ones formed in the late Ordovician (about 445 Ma). The original c formation of Tanjianshan Group, which formed after 430 Ma, is similar to the Maoniushan Formation of Kunlun Mountains and north Qaidam Basin. According to the rules of stratigraphic division and naming, new stratum formations of Tanjianshan Group are re-built and divided into Duancenggou (O1-2 td), Zhongjiangou (O2-3 tz) and Xitieshan (O3 tx) formations. The original c Formation is separated from Tanjianshan Group and is renamed as the Wuminggou Formation (S3-D1 w), which shows a discordant contact with underlying Tanjianshan Group and overlying Amunike Formation (D3 a). The zircon U-Pb age frequency spectrogram of Tanjianshan Group indicates three prominent peaks of 430 Ma, 460 Ma and 908 Ma, which is consistent with the metamorphic and magmatic crystallization ages obtained from para- and orthogneisses in north Qaidam HP-UHP metamorphic belt, implying that strong Caledonian and Jinningian tectonic and magmatic events have ever happened in North Qaidam. [ABSTRACT FROM AUTHOR]

This work describes the chemical and mineralogical characteristics of historic pozzolanic lime mortars and modern cement mortars sampled from the Nur Jahan Tomb in Shahdara complex, Lahore, Pakistan. The mortars were studied through petrographic (polarized optical microscopy), mineralogical (XRD) and elemental (SEM-EDS, XRF) analyses. Crushed brick as pozzolanic additive created hydraulic mortars in the Mughal and British period. We also detected the prevalent use of cement-based mortar for the repairs. These compositional differences highlight the complexity of hydration processes. The formation of different hydration products in historic and modern mortars makes them incompatible and further accelerated deterioration and loss of historic fabric. [ABSTRACT FROM AUTHOR]

Precise and accurate U–Pb LA–ICPMS dating of many U-bearing accessory minerals (e.g. apatite, allanite, titanite and rutile) is often compromised by common Pb. LA–ICPMS dating of these U-bearing accessory phases typically requires a matrix-matched standard, and data reduction is often complicated by variable incorporation of common Pb not only into the unknowns but also particularly into the reference material. We present here a general approach to common Pb correction in U–Pb LA–ICP–MS dating using a modified version of the VizualAge U–Pb data reduction package for Iolite (VizualAge_UcomPbine). The key feature of the method is that it can correct for variable amounts of common Pb in any U–Pb accessory mineral standard as long as the standard is concordant in the U/Pb (and Th/Pb) systems following common Pb correction. Common Pb correction of the age standard can be undertaken using either the 204Pb, 207Pb or 208Pb(no Th) methods, and the approach can be applied to raw data files from all widely used modern multi-collector and single-collector ICPMS instruments. VizualAge_UcomPbine first applies a common Pb correction to the user-selected age standard integrations and then fits session-wide “model” U–Pb fractionation curves to the time-resolved U–Pb standard data. This downhole fractionation model is applied to the unknowns and sample-standard bracketing (using a user-specified interpolation method) is used to calculate final isotopic ratios and ages. 204Pb- and 208Pb(no Th)-corrected concordia diagrams and 204Pb-, 207Pb- and 208Pb(no Th)-corrected age channels can be calculated for user-specified initial Pb ratio(s). All other conventional common Pb correction methods (e.g. intercept or isochron methods on co-genetic analyses) can be performed offline. The approach was tested on apatite and titanite age standards (for which there are independent constraints on the U–Pb crystallization age) using a Thermo Scientific iCAP-Qc (Q–ICP–MS) coupled to a Photon Machines Analyte Excite 193nm ArF Excimer laser. Madagascar apatite, OLT1 titanite and R10 rutile were used as primary standards and were corrected for variable common Pb using the new VizualAge_UcomPbine DRS. The secondary Durango (31.44±0.18Ma) apatite standard yielded a U–Pb TW concordia intercept age of 31.97±0.59Ma (MSWD=1.09; primary standard corrected by the 207Pb-method) and a U–Pb concordia age of 31.82±0.40Ma (MSWD=1.4; primary standard corrected by the 204Pb-method). McClure Mountain (523.51±1.47Ma) yielded a U–Pb TW concordia intercept age of 524.5±3.7Ma (MSWD=0.72) while the Fish Canyon Tuff (28.201±0.046Ma) and Khan (522.2±2.2Ma) titanite standards yielded U–Pb TW concordia intercept ages of 28.78±0.41Ma (MSWD=1.4) and 520.9±3.9Ma (MSWD=4.2) respectively. The suitability of the 208Pb(no Th)-correction is demonstrated by the agreement between a U–Pb TW concordia intercept age of 452.6±4.7Ma (MSWD=0.89) and a 208Pb(no Th)-corrected TW concordia age of 448.6±4.5Ma (MSWD=1.4) on a c. 450Ma rutile which exhibits variable incorporation of common Pb. A range of LA–ICPMS U–Pb dating applications are presented and include U–Pb dating of apatite from >3.8Ga gneisses from Akilia, SW Greenland. These apatites host 13C-depleted graphite inclusions that are interpreted as biogenic in origin and representing the oldest indications of life on Earth. The U–Pb age profiles on single apatite grains presented here are characteristic of Pb loss by volume diffusion with core–rim age differences of up to 300Ma. These data explain the scatter and poor precision of earlier U–Pb apatite age determinations on Akilia apatite. Other LA–ICPMS dating applications include U–Pb apatite dating as a rapid method for determining the age of mafic intrusions, U–Pb titanite and apatite dating of ash fall tuffs, determining temperature–time histories using multiple U–Pb thermochronometers and improving concordance in LA–ICPMS primary zircon standard datasets by analysing young, common Pb-bearing primary zircon standards that have not accumulated significant radiation damage. [ABSTRACT FROM AUTHOR]

Abstract: The hydrothermal Mn–Fe–As vein mineralization at Sailauf (Germany) hosts a complex sequence of oxide and carbonate minerals that record a protracted fluid history. The mineralization is related to a major unconformity that separates Permian (Zechstein) sedimentary rocks from underlying Variscan crystalline basement. The hydrothermal veins contain two principal mineralization stages, which are Mn oxides associated with calcite and hematite associated with Mn-calcite. The fluid evolution of the hydrothermal system has been reconstructed from fluid inclusion petrography, microthermometry, and LA-ICPMS microanalysis, coupled with stable isotope geochemistry of carbonate and oxide minerals. The fluid inclusions are high salinity sodic–calcic brines and the bulk fluid properties show no major differences between the Mn oxide and the hematite stage. LA-ICPMS analysis of major and trace elements demonstrates that the mineralization formed from chemically distinct fluid pulses characterized by variations in their K, Li, B, Pb and Zn concentrations. The fluid that precipitated the Mn oxide stage has anomalous Pb/Zn and Li/B ratios, which closely resemble fluids found in fracture fillings in red beds of the Permian Rotliegend basin. By contrast, the fluids associated with the hematite stage have Pb/Zn and Li/B ratios typical of crustal fluids that were derived from interaction with crystalline basement. Both fluids possess characteristic element ratios including Cl/Br, but variable absolute concentrations of most metals. This suggests that both fluids were modified by mixing with a common metal-depleted brine that had a similar Cl/Br ratio, most likely a formation water from the overlying Zechstein sedimentary rocks. The Sailauf mineralization provides insight into the protracted post-Variscan fluid evolution at the basement–cover interface. The compositionally anomalous fluid that precipitated the Mn oxides is comparable to brines derived from interaction with red beds and likely represents the ore fluid of Kupferschiefer-type sediment-hosted Cu deposits. Conversely, the fluid that deposited the hematite mineralization resembles fluids that typically form basement- and sediment-hosted Pb–Zn deposits. [Copyright &y& Elsevier]

