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Cryogenic cave carbonates (CCC) are rare speleothems that form when water freezes inside cave ice bodies. CCC have been used as an proxy for permafrost degradation, permafrost thickness, or subsurface ice formation. The presence of these minerals is usually attributed to warm periods of permafrost degradation. We found coarse crystalline CCC types within transparent, massive congelation ice in two Pyrenean ice caves in the Monte Perido Massif: Devaux, located on the north face at 2828 m a.s.l., and Sarrios 6, located in the south face at 2780 m a.s.l. The external mean annual air temperature (MAAT) at Devaux is ~ 0°C, while at Sarrios 6 is ~ 2.5°C. In the Monte Perdido massif discontinuous permafrost is currently present between 2750 and 2900 m a.s.l. and is more frequent above 2900 m a.s.l. in northern faces. In Devaux, air and rock temperatures, as well as the presence of hoarfrost and the absence of drip sites indicate a frozen host rock. Moreover, a river flows along the main gallery, and during winters the water freezes at the spring causing backflooding in the cave. In contrast, Sarrios 6 has several drip sites, although the gallery where CCC were collected is hydrologically inactive. This gallery opened in recent years due to ice retreat. During spring, water is present in the gallery due to the overflow of ponds forming beneath drips. CCC commonly formed as sub-millimeter-size spherulites, rhombohedrons and rafts. 230Th ages of the same CCC morphotype indicate that their formation took place at 1953±7, 1959±14, 1957±14, 1958±15, 1974±16 CE in Devaux, while in Sarrios 6 they formed at 1964±5, 1992±2, 1996±1 CE. The cumulative probability density function indicates that the most probable formation occurred 1957-1965 and 1992-1997. The instrumental temperature record at 2860 m a.s.l. indicates positive MAAT in 1964 (0.2°C) and 1997 (0.8°C). CCC formation could thus correspond with those two anomalously warm years. The massive and transparent ice would indicate a sudden ingress of water and subsequent slow freezing inside both caves during those years. Probably, CCC formation took place at a seasonal scale during the annual cycle.

Petrographic features, mineralogy, and stable isotopes from two stalagmites, ANJB-2 and MAJ-5, respectively from Anjohibe and Anjokipoty caves, allow distinction of three intervals of the Holocene in NW Madagascar. The Malagasy early Holocene (between ca. 9.8 and 7.8 ka) and late Holocene (after ca. 1.6 ka) intervals (MEHI and MLHI, respectively) record evidence of stalagmite deposition. The Malagasy middle Holocene interval (MMHI, between ca. 7.8 and 1.6 ka) is marked by a depositional hiatus of ca. 6500 years. Deposition of these stalagmites indicates that the two caves were sufficiently supplied with water to allow stalagmite formation. This suggests that the MEHI and MLHI intervals may have been comparatively wet in NW Madagascar. In contrast, the long-term depositional hiatus during the MMHI implies it was relatively drier than the MEHI and the MLHI. The alternating wet–dry–wet conditions during the Holocene may have been linked to the long-term migrations of the Intertropical Convergence Zone (ITCZ). When the ITCZ's mean position is farther south, NW Madagascar experiences wetter conditions, such as during the MEHI and MLHI, and when it moves north, NW Madagascar climate becomes drier, such as during the MMHI. A similar wet–dry–wet succession during the Holocene has been reported in neighboring locations, such as southeastern Africa. Beyond these three subdivisions, the records also suggest wet conditions around the cold 8.2 ka event, suggesting a causal relationship. However, additional Southern Hemisphere high-resolution data will be needed to confirm this.

We present two isotopic (δ18O and δ13C) sequences of a twin-stalagmite from Zhuliuping Cave, southwestern China, with 230Th dates from 14.6 to 4.6 ka. The stalagmite δ18O record characterizes orbital- to decadal-scale variability of Asian summer monsoon (ASM) intensity, with the Holocene optimum period (HOP) between 9.8 and 6.8 ka BP which is reinforced by its co-varying δ13C data. The large multi-decadal scale amplitude of the cave δ18O indicates its high sensitivity to climate change. Four centennial-scale weak ASM events during the early Holocene are centered at 11.2, 10.8, 9.1 and 8.2 ka. They can be correlated to cold periods in the northern high latitudes, possibly resulting from rapid dynamics of atmospheric circulation associated with North Atlantic cooling. The 8.2 ka event has an amplitude more than two-thirds that of the Younger Dryas (YD), and is significantly stronger than other cave records in the Asia monsoon region, likely indicating a more severe dry climate condition at the cave site. At the end of the YD event, the δ13C record lags the δ18O record by 300–500 yr, suggesting a multi-centennial slow response of vegetation and soil processes to monsoon enhancement.