Trace elements and stable isotopes (δ13C and δ15C) in deep-sea coral have been used as proxies to reconstruct past climate, and to investigate food web structure. However, there is a paucity of information regarding the effect of preservation on the chemical integrity of archived coral. In this study a live-caught colony of Bamboo coral (southern Australia), genus (Lepidisis), was sectioned into three pieces and stored for approximately one year to investigate the influence of preservation in ethanol and preservation in seawater, that mimics the early stages of fossilization, against a dry preserved control. Storage and preservation have no significant effect on the isotopic signature of Δ14C, bulk δ15C, δ15C and δ13C of individual amino acids, or C:N in the fibrillar protein matrix, with the only offset (~0.2‰) being observed in part of the δ13C record. In the high-magnesium calcite lattice Ba/Ca appears to be significantly different after storage in ethanol, whereas Δ14C, B/Ca, Mg/Ca, Sr/Ca, and U/Ca remain largely unaltered. Possible mechanisms responsible for these observed differences center around the decomposition, or contamination, by organics and we recommend further investigation, and caution when comparing samples with differing preservation histories. [ABSTRACT FROM AUTHOR]

The Solonker suture zone of the Central Asian Orogenic Belt (CAOB) records the final closure of the Paleo-Asian Ocean. The nature and timing of final collision along the Solonker suture has long been controversial, partly because of an incomplete record of isotopic ages and differing interpretations of the geological environments of key tectonic units. The Xilin Gol Complex, consisting of strongly deformed gneisses, schists and amphibolites, is such a key tectonic unit within the CAOB. Lenticular or quasi-lamellar amphibolites are dispersed throughout the complex, intercalated with biotite-plagioclase gneiss. Both rock types experienced amphibolite-facies metamorphism. The protolith of the amphibolite is a basic rock that intruded into the biotite-plagioclase gneiss at 319 ± 4 Ma based on LA-ICPMS zircon U-Pb dating. The basic intrusion was sourced from a modified magma that experienced crystal fractionation and was admixed with slab-derived fluids. The slab-derived fluids, which formed during Early Paleozoic oceanic subduction along the north-dipping Sonidzuoqi-Xilinhot subduction zone, mixed with the magma source and produced subduction-related geochemical signatures superimposed on volcanic arc chemistry. After Early Paleozoic oceanic subduction and arc-continent collision, a transient stage of extension occurred between 313 and 280 Ma in the Sonidzuoqi-Xilinhot area. Deformation and recrystallization during the switch from compression to extension and reheating by the later magmatic intrusions reset the isotope systems of minerals in the Xilin Gol Complex, recorded by a 312.2 ± 1.5 Ma biotite Ar/Ar age from biotite-plagioclase gneiss, a 309 ± 12 Ma zircon intercept age and a 307.5 ± 3.5 Ma hornblende Ar/Ar age from amphibolites in the complex. There was an arc/forearc-related marine basin at the southern margin of the Xilin Gol Complex during the Permian. The closure of the oceanic basin led to Late Paleozoic-Middle Triassic north-dipping subduction beneath the Xilin Gol Complex and induced the amphibolite-facies metamorphism of the complex. The final suturing of the Solonker zone occurred from 269 to 231 Ma. This latest amphibolite-facies metamorphism with pressures of 0.31-0.39 GPa and temperatures of 620-660 °C was recorded at 263.4 ± 1.4 Ma to the Xilin Gol Complex, as indicated by the hornblende Ar/Ar age from the amphibolites, as well as several zircon ages of 260 ± 3-231 ± 3 Ma. The Xilin Gol Complex documented the progressive accretion of a single, long-lived subduction system at the southern margin of the south Mongolian microcontinent from the Early Paleozoic (~452 Ma) to Middle Triassic (~231 Ma). The CAOB shows protracted collision prior to final suturing. [ABSTRACT FROM AUTHOR]

High spatial resolution, quantitative chemical imaging is of importance to various scientific communities, however high spatial resolution and robust quantification are not trivial to attain at the same time. In order to achieve microscopic chemical imaging with enhanced quantification capabilities, the current study links the independent and complementary advantages of two micro-analytical techniques – Synchrotron Radiation-based micro X-ray Fluorescence (SR-microXRF) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICPMS). A cross-calibration approach is established between these two techniques and validated by one experimental demonstration. In the presented test case, the diffusion pattern of trace level Cs migrating into a heterogeneous geological medium is imaged quantitatively with high spatial resolution. The one-dimensional line scans and the two-dimensional chemical images reveal two distinct types of geochemical domains: calcium carbonate rich domains and clay rich domains. During the diffusion, Cs shows a much higher interfacial reactivity within the clay rich domain, and turns out to be nearly non-reactive in the calcium carbonate domains. Such information obtained on the micrometer scale improves our chemical knowledge concerning reactive solute transport mechanism in heterogeneous media. Related to the chosen demonstration study, the outcome of the quantitative, microscopic chemical imaging contributes to a refined safety assessment of potential host rock materials for deep-geological nuclear waste storage repositories.

[Display omitted] • In-situ scheelite TE and 87Sr/86Sr distinguish two types of W mineralisation. • Scheelite compositions reflect the source of the fluids. • Proximal, non-economic scheelite occurrences have local controls on composition. • Distally-sourced W deposits form along crustal discontinuities • Distally-sourced W-bearing fluids homogenise with ascent through the crust. The Otago Schist in New Zealand hosts orogenic tungsten (W) mineralization in two types. Proximally-sourced ("proximal") mineralization in sub- to lower-greenschist facies Mesozoic metasedimentary rocks within the northern flank of the Otago Schist Belt comprise quartz-calcite veins with minor scheelite and few sulfides. Distally-sourced ("distal") deposits are hosted in major crustal discontinuities within Mesozoic sub-greenschist to upper-greenschist facies metasedimentary rocks and are associated with abundant sulfides ± Au. In-situ trace element (particularly REE, Sr, Mo, Na, As) and in-situ 87Sr/86Sr compositions of scheelite show the scheelite occurring in these different mineralization types to be geochemically distinct. Proximal occurrences are characterised by scheelite with both heterogenous trace element and Sr isotope compositions displaying variations that can be linked to different veins, host rock types and scheelite generations. In contrast, scheelite within distal scheelite deposits tends to have fairly homogenous trace element and Sr isotopic ratios at the deposit to grain scale. The heterogenous compositions of proximal occurrences represent local derivation of diverse components from the sub-millimetre to meter scales and small extents of fluid flow, which resulted in a high sensitivity to sources and local rock compositions and thus limited large-scale equilibration of elemental and isotopic systematics within the scheelite they contain. The larger distal deposits formed by regional leaching by metamorphic fluids, probably at the greenschist-amphibolite facies boundary, followed by homogenisation as they ascended through the crust and leading to deposition of scheelite with rather uniform chemical characteristics. Our data re-enforce the model that tungsten mobility in the Otago Schist involved local-scale mobilisation of W in the shallow crust by breakdown of detrital rutile and scheelite at low metamorphic grade. Burial of these veined scheelite-bearing rocks to temperatures of ∼500 °C enabled remobilisation of W by metamorphic fluids, concurrent with scavenging of Au, As and S, followed by return of the metal-bearing fluids towards mid to upper crustal levels, where they precipitated scheelite. [ABSTRACT FROM AUTHOR]

Non-invasive methods are needed to enable indirect observation of vulnerable migratory fish populations across their life cycle and spatial distribution. Microchemistry data, such as trace element (TE) concentrations, collected non-invasively from the biomineral in fish scales can be used to characterize fish life history (habitat usage, fish provenance). However, scales are generally underutilized in microchemistry studies, due to conflicting evidence regarding the temporal stability of their composition. Some studies have found TE concentrations from scales are stable and reflect environmental conditions and habitat usage through time, while others have found that TE concentrations can change significantly after deposition in fish which have undertaken migration or spawning. Furthermore, validating TE proxies, such as fish scales, is extremely challenging for vulnerable populations because they have notoriously low survival rates in the wild, making tag and recapture experiments incredibly difficult. This study aimed to directly quantify changes in TE concentrations in scales collected from Atlantic salmon (Salmo salar , L.) at the juvenile and adult life stage. Over 1800 wild Atlantic salmon were tagged with passive integrated tags and, remarkably, 3 fish were successfully recaptured as adults. Individuals were sampled twice in the freshwater as juveniles, and again upon recapture during their return migration as adults. Scales were analyzed for concentrations of Ba, Sr, Mg, Mn, Fe, and Zn, using Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICPMS). Mixed effects models found significant changes in TE concentrations, between the juvenile scale and freshwater portion of the adult scale for all elements. Post depositional alteration may be caused by continued crystallization of scale apatite after migration, or scale reabsorption during the pre-spawning period. Future work could investigate the TE signal of fish recaptured at sea, to determine exactly when TE concentrations become modified. [ABSTRACT FROM AUTHOR]

Abstract: Cobalt blue glass has long now been recognised as characterised by a distinct compositional signature within the typical compositional range of Late Bronze Age glass. More recently, a copper-rich variation of cobalt blue glass has been seen throughout Egypt and the Mycenaean world. This paper discusses and defines this glass type based on trace elemental data, examines whether this lighter-shaded cobalt blue glass is a natural or an anthropogenic variant of cobalt blue glass, and identifies its likely production in Egypt. It investigates the role of this type of glass, particularly with regard to the distribution pattern and the significance of its prevalence in the Mycenaean mainland and the Aegean. [Copyright &y& Elsevier]

Intra-test variability in Mg/Ca and other (trace) elements within large benthic foraminifera (LBF) of the family Nummulitidae have been investigated using laser-ablation inductively-coupled plasma mass spectrometry (LA-ICPMS). These foraminifera have a longevity and size facilitating seasonal proxy retrieval and a depth distribution similar to ‘surface-dwelling’ planktic foraminifera. Coupled with their abundance in climatically important periods such as the Paleogene, this means that this family of foraminifera are an important but under-utilised source of palaeoclimatic information. We have calibrated the relationship between Mg/Ca and temperature in modern Operculina ammonoides and observe a increase in Mg/Ca °C−1. O. ammonoides is the nearest living relative of the abundant Eocene genus Nummulites, enabling us to reconstruct mid-Eocene tropical sea surface temperature seasonality by applying our calibration to fossil Nummulites djokdjokartae from Java. Our results indicate a 5–6 °C annual temperature range, implying greater than modern seasonality in the mid-Eocene (Bartonian). This is consistent with seasonal surface ocean cooling facilitated by enhanced Eocene tropical cyclone-induced upper ocean mixing, as suggested by recent modelling results. Analyses of fossil N. djokdjokartae and Operculina sp. from the same stratigraphic interval demonstrate that environmental controls on proxy distribution coefficients are the same for these two genera, within error. Using previously published test–seawater alkaline earth metal distribution coefficients derived from an LBF of the same family (Raitzsch et al., 2010) and inorganic calcite, with appropriate correction systematics for secular Mg/Casw variation (Evans and Müller, 2012), we use our fossil data to produce a more accurate foraminifera-based Mg/Casw reconstruction and an estimate of seawater Sr/Ca. We demonstrate that mid-Eocene Mg/Casw was , which is in contrast to the model most commonly used to correct deep-time Mg/Ca data from foraminifera, but in agreement with most other Paleogene proxy and model data. This indicates that Mg/Casw has undergone a substantial ( ) rise over the last . [ABSTRACT FROM AUTHOR]

The paper reports newly obtained data on the geochronology of the Dovyren intrusive complex and associated metarhyolites of the Inyaptuk Formation in the Synnyr Range. The data were obtained by local LA-ICPMS analysis of zircons in samples. The U-Pb age of olivine-free gabbronorite from near the roof of the Yoko-Dovyren Massif is 730 ± 6 Ma (MSWD = 1.7, n = 33, three samples) is close to the estimated age of 731 ± 4 Ma (MSWD = 1.3, n = 56, five samples) of a 200-m-thick sill beneath the pluton. These data overlap the age of recrystallized hornfels found within the massif ('charnockitoid', 723 ± 7 Ma, MSWD = 0.12, n = 10) and a dike of sulfidated gabbronorite below the bottom of the massif (725 ± 8 Ma, MSWD = 2.0, n = 15). The estimates are also consistent with the age of albite hornfels (721 ± 6 Ma, MSWD = 0.78, n = 12), which was produced in a low-temperature contact metamorphic facies of the host rocks. The average age of the Dovyren Complex is 728.4 ± 3.4 Ma (MSWD = 1.8, n = 99) based on data on the sill, near-roof gabbronorite, and 'charnockitoid') and is roughly 55 Ma older than the estimate of 673 ± 22 Ma (Sm-Nd; [13]). The U-Pb system of zircon in two quartz metaporphyre samples from the bottom portion of the Inyaptuk volcanic formation in the northeastern part of the Yoko-Dovyren Massif turns out to be disturbed. The scatter of the data points can be explained by the effect of two discrete events. The age of the first zircon population is then 729 ± 14 Ma (MSWD = 0.74, n = 8), and that of the second population is 667 ± 14 Ma (MSWD = 1.9, n = 13). The older value pertains to intrusive rocks of Dovyren, and the age of the 'rejuvenated' zircon grains corresponds to the hydrothermal-metasomatic processes, which affected the whole volcano-plutonic sequence and involved the serpentinization of the hyperbasites. This is validated by the results of Rb-Sr isotopic studies with the partial acid leaching of two serpentinized peridotite samples from the Verblyud Sill. These studies date the overprinted processes at 659 ± 5 Ma (MSWD = 1.3, n = 3). [ABSTRACT FROM AUTHOR]

Highlights: [•] Acid rock drainage prediction can be improved by better understanding mineralogy. [•] Mineralogical and microtextural analyses were integrated into kinetic tests. [•] Two size fractions were prepared from materials with diverse sulphide mineralogy. [•] Formation of secondary minerals influenced leachate chemistry. [•] Finer fraction material generally produced lower pH leachate with greater element contents. [ABSTRACT FROM AUTHOR]

The trans-Himalayan Ladakh batholith is a result of arc magmatism caused by the northward subduction of the Tethyan oceanic lithosphere below the edge of the Eurasian plate. The batholith dominantly consists of calc-alkaline I-type granitoids which are ferromagnetic in nature with the presence of magnetite as the principal carrier of magnetic susceptibility. The mesoscopic and magnetic fabric are concordant and generally vary from WNW-ESE to ENE-WSW for different intrusions of ferromagnetic granites in different parts of the batholith. Strike of magnetic fabric is roughly parallel with the regional trend of the Ladakh batholith in the present study area and is orthogonal to the direction of India-Eurasia collision. In Khardungla and Changla section, the magnetic fabric is distributed in a sigmoidal manner. It is inferred that this sigmoidal pattern is caused by shearing due to transpression induced by oblique convergence between the two plates. U-Pb zircon geochronology of a rhyolite from the southern parts of the batholith gives a crystallization age of 71.7 ± 0.6 Ma, coeval with ~68 Ma magmatism in the northern parts of the batholith. The central part of the batholith is characterized by S-type two-mica granites, which gives much younger age of magmatism at 35.5 ± 0.5 Ma. The magnetic fabric of these two-mica granites is at a high angle to the regional trend of the batholith. It is proposed that these two-mica granites were emplaced well after the cessation of subduction and arc magmatism, along fractures that developed perpendicular to the regional strike of the batholith due to shearing. [ABSTRACT FROM AUTHOR]