Coarse crystalline cryogenic cave carbonates (CCCcoarse) dated to the last glacial period are common in central European caves and provide convincing evidence of palaeo-permafrost during this time. Little is known, however, about the exact nature of the environment in which CCCcoarse formed as no modern analogue setting is known. Here, we report the first findings of sub-recent, albeit inactive, CCCcoarse from a cave of the Western Alps which is located in the present-day permafrost zone. The globular shape and the presence of ubiquitous euhedral crystal terminations are comparable to previously described aggregates from the last glacial period and strongly suggest that these aggregates formed subaqueously in pools lacking agitation. Furthermore, stable isotope values of mm-sized spheroids point to calcite precipitation in a closed system with respect to CO2 strongly supporting the hypothesis of a cryogenic origin associated with the freezing of water ponds. U-series analyses revealed three clusters of late Holocene calcite precipitation intervals between 2129 and 751 a b2k. These ages correlate with known periods of elevated summer temperatures, suggesting that warming and thawing of the permafrozen catchment above the cave allowed water infiltration into the karst system. The growth of CCCcoarse resulted from the re-freezing of this water in the still cold karst cavities.

A global array of proxy records suggests that the 4.2 ka event marks an ~ 300-year period of major climate anomaly. However, the climatic manifestation of this event, including its onset, duration, and termination, remain less clear in the Indian summer monsoon (ISM) domain. Here, we present a new speleothem oxygen isotope (δ 18 O) record from Mawmluh Cave, Northeast India, which provides an annually-resolved record of changes in ISM strength between ~ 4.440 and 3.780 ka BP. Our δ 18 O record is constrained by 18 230 Th dates with an average age uncertainty of p13 years and a dating resolution of ~ 40 years, which allow us to characterize the timing and structure of the 4.2 ka event with an unprecedented detail. The overall expression of the 4.2 ka event in our record shares broad similarities with a previous δ 18 O record from the Mawmluh Cave as well as with other previous lower-resolution proxy reconstructions of the ISM. However, unlike some previous ISM records, where the 4.2 ka event has been described as a singular multi-centennial period of anomalously weak ISM, our data suggest a more variable response of ISM during this period. The 4.2 ka event in our record exhibits a three-stage structure, characterized by highly variable ISM between ~ 4.255 and 4.070 ka BP and a distinct pluvial phase from ~ 4.070–4.010 ka BP. The latter abruptly ( 10 years) culminated into a relatively weaker phase of ISM, which was punctuated by a number of multidecadal periods of anomalously drier conditions. While, our record shows evidence of a discernible beginning for the 4.2 ka event, there is no clear evidence of its end in thus, suggesting that the ISM experienced a major regime-shift or transition at ~ 4.0 ka BP.

The Levant constitutes an important region for assessing linkages between climate and societal changes throughout the course of human history. However, large uncertainties remain in our understanding of the region's hydroclimate variability under varying boundary conditions. Here we present a new high-resolution, precisely dated speleothem oxygen-carbon isotope and Sr/Ca records, spanning the last 20 ka from Jeita Cave, northern Levant. Our record reveals a higher (lower) precipitation-evaporation (P-E) balance during the Last Glacial Maximum and Bolling interstadial (Heinrich stadial 1). The early-middle Holocene is characterized by a trend toward higher P-E state, culminating between similar to 7 and 6 ka. The middle-late Holocene is characterized by two millennial-length drier periods during 5.3-4.2 and 2.8-1.4 ka. On submillennial time scale, the northern Levant climate variability is dominated by 500 year periodicity. Comparisons with the regional proxy records suggest persistent out-of-phase climate variability between the northern and southern Levant on a wide range of timescales.