Abstract: Mixed-habit diamonds are a special type of crystal that form by simultaneous growth by two different mechanisms; octahedral and cuboid growth. This type of crystal growth is known to preferentially partition nitrogen into the octahedral growth sectors during growth. To identify if this fractionation occurs for any other trace element, this study applies in situ laser ablation mass spectrometry to a well-studied collection of mixed-habit diamonds. The results show high concentrations of nickel (3.6–36.4ppm) and cobalt (0.108–1.25ppm) in the cuboid sectors, whereas the octahedral sectors contain only <0.05–0.35ppm nickel and <0.014–0.03ppm cobalt. The relative enrichment of nickel in the cuboid sectors varies between 10 and 460 times. For cobalt, where the concentrations in the octahedral sector are commonly below the limit of quantification, the enrichment is estimated to be in the range of 10–100 times. There appears to be a rough linear relationship between the concentrations of the two elements in the cuboid sectors, with nickel concentrations approximately 27 times that of cobalt. This finding of nickel fractionation into the cuboid sectors is the opposite of what is seen in synthetic diamonds grown from FeNi solvents, where Ni is only found in the octahedral growth sectors. We propose that this is because the inherent lattice strain in the rough cuboid diamond growth of natural mixed-habit diamonds is greater than that in the smooth octahedral growth, making it easier to fit the large Ni and Co ions into a divacancy. In diamonds grown from metal solvents (i.e. industrial synthetic diamonds), the cube face is a smooth one, therefore the partitioning of trace elements is simply a result of the octahedral surface offering more bonding opportunities than the cube surface. Due to the extremely low concentrations of trace elements in these gem quality diamonds, many of the elements are commonly below the limit of quantification (LOQ). While we are confident that Pr, Sr, Pb, Zr, V, Cr and Zn are not fractionated by the crystal growth mechanisms of mixed-habit diamonds that affect Ni and Co, this remains to be proven for the remaining trace elements analysed. Data on the fractionation of copper are inconclusive, with 75% of data from the cuboid sectors above the LOQ and all data from the octahedral sectors below the LOQ. However, the values of the LOQ for the octahedral data are often higher than those of the cuboid data, so further investigation of Cu is necessary to confirm its behaviour. [Copyright &y& Elsevier]

Baddeleyite (ZrO2) is today recognized as the key mineral for dating the emplacement of mantle-derived igneous rocks, primarily gabbro and dolerite dykes and sills. The comment by Michard and Gasquet calls for a discussion on the significance of baddeleyite U–Pb TIMS dates of two dykes in the Bas-Drâa inlier, dated at 1381±8 and 1384±6Ma, presented in El Bahat et al. (2013-in this issue). They suggest that the U–Pb systematics were “seriously perturbed in the Bas-Drâa region” with the main argument being a lack of age matches between the ca. 1385Ma dykes in Bas-Drâa and the 2040, 1650 and 885Ma dykes in adjacent inliers to the east. To infer an older age for these dykes, as suggested by Michard and Gasquet, and explain the ca. 1385Ma TIMS results would require two separate events of perturbation, in the Mesoproterozoic and a subsequent Variscan event. However, such an alternative is improbable from basic theoretical reasoning using U–Pb isotopic systematics and our current understanding of the behaviour of baddeleyite in metamorphic systems. In addition, we present new LA-ICPMS U–Pb age data of baddeleyite from one of the dated dykes from Bas-Drâa. The new LA-ICPMS U–Pb age of 1416±7Ma is slightly but significantly older than our TIMS 1384±6Ma upper intercept age, nevertheless confirming this dyke could not correspond to any of the other mafic intrusions dated in the inliers to the east. The LA-ICPMS result also contributes to a deeper understanding on the effects of secondary processes in baddeleyite in general, and suggests a modified methodological approach for samples with complex geological histories. [ABSTRACT FROM AUTHOR]

The fluid evolution of late-metamorphic quartz vein systems in the fold-and-thrust belt of the Rhenish Massif has been studied by microthermometry and LA-ICPMS microanalysis. The quartz veins are hosted by very low-grade organic-matter-rich metasiltstones and metapelites of the Hunsrück nappe complex. The veins record two major stages of textural evolution, a massive vein filling assemblage with elongate-blocky quartz, chlorite, albite and apatite, and a later open space filling assemblage with euhedral crystals of quartz, ankerite/dolomite and minor calcite and sulfides. The euhedral quartz crystals host well-preserved fluid inclusion assemblages, which made it possible to reconstruct the chemical evolution of the fluid system with time. The fluid inclusions are all aqueous two-phase with low salinity, and three successive fluid generations record a systematic decrease in salinity from 4.7–5.3 to 3.1–3.9 and then to 1.4–1.7wt.% eqv. NaCl. The salinity decrease is paralleled by a decrease in homogenization temperatures from 210–225°C to 148–164°C and 124–139°C. Using LA-ICPMS microanalysis of individual fluid inclusions, reproducible elemental concentrations of Li, Na, K, Rb, Cs, Mg, Ca, Ba, Sr, B, Al, As, Sb, S, Cl and Br could be determined. The concentrations of the alkali metals and of boron, arsenic and antimony are correlated with the fluid salinity. Element concentrations are highest in the early fluid generation and decrease systematically in the latter two generations. The systematic changes in fluid composition (salinity, homogenization temperature and elemental concentrations) are best explained by fluid mixing between a hot metamorphic fluid of moderate salinity (that carried elevated concentrations of B, As and Sb) and a cooler dilute fluid that was of meteoric origin. The fluid evolution therefore signals deep ingression of meteoric water during late-metamorphic exhumation and uplift. The molar Cl/Br ratios of the fluid inclusions lie on a linear array that extends from close to seawater to values that are substantially below seawater. Because evaporitic sources are conspicuously absent in the shallow-water marine sequence of the Rhenish Massif, the elevated Br concentrations (and Cl/Br ratios below seawater) are best explained by fluid–rock interaction and liberation of Br from the organic matter in the metasediments. [ABSTRACT FROM AUTHOR]

The chemical composition of fluid inclusions in quartz crystals from Alpine fissure veins was determined by combination of microthermometry, Raman spectroscopy, and LA-ICPMS analysis. The veins are hosted in carbonate-bearing, organic-rich, low-grade metamorphic metapelites of the Bündnerschiefer of the eastern Central Alps (Switzerland). This strongly deformed tectonic unit is interpreted as a partly subducted accretionary wedge, on the basis of widespread carpholite assemblages that were later overprinted by lower greenschist facies metamorphism. Veins and their host rocks from two locations were studied to compare several indicators for the conditions during metamorphism, including illite crystallinity, graphite thermometry, stability of mineral assemblages, chlorite thermometry, fluid inclusion solute thermometry, and fluid inclusion isochores. Fluid inclusions are aqueous two-phase with 3.7-4.0 wt% equivalent NaCl at Thusis and 1.6-1.7 wt% at Schiers. Reproducible concentrations of Li, Na, K, Rb, Cs, Mg, Ca, Sr, Ba, B, Al, Mn, Cu, Zn, Pb, As, Sb, Cl, Br, and S could be determined for 97 fluid inclusion assemblages. Fluid and mineral geothermometry consistently indicate temperatures of 320 ± 20 °C for the host rocks at Thusis and of 250 ± 30 °C at Schiers. Combining fluid inclusion isochores with independent geothermometers results in pressure estimates of 2.8-3.8 kbar for Thusis, and of 3.3-3.4 kbar for Schiers. Pressure-temperature estimates are confirmed by pseudosection modeling. Fluid compositions and petrological modeling consistently demonstrate that chemical fluid-rock equilibrium was attained during vein formation, indicating that the fluids originated locally by metamorphic dehydration during near-isothermal decompression in a rock-buffered system. [ABSTRACT FROM AUTHOR]

Abstract: The Sailauf Mnph name="sbnd" />As vein mineralization, located in the Spessart district (central Germany), is characterized by complex hydrothermal carbonate and oxide assemblages. The mineralization is hosted by a Permian rhyolite body and is structurally related to the Variscan unconformity that separates Permian sedimentary rocks from the underlying Variscan crystalline basement. The hydrothermal vein system has been studied by optical microscopy, electron-microprobe and LA-ICPMS analysis of major and trace elements (including the REE). Four distinct mineralization stages that are characterized by diagnostic carbonate-oxide assemblages are identified, which are (1) pre-ore stage, (2) ore stage 1, (3) ore stage 2, and (4) the replacement stage. Hydrothermal carbonates show complex compositional trends in Caph name="sbnd" /> (Fe+Mg) space, and comprise calcite, Mn-calcite, Fee, Ca-rhodochrosite, and Ca-kutnahorite. Oxide assemblages are dominated by braunite and hematite, with minor amounts of manganite and hausmannite. The mineralization is enriched in a distinct suite of trace elements, including As, W, Pb, Zn and Cu. Analysis of the paragenetic evolution, in conjunction with the major and trace element data, allows to reconstruct the fluid evolution of the hydrothermal system. The first order change in mineralogy between the two main ore stages (Mn oxides and calcite evolving into hematite and Mn-rich calcite) records a pronounced shift in fluid pH and silica activity of the system. This interpretation is also supported by variations in the behavior of Ce in different carbonate generations. The late stage replacement carbonates relate to destabilization of the primary ore assemblages. The distinct geological setting immediately below the Permian unconformity, in conjunction with the mineralogical and chemical data, suggests that dynamic fluid mixing processes involving basement-derived brines and more shallow groundwaters were important in the formation of the Sailauf Mnph name="sbnd" />As mineralization. The significant enrichment in the Ash name="sbnd" />Pbph name="sbnd" />Cu element suite resembles that of other Mnts, and points to felsic lithologies as the main metal source of the mineralization. [Copyright &y& Elsevier]

Abstract: Early Miocene corals (Siderastrea conferta and Montastraea limbata) from the Paraguaná Peninsula, Venezuela and a modern coral (S. radians) from Bermuda were examined in order to quantitatively assess the effect of skeletal preservation on element/Ca proxies used for palaeo-environmental reconstructions. The biostratigraphic age (Burdigalian) of the corals was confirmed via Sr isotope stratigraphy to 16.5±0.4Ma. Light and scanning electron microscopy revealed the presence of aragonite and calcite cements in both fossil and modern corals, but brucite cements were found only in the modern coral. Cement distribution is very heterogeneous, resulting in zones of excellent preservation juxtaposed with less well preserved regions in both modern and fossil coral. Oil-filled pore spaces were noted in the fossil specimens. Targeted LA–ICPMS depth profile analyses showed significant differences in Sr/Ca, Mg/Ca, B/Ca, Ba/Ca and U/Ca in aragonite and calcite cements compared to primary skeletal aragonite. Increased Sr/Ca and decreased Mg/Ca ratios were found in aragonite cements compared to skeletal aragonite, whereas in calcite cements these trends were reversed. B/Ca ratios were lower in both aragonite and calcite cements compared to primary aragonite. Estimates of the effect of 1% contamination by aragonite cements on coral Sr/Ca, Mg/Ca, B/Ca and U/Ca palaeo-sea-surface-temperature reconstructions for the fossil corals produced anomalies of −1.2°C, −0.2°C, +0.3°C and −0.1°C respectively. Similar percentage calcite cement contamination produced temperature anomalies of +1.7°C, +2.7°C, +0.3°C and −0.1°C. Because of both highly elevated and depleted Ba/Ca signatures in aragonite and calcite cements respectively, care has to be exercised when reconstructing past flood or upwelling events from fossil corals. When using targeted spatially-resolved analysis, well-preserved early Miocene corals may overall yield reliable ‘deep-time’ palaeo-proxy information in much the same way as commonly utilised Holo/Pleistocene corals. [Copyright &y& Elsevier]

Abstract: Eastern Srednogorie in Bulgaria is the widest segment of an extensive magmatic arc that formed by convergence of Africa and Europe during Mesozoic to Tertiary times. Northward subduction of the Tethys Ocean beneath Europe in the Late Cretaceous gave rise to a broad range of basaltic to more evolved magmas with locally associated Cu–Au mineralization along this arc. We used U–Pb geochronology of single zircons to constrain the temporal evolution of the Upper Cretaceous magmatism and the age of basement rocks through which the magmas were emplaced in this arc segment. High precision isotope dilution-thermal ionization mass spectrometry (ID-TIMS) was combined with laser ablation-inductively coupled plasma mass spectrometry (LA–ICPMS) for spatial resolution within single zircon grains. Three tectono-magmatic regions are distinguished from north to south within Eastern Srednogorie: East Balkan, Yambol–Burgas and Strandzha. Late Cretaceous magmatic activity started at ~92Ma in the northernmost East Balkan region, based on stratigraphic evidence and limited geochronology, with the emplacement of minor shallow intrusions and volcanic rocks onto pre-Cretaceous basement. In the southernmost Strandzha region, magmatism was initiated at ~86Ma with emplacement of gabbroic to dioritic intrusions and related dikes into metamorphic basement rocks that have previously been overprinted by Jurassic–Lower Cretaceous metamorphism. The Yambol–Burgas region is an extensional basin between the East Balkan and the Strandzha regions, which broadens and deepens toward the Black Sea further east and is filled with a thick pile of marine sediments and submarine extrusive volcanic rocks accompanied by coeval intrusions. This dominantly mafic magmatism in the intermediate Yambol–Burgas region commenced at ~81Ma and produced large volumes of potassium-rich magma until ~78Ma. These shoshonitic to ultrapotassic basaltic to intermediate magmas formed by differentiation of ankaramitic (high Ca) parental melts, produced from partial remelting of amphibole clinopyroxenites upon interaction with subduction-modified mantle wedge melts, according to earlier petrological studies. This peak of dominantly extrusive activity in the Yambol–Burgas region extended into the Strandzha region further south, in the form of numerous tholeiitic, calc-alkaline and high-K intrusions emplaced in the same time period between 81 and 78Ma. Granitic rocks from exposed basement of Eastern Srednogorie zone are dated as Permian/Carboniferous (~275–300Ma). Zircons with similar ages occur in Upper Cretaceous rocks from the East Balkan and Strandzha regions, indicating local incorporation as xenocrysts. In contrast, magmatic rocks from the intermediate Yambol–Burgas region contain mostly Ordovician (~460Ma) or older inherited zircons, suggesting a either a different basement history or, more likely, a different level of magma storage and crustal assimilation. Integrating these geochronological results with a synthesis of the regional geology, we propose a two-stage geodynamic evolution for the Eastern Srednogorie segment of the Tethyan arc. The earlier stage of normal arc magmatism was driven by a southward slab retreat, which formed the ~92Ma calc-alkaline to high-K shallow intrusions and volcanics in the north (East Balkan), 87–86Ma old tholeiitic and calc-alkaline intrusions in the south (Strandzha), and the voluminous 81–78Ma old gabbroic to granitic intrusions with predominantly calc-alkaline to high-K composition throughout the Strandzha region. This stage continued westward into the Central Srednogorie zone, where the southward younging of calc-alkaline magmatism correlates well with an increased input of primitive mantle melts, indicating asthenospheric incursion into a widening mantle wedge as a result of slab roll-back. The second stage proceeded in the Eastern Srednogorie zone only, where more extreme extension associated with the opening of the Black Sea back-arc basin led to the formation of an intra-arc rift in the Yambol–Burgas region, which now separates the East Balkan region from the Strandzha region. In this extensional environment, crustal thinning lead to decompression and increased heat flow, facilitating large-scale melting of lower crustal rocks and the formation of 81–78Ma magmas. The unusual calcic composition of the parent magmas, their isotopic character and distinct xenocrystic population are consistent with a component of re-melting of hydrous lower-crustal cumulates, which probably formed in part during the first stage of the evolving arc. [Copyright &y& Elsevier]

This article concerns application of cathodoluminescence (CL) spectroscopy to volcanic quartz and its utility in assessing variation in trace quantities of Ti within individual crystals. CL spectroscopy provides useful details of intragrain compositional variability and structure but generally limited quantitative information on element abundances. Microbeam analysis can provide such information but is time-consuming and costly, particularly if large numbers of analyses are required. To maximize advantages of both approaches, natural and synthetic quartz crystals were studied using high-resolution hyperspectral CL imaging (1.2–5.0 eV range) combined with analysis via laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). Spectral intensities can be deconvolved into three principal contributions (1.93, 2.19, and 2.72 eV), for which intensity of the latter peak was found to correlate directly with Ti concentration. Quantitative maps of Ti variation can be produced by calibration of the CL spectral data against relatively few analytical points. Such maps provide useful information concerning intragrain zoning or heterogeneity of Ti contents with the sensitivity of LA-ICPMS analysis and spatial resolution of electron microprobe analysis. [ABSTRACT FROM PUBLISHER]