Earthquakes hit urban centres in Europe infrequently, but occasionally with disastrous effects. Obtaining an unbiased view of seismic hazard (and risk) is therefore very important. In principle, the best way to test probabilistic seismic hazard assessments (PSHAs) is to compare them with observations that are entirely independent of the procedure used to produce PSHA models. Arguably, the most valuable information in this context should be information on long-term hazard, namely maximum intensities (or magnitudes) occurring over time intervals that are at least as long as a seismic cycle. The new observations can provide information of maximum intensity (or magnitude) for long timescale as an input data for PSHA studies as well. Long-term information can be gained from intact stalagmites in natural caves. These formations survived all earthquakes that have occurred over thousands of years, depending on the age of the stalagmite. Their 'survival' requires that the horizontal ground acceleration (HGA) has never exceeded a certain critical value within that time period. Here, we present such a stalagmite-based case study from the Little Carpathians of Slovakia. A specially shaped, intact and vulnerable stalagmite in the Plavecka priepast cave was examined in 2013. This stalagmite is suitable for estimating the upper limit of horizontal peak ground acceleration generated by prehistoric earthquakes. The critical HGA values as a function of time going back into the past determined from the stalagmite that we investigated are presented. For example, at the time of Joko event (1906), the critical HGA value cannot have been higher than 1 and 1.3 m/s(2) at the time of the assumed Carnuntum event (similar to 340 AD), and 3000 years ago, it must have been lower than 1.7 m/s(2). We claimed that the effect of Joko earthquake (1906) on the location of the Plavecka priepast cave is consistent with the critical HGA value provided by the stalagmite we investigated. The approach used in this study yields significant new constraints on the seismic hazard, as tectonic structures close to Plavecka priepast cave did not generate strong earthquakes in the last few thousand years. The results of this study are highly relevant given that the two capitals, Vienna and Bratislava, are located within 40 and 70 km of the cave, respectively. Web of Science 21 5 1130 1111

Middle Holocene cultures have been widely studied around the Eastern-Mediterranean basin in the last 30 years and past cultural activities have been commonly linked with regional climate changes. However, in many cases such linkage is equivocal, in part due to existing climatic evidence that has been derived from areas outside the distribution of ancient settlements, leading to uncertainty from complex spatial heterogeneity in both climate and demography. A few high-resolution well-dated paleoclimate records were recently established using speleothems in the Central and Eastern-Mediterranean basin, however, the scarcity of such records in the western part of the Mediterranean prevents us from correlating past climate evolutions across the basin and deciphering climate–culture relation at fine timescales. Here we report the first decadal-resolved Mid-Holocene climate proxy records from the Western-Mediterranean basin based on the stable carbon and oxygen isotopes analyses of two U/Th dated stalagmites from the Gueldaman GLD1 Cave in Northern Algeria. Comparison of our records with those from Italy and Israel reveals synchronous (multi) centennial dry phases centered at ca. 5600, ca. 5200 and ca. 4200 yr BP across the Mediterranean basin. New calibrated radiocarbon dating constrains reasonably well the age of rich anthropogenic deposits (e.g., faunal remains, pottery, charcoal) excavated inside the cave, which allows the comparison between in situ evidence of human occupation and of climate change. This approach shows that the timing of a prolonged drought at ca. 4400–3800 yr BP blankets the onset of cave abandonment shortly after ca. 4403 cal yr BP, supporting the hypothesis that a climate anomaly may have played a role in this cultural disruption.

δ 18 O in speleothems is a powerful proxy for reconstruction of precipitation patterns in tropical and sub-tropical regions. The aim of this study is to calibrate the δ 18 O record of speleothems against historical precipitation and river discharge data in central Brazil, a region directly influenced by the Southern Atlantic Convergence Zone (SACZ), a major feature of the South American Monsoon System (SAMS). The present work is based on a sub-annual resolution speleothem record covering the last 141 years (the period between the years 1870 and 2011) from a cave in central Brazil. The comparison of this record with instrumental hydroclimate records since 1921 allows defining a strong relationship between precipitation variability and stable oxygen isotope ratios from speleothems. The results from a monitoring program of climatic parameters and isotopic composition of rainfall and cave seepage waters performed in the same cave, show that the rain δ 18 O variability is dominated by the amount effect in this region, while δ 18 O drip water remains almost constant over the monitored period (1.5 years). The δ 18 O of modern calcite, on the other hand, shows clear seasonal variations, with more negative values observed during the rainy season, which implies that other factors also influence the isotopic composition of carbonate. However, the relationship between δ 18 O of carbonate deposits and rainwater is supported by the results from the comparison between speleothem δ 18 O records and historical hydroclimate records. A significant correlation between speleothem δ 18 O and monsoon rainfall variability is observed on sub-decadal time scales, especially for the monsoon period (DJFM and NDJFM), once the rainfall record have been smoothed with a 7–9 years running mean. This study confirms that speleothem δ 18 O is directly associated with monsoon rainfall variability in central Brazil. The relationship between speleothem δ 18 O records and hydroclimatic historical records allows approximation of the absolute changes in mean annual rainfall during the last millennia in the SACZ/SAMS domain.