Abstract: Major and trace-element microanalyses of the main minerals from the 610Ma Pedra Branca Syenite, southeast Brazil, allow inferences on intensive parameters of magmatic crystallization and on the partition of trace-elements among these minerals, with important implications for the petrogenetic evolution of the pluton. Two main syenite types make up the pluton, a quartz-free syenite with tabular alkali feldspar (laminated silica-saturated syenite, LSS, with Na-rich augite+phlogopite+hematite+magnetite+titanite+apatite) and a quartz-bearing syenite (laminated silica-oversaturated syenite, LSO, with scarce corroded plagioclase plus diopside+biotite±hornblende+ilmenite±magnetite+titanite+apatite). Both types share a remarkable enrichment in incompatible elements as K, Ba, Sr, P and LREE. Apatite saturation temperatures of ~1060–1090°C are the best estimates of liquidus, whereas the pressure of emplacement, based on Al-in-hornblende barometry, is estimated as 3.3 to 4.8kbar. Although both units crystallized under oxidizing conditions, oxygen fugacity was probably higher in LSS, as shown by higher mg# of the mafic minerals and higher hematite contents in Hem-Ilmss. In contrast with the Ca-bearing alkali-feldspar from LSO, which hosts most of the whole-rock Sr and Pb, virtually Ca-free alkali-feldspar from LSS hosts ~50% of whole-rock Sr and ~80% of Pb, the remainder of these elements being shared by apatite, pyroxene and titanite. This contrast reflects a strong crystal-chemical control, whereby a higher proportion of an element with similar ratio and charge (Ca2+) enhances the residence of Sr and Pb in the M-site of alkali feldspar. The more alkaline character of the LSS magma is inferred to have inhibited zircon saturation; Zr+Hf remained in solution until late in the crystallization, and were mostly accommodated in the structure of Ca–Na pyroxene and titanite, which are one order of magnitude richer in these elements compared to the same minerals in LSO, where most of Zr and Hf are inferred to reside in zircon. The REE, Th and U reside mostly in titanite and apatite; D(REE)Tit/Ap raises steadily from 1 to 6 from La to Tb then remains constant up to Lu in the LSO sample; these values are about half as much in the LSS sample, where lower contents of incompatible elements in titanite are attributed to its greater modal abundance and earlier crystallization. [Copyright &y& Elsevier]

Abstract: The origin of salinity in crustal fluids can be deduced from their Cl, Br and Na concentrations and associated Cl/Br and Na/Br ratios. Here, a protocol for quantitative analysis of Cl, Br and Na concentration in individual fluid inclusions of variable size, bulk salinity, Cl, Br and Na contents is presented. It combines microthermometry and laser ablation — inductively coupled plasma mass spectrometry (LA-ICPMS) analysis. The method is based on: (i) microthermometric measurement of ice melting, hydrate melting, halite dissolution and sylvite dissolution temperatures in fluid inclusions; (ii) calibration of LA-ICPMS signals of Br by analyzing Na–Br–Cl standard solutions loaded in silica glass capillaries; (iii) calculation of solute (Cl, Na, Ca, K, Mg) concentration based on LA-ICPMS intensities and the Pitzer thermodynamic model (for inclusions of salinity below 23wt.% equivalent NaCl), or a charge-balance approach (for higher salinity inclusions) and (iv) calculation of uncertainty on Cl, Br and Na concentration and Cl/Br and Na/Br ratios in the fluid. This method is applied to natural fluid inclusions with variable Cl, Br and Na contents as previously determined by microthermometry and bulk crush-leach coupled with ion chromatography analysis. The studied materials consist of: i) low-salinity inclusions from Alpine quartz veins and ii) high-salinity inclusions from the Trimouns talc deposit and from Athabasca Basin uranium deposits. Molar Cl/Br and Na/Br ratios range from 140±50 to 1200±400 and 17±6 to 880±290 in the analyzed inclusions. The calculated uncertainty on Cl/Br and Na/Br ratios in individual fluid inclusions is between 30 and 38%, regardless of the salinity. It appears that the analysis of individual inclusions coupled with uncertainty calculation allows the identification of significant variation of Cl/Br and Na/Br ratios within individual samples that could not be identified from previous bulk crush-leach and ion chromatography analyses. Because Br is a minor solute (molar Cl/Br is between ~100 and ~10000 in most crustal fluids), and because of its high first ionization energy, the determination of Br concentration in individual inclusion by combining microthermometry and LA-ICPMS analysis is most readily achievable for large (>50μm in diameter) inclusions. For smaller inclusions (10 to 50μm in diameter), the applicability of the present method is more sensitive to the Br concentration. [Copyright &y& Elsevier]

Abstract: We present LA-ICPMS U-Pb zircon ages and field data from the rift-related, Cryogenian-aged Toekems Sub-basin in the south-western Welwitschia Inlier on the southern margin of the Congo Craton in the Damara Belt (Northern Margin Zone), Namibia. The Toekems Sub-basin comprises a wedge up to 730m-thick of dominantly clastic sediments between Palaeoproterozoic basement and the Cryogenian Abenab Subgroup. The base of the succession is a distinct coarsening upward breccia that contains entirely basement clasts. The overlying strata consist of mixed polymictic conglomerates, debris flow diamictites, tuffs, volcaniclastic sandstone, siltstone, and minor carbonates. A pegmatite cross-cutting the basal breccia has yielded a mean weighted average 206Pb/238U age of 763±5Ma. This age statistically overlaps the nearby 756±2Ma Oas Syenite and 760±1Ma ash bed in the Ombombo Subgroup to the north and is somewhat older than the ca. 746Ma Naauwpoort Volcanics, which underlie the glacigenic Chuos Formation in the Summas Mountains to the south. This indicates that initial sedimentation in the Toekems Sub-basin began prior to 763Ma. However, the presence of laminae-deforming lonestones, iron-formation and the stratigraphic position relative to the overlying Rasthof cap carbonate suggest that most of the succession is glacially-influenced, and hence correlates with the Chuos Formation. These results imply a significant disconformity beneath the Naauwpoort Volcanics and suggest multi-phase rifting during the breakup of south-western Congo Craton from Rodinia. [Copyright &y& Elsevier]

Abstract: The Estremoz Anticline in the Ossa-Morena Zone (SW Iberia) includes upper Ediacaran detrital rocks unconformably overlain by lower Cambrian detrital and carbonate rocks. The spectra of detrital zircon U–Pb ages dominated by Cryogenian and Ediacaran ages (with a typical gap in Mesoproterozoic ages) of the upper Ediacaran greywackes and lower Cambrian arkosic sandstones indicate provenance from sources placed near or at the North-Gondwana margin. These late Ediacaran and early Cambrian basins developed in a paleoposition close to the West African Craton and related to a long-lived Neoproterozoic magmatism (c. 850–700Ma — Pan-African suture; c. 700–635Ma — early Cadomian arc; and c. 635–545Ma — late Cadomian arc). The rhyolites of the Volcanic–Sedimentary Complex of Estremoz whose stratigraphic position so far has been a controversy, yielded an upper Cambrian age (Furongian) at about 499Ma indicating that carbonate production was episodic in SW Iberia during the Cambrian. This new evidence should be taken into account in the reshaping of paleogeographic reconstruction models that have erroneously insisted on placing Iberia at southerly cold water higher latitudes (>60°S) during the Furongian. [Copyright &y& Elsevier]

Titanite is an ideal mineral for U-Pb isotopic dating because of its relatively high U, Th and Pb contents. Here, we developed a technique for U-Pb dating of titanite using the 193 nm ArF laser-ablation system and Agilent 7500a Q-ICP-MS. Standards of titanite (BLR-1 and OLT-1) and zircon (91500 and GJ-1) were dated using single spot and line raster scan analytical methods. To check the matrix effect, titanite (BLR-1) and zircon (91500) standards were analyzed as the external standards. The weighted mean Pb/U ages of OLT-1 titanite are 1015±5 Ma (2 σ, n=24) and 1017±6 Ma (2 σ, n=24) by single spot and line raster scan analyses, respectively, using BLR-1 titanite as the external standard. These ages are consistent with its reference age of about 1014 Ma. However, using 91500 zircon as the external standard, the weighted mean Pb/U ages are 917±4 Ma (2 σ, n=24) and 927±5 Ma (2 σ, n=24) for BLR-1 titanite, and 891±4 Ma (2 σ, n=24) and 901±5 Ma (2 σ, n=24) for OLT-1 titanite by single spot and line raster scan analyses, respectively. It is evident that these ages are ∼12% younger than their reference values. Our results reveal that significant matrix effect does exist between different kinds of minerals during LA-ICPMS U-Pb age determination, whereas it is insignificant between same minerals. Therefore, same mineral must be used as the external standard for fractionation corrections during in situ LA-ICPMS U-Pb age analysis. In addition, we determined U-Pb ages for titanites from the Early Cretaceous Fangshan pluton, which indicates a rapid cooling history of this pluton. [ABSTRACT FROM AUTHOR]

Chironex fleckeri medusae metamorphose from sessile polyps, possibly in estuarine environments, and migrate into coastal waters. The objective of this study was to critically test the anecdotal paradigm that the medusae originate in lower salinity waters. Laser-ablation inductively coupled plasma-mass spectrometry was used on C. fleckeri statoliths to test the hypothesis that C. fleckeri medusae only originate from low salinity tidal creeks. Statoliths were extracted from C. fleckeri medusae collected from multiple locations around tropical Australia. Strontium:Calcium (Sr:Ca) ratios were used as a proxy for salinity; where salinity remained consistent in the field, the ratio was compared with the elemental chemistry in statoliths. Sr:Ca ratios of the statolith core and edge zones showed some evidence that medusae originated in lower Sr:Ca levels and moved to higher levels as expected under the hypothesis. That pattern was not consistent, however, and sources from multiple oceanographic regimes were indicated. Core-to-edge elemental profiles of statoliths and concentric increments showed high variability in Sr:Ca ratios both within and between individuals. The ratios suggested that many jellyfish had been exposed to a wide range of oceanographic regimes, while others had spent their whole lives in high Sr:Ca ratio waters. Elemental chemistry and concentric increments in the CaSO matrix of cubomedusan statoliths provide a tool to study cubozoan ecology. [ABSTRACT FROM AUTHOR]

Abstract: A new add-on package (LAICPMS) for the R language for statistical computing is presented, which greatly facilitates data reduction and visualisation (single tracks and 2D element maps) of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) data. The package determines many input parameters automatically and is easy to use. We present major and trace element distribution maps of natural calcite samples, processed using LAICPMS. Data processing from raw data to presented graphics takes only a few minutes. The empirical cumulative density function (ECDF) is used for optimised colour coding of the maps rather than linear or logarithmic scale, making a maximum of element-specific detail visible. For preprocessing, several different smoothing algorithms were evaluated and can be chosen by the user; for the presented data, a simple running median/running average was chosen. Typical data analysis is performed via short, easy-to-understand script files, and results can be used for further analyses within R. Owing to other R add-on packages utilised, the results can be output either numerically or as high-quality graphics in a wide range of file formats. Inheriting from its host environment R, the package is open-source software and freely available for all major computer platforms. [Copyright &y& Elsevier]

Abstract: Trace metal analysis of DGT gels using laser ablation inductively coupled plasma (LA-ICP-MS) has traditionally been carried out by ablating single spots along a line to provide high resolution data on trace metal distributions on a resin gel. This work compares the performance of two different LA-ICPMS systems, one at Lancaster University, UK and another at VUB, Belgium, in terms of instrument sensitivity and limit of detection in the analysis of trace metals (Co, Ni, Cu, Zn, Cd, and Pb) bound by a DGT resin gel using SPR-IDA resin. No defocusing of the laser beam was necessary to prevent burning through the resin gel and the internal standardization became very simple by using 13C, naturally present in the resin-gel, instead of impregnating a back-up layer with 115In. Furthermore, this work also explores the option of analysing the spatial distribution of resin bound trace metals by means of ablating a continuous line between two points and considers the advantages of using this approach. The work found that the LODs assessed on blank samples for Cu and Pb are similar for both LA-ICPMS systems, while for Co, Ni and Zn they are lower for the one at VUB and for Cd for the other one at Lancaster. The work found that the laser ablation systems at the two laboratories allowed more precise control over laser power and spot size than previously reported. For the line scan, the optimum scan parameters were determined as: scan speed of 50μms−1, output energy of 40% and repetition rate of 30Hz. An acquisition time of 25ms, resulted in a much lower resolution (10μm) compared to the spot ablation (a crater size of 100μm and also some space between craters) and a better sensitivity. The LODs using the line scan were found to be lower than those obtained by the spot ablation. However, for some of the metals the difference is rather small. This work suggests that the time and gas consumption achieved by using the line scan is about 30% lower than for the traditional spot scan. [Copyright &y& Elsevier]

Abstract: The Paraguay Belt in central South America is part of a larger chain of orogenic belts, including the Araguaia Belt to the northeast and potentially the Pampean Belt to the south, which are believed to mark the suture zone of the Clymene Ocean — interpreted amongst the youngest of the Gondwana amalgamation orogens. The post-orogenic São Vicente Granite crops out in the northern Paraguay Belt and cuts the basal unit of the deformed and metamorphosed Cuiabá Group. The age of this granite therefore provides a long sort after minimum age for orogenesis within the belt. Dating crystallisation of this important intrusion is challenging due to the presence of considerable common-Pb. However, based on LA-ICPMS dating of more than 100 zircons from three separate samples we interpret a robust crystallisation age for the São Vicente batholith at 518±4Ma. This age constrains the termination of deformation within the Paraguay Belt and the final accretion of the supercontinent Gondwana. [Copyright &y& Elsevier]

The compositions of fluid inclusions hosted in ore and gangue minerals from Mississippi Valley-type (MVT) Pb-Zn-Ba deposits of the Ozark Plateau region were measured to develop a regional hydro-geochemical conceptual model for ore emplacement. This model may explain the diverse compositions of fluids involved in mineral precipitation, the ore precipitation mechanism, and the temporal change in composition of fluids invading the ore districts. The conceptual model additionally provides evidence for what factors may have controlled deposit size, stratigraphic location, and Zn/Pb ratio. High Pb concentrations up to 1,000's of ppm were identified in sphalerite-hosted fluid inclusions from all of the region's districts. If these high Pb concentrations were transported in the same fluid with sulfide, then total sulfur concentration in the fluid must have been low. Mass balance calculations demonstrate that the Arkoma Basin, a presumed source basin for the mineralizing fluids, is too small to have contained enough fluid to precipitate the observed masses of sulfur in the larger MVT districts, given the low sulfide concentrations that could coexist in the fluid with such high concentrations of Pb. High methane concentrations in sphalerite-hosted fluid inclusions from all of the region's districts, in dolomite-hosted fluid inclusions from the Tri-State and Northern Arkansas districts, and quartz-hosted fluid inclusions from the Northern Arkansas district suggest that the prevailing redox conditions during MVT mineralization were reducing, making it unlikely that sulfate was transported in large concentrations in the fluids. During sphalerite precipitation, assuming saturation with respect to carbon dioxide, measured methane concentrations in sphalerite-hosted fluid inclusions would have required oxygen fugacity to have been at least two log units below the sulfate predominance field boundary. Fluid inclusion methane concentrations can also be used to estimate minimum burial depths of mineralization of about 0.08 to 1.2 km. Available evidence indicates that sulfide mineral precipitation in the Ozark Plateau MVT districts most likely occurred primarily as a result of the introduction of sulfide into a Pb- and Zn-rich ore fluid. In the two larger MVT districts, sulfide may have been supplied by local organic- and sulfur-rich carbonate facies. An apparent mixing line between high Ca/Na ratio and low Ca/Na ratio fluids hosted predominantly in main stage sulfide minerals and paragenetically late minerals, respectively, indicates the ore fluid was relatively Ca enriched. The lack of continuity in high Pb concentrations in fluid inclusions in sulfide and nonsulfide minerals from across the mineral parageneses suggests that the ore fluids entered the districts intermittently and/or had variable metal contents over time. [ABSTRACT FROM AUTHOR]