We present the updated Holocene section of the Sofular Cave record from the southern Black Sea coast (northern Turkey); an area with considerably different present-day climate compared to that of the neighboring Eastern Mediterranean region. Stalagmite δ 13 C, growth rates and initial ( 234 U/ 238 U) ratios provide information about hydrological changes above the cave; and prove to be more useful than δ 18 O for deciphering Holocene climatic variations. Between ∼9.6 and 5.4 ka BP (despite a pause from ∼8.4 to 7.8 ka BP), the Sofular record indicates a remarkable increase in rainfall amount and intensity, in line with other paleoclimate studies in the Eastern Mediterranean. During that period, enhanced summertime insolation either produced much stronger storms in the following fall and winter through high sea surface temperatures, or it invoked a regional summer monsoon circulation and rainfall. We suggest that one or both of these climatic mechanisms led to a coupling of the Black Sea and the Mediterranean rainfall regimes at that time, which can explain the observed proxy signals. However, there are discrepancies among the Eastern Mediterranean records in terms of the timing of this wet period; implying that changes were probably not always occurring through the same mechanism. Nevertheless, the Sofular Cave record does provide hints and bring about new questions about the connection between regional and large scale climates, highlighting the need for a more extensive network of high quality paleoclimate records to better understand Holocene climate.

The suitability of in situ Secondary Ionisation Mass Spectrometry (SIMS) techniques for measuring O isotopes in speleothems is critically examined by applying this technique to a 500-year interval of the well-known Hulu Cave record (Wang, Y.J., Cheng, H, Edwards, R.L., An, Z.S., Wu, J.Y., Shen, C.C., Dorale, J.A., 2001. A high-resolution absolute dated late Pleistocene monsoon record from Hulu Cave, China. Science, 294: 2345–2348). This interval includes a large abrupt + 2‰ shift in δ18O at 16.07 ka, which may correlate to Heinrich Event I (H1). The high-resolution SIMS method provides annual to near-annual δ18O data, thereby increasing the temporal resolution of the previously published Hulu Cave isotopic data by approximately tenfold. SIMS δ18O data reveal that 75% of the abrupt isotopic shift at 16.07 ka occurred in just 1 to 2 years and the full + 2‰ occurs over 6 years, compared with an upper limit of 20 years as previously determined by conventional methods employing micro-cutting, acid-digestion and CO2-gas source mass spectrometry methods. SIMS δ18O data also reveal numerous high amplitude (1–3‰), high frequency (

An absolute-dated stalagmite from Kaite Cave (Ojo Guareña Karst Complex, N Spain) provides a nearly continuous, high-resolution record of a proxy of regional precipitation patterns through the 4.9–0.9 ka BP interval. This record is based on the Mg/Ca ratio of the calcite and its variation through the stalagmite stratigraphy, which is interpreted to be primarily driven by changes in precipitation amount. The calibration of the proxy is supported by the present-day monitoring carried out in the cave for the last 10 years, which reveals a robust inverse relationship between the inter-annual/inter-decadal variability of rainfall and the Mg concentration of dripwaters and precipitating speleothems. The record of paleoprecipitation, based on 2400 Mg/Ca measurements, shows strong variability at inter-annual to inter-decadal scales, and more subtle but significant changes at secular to millennial scales. This long-term paleohydrological evolution outlines five successive intervals with consistent trends, which are bounded by abrupt shifts in the regional precipitation. These shifts took place at 4.65, 4.2, 2.6, and 1.3 ka BP. Significantly, the intervals of maximum precipitation of the whole record (around 4.9–4.65, 2.6–2.45, and 1.3–1.1 ka BP) can be related with episodes of minimum solar activity and correlated with cold climatic events elsewhere., Contribution to research projects 28 CGL2010-21499-BTE and CGL2013-43257-R of the Spanish R+D National Program 29 (MINECO) and research groups ‘‘Paleoclimatology and Global Change’’ and ‘‘Laser Induced 30 Breakdown Spectroscopy (LIBS)’’ from the UCM (Spain).

The Seso Cave System (SCS, South Central Pyrenees, Northeastern Spain) develops in poorly soluble marly interstratum between limestone beds of Eocene age. We propose an innovative and singular pseudokarstic speleogenetic model under vadose conditions based on cave morphological evidence, physicochemical and mineralogical characteristics of the Eocene marly host rock, U