Abstract: This paper discusses new evidence of long-distance interaction networks in Island Southeast Asia obtained from geochemical analyses using SEM-EDXA and LA-ICPMS of 101 obsidian samples from 25 locations including seven obsidian sources and 19 archaeological sites. Given that there are obsidian sources distributed throughout much of Island Southeast Asia, the potential for obsidian studies to provide greater understanding of patterns of mobility and exchange in the Pre-Neolithic and Neolithic periods would seem to be considerable. This potential, however, remains largely unrealised as obsidian sourcing has hitherto only been carried out intermittently in Island Southeast Asia using PIXE-PIGME, XRF and other methods. [Copyright &y& Elsevier]

Abstract: Geochronological studies of samples from continuous crustal sections of fossil intra-oceanic arcs are paramount for determining the precise timing of major processes that took place during the building of an oceanic island-arc crust. In this study, laser ablation ICP-MS U–Pb zircon (and conventional Rb–Sr) analyses pinpoint the timing of major events responsible for crustal growth of the Kohistan paleo-island arc (Northern Pakistan). Inheritance in magmatic rocks is evidence for recycling of intra-arc material and indicates that the Kohistan arc may have formed as early as 135±4Ma. One older inherited grain indicates that the arc developed on a young oceanic lithosphere whose remnants include a c. 175Ma old component. An interesting consequence is that intra-oceanic arc magmas can yield inherited zircons, which can be much older than the arc system itself without requiring recycling back into the mantle by subduction processes. In the case of the Kohistan arc, ante-arc Neotethys oceanic lithosphere was tapped by arc magmas during their way upward into the arc crust. The oldest magmatic ages measured in this study fall in the range 101–102Ma (100.9±0.6 and 102.1±0.4Ma). This period corresponds to arc build-up and thickening of the arc crust. Leucogranitic melts dated at 89.9±0.4Ma and 90.9±1.0Ma are considered as produced by dehydration/melting reaction accompanying granulitisation of the thickened lower arc crust. A maximum age for this event is 97.7±0.7Ma, the age of emplacement of a garnet meta-tonalite affected by granulite facies metamorphism. Magmatic activity was still ongoing during and after the granulitisation as testified by emplacement of a diorite and a gabbro dated at 89.1±0.6 and 88.2±0.9Ma respectively. The upper part of the metaplutonic sequence contains diorite samples dated at 84.6±0.5Ma and 84.3±0.5Ma and as young as 81.1±0.7Ma. During this period, and based on the present day outcropping sequences, the mean crustal growth rate varied from 32 to 65km3/km/Ma (volume per unit width along the strike of the arc) which is comparable to the range for present day arcs of the Western Pacific region. The correspondence of crustal growth rates observed for present-day island arcs and the good preservation of the crustal section in the Kohistan arc, make this area an exceptional natural laboratory to study arc related processes and to check models of continental crust formation by arc accretion. [Copyright &y& Elsevier]

Abstract: The northern Madurai Block, southern India, lies directly south of, and partly deformed by, the Palghat–Cauvery Shear Zone System (PCSS) – a potential suture of the Neoproterozoic Mozambique Ocean. The Kadavur gabbro-anorthosite complex lies south of the PCSS, in the northern Madurai Block, and crystallized at 829±14Ma (LA-ICPMS zircon data) in a supra-subduction zone setting. The complex contains zircon ε Hf(t) values of −12.5 to −8.6 that represent Palaeoproterozoic T (DM) model ages (2.3–2.5Ga). These broadly agree with a whole rock neodymium T (DM) model age of 2287Ma. Oxygen isotope δ18O ratios range from 5.82‰ and 6.74‰. The parental magma for the gabbro-anorthosites are interpreted to be derived from a juvenile Neoproterozoic mantle contaminated by Mesoarchaean igneous infra-crustal sources. The gabbro-anorthosites intrude quartzites with dominantly Palaeoproterozoic detrital zircons that contain Neoarchaean and Mesoarchaean hafnium model ages. These quartzite zircons contain metamorphic rims that yield an age of 843±23Ma demonstrating the autochthonous nature of the gabbro-anorthosite complex. Later felsic magmatism is recorded by the 766±8Ma crystallisation age of the protolith of a felsic gneiss. Cryogenian magmatism in the Madurai Block is interpreted to form part of an extensive arc magmatic province within the southern East African Orogen that can be traced from central Madagascar, through southern India to the Wanni Complex of Sri Lanka. This province is interpreted to have formed above a south/west dipping subduction system as the Mozambique Ocean was subducted under the Neoproterozoic continent Azania. [Copyright &y& Elsevier]

Abstract: Zircon recrystallization is a common process during high-grade metamorphism and promotes partial or complete resetting of the original isotopic and chemical characteristics of the mineral and thus complicates U–Pb geochronological interpretation. In Central Brazil, this complexity may be illustrated by three composite mafic–ultramafic intrusions metamorphosed under amphibolite-to-granulite conditions. Their ages of emplacement and metamorphic ages have been a matter of controversy for the last thirty years. The Serra da Malacacheta and Barro Alto complexes make up the southernmost of these layered bodies and four samples from distinct rock types were investigated in order to verify the consequences of metamorphic alteration of zircon for U–Pb dating. Cathodoluminescent imaging reveals internal features which are typical of concomitant dissolution–reprecipitation processes, such as convolute zoning and inward-moving recrystallization fronts, even in samples in which partially preserved igneous textures are observed. Due to this extensive alteration, LA-ICPMS U–Pb isotopic analysis yielded inconclusive data. However, in situ Hf isotopic and trace-element analyses help to clarify the real meaning of the geochronological data. Low Lu/Hf (<0.004) and homogeneous 176Hf/177Hf t values imply that the zircon populations within individual samples have crystallized in a single episode, despite the observed variations in age values. Trace element signatures of zircon grains from garnet-bearing samples reveal that they were unreactive to the development of the peak metamorphism mineral assemblage and, thus, the main chemical feature in such grains is attributed to a coupled dissolution–reprecipitation process. However, in the Cafelândia amphibolite an additional alteration process is identified, probably related to the influx of late-stage fluids. Combined isotopic and geochemical investigation on zircon grains allowed the distinction of two magmatic events. The first corresponds to the crystallization of the Serra da Malacacheta Complex and characterizes a juvenile magmatism at ∼1.3Ga. The younger episode, recognized in the Barro Alto Complex, is dated at ca. 800Ma and is represented by mafic and ultramafic rocks showing intense contamination with continental crust, implying that the emplacement took place, most likely, in a continental back-arc setting. Altered zircon domains as well as titanite grains date the metamorphic event at ca. 760–750Ma. [Copyright &y& Elsevier]

We report new evidence from east Timor for the long-term prehistoric use of a single high-silicate obsidian source. Ten artefacts from Jerimalai shelter in east Timor analysed with SEM/EDXA and LA-ICPMS demonstrate the exploitation of this source began in the pleistocene by 42,000 calBP, and continued to be used periodically into the mid to late Holocene. The data supports previous results suggesting that a high-silicate obsidian of unknown location has been transported over considerable distance to rock shelter sites in the east of Timor. [ABSTRACT FROM AUTHOR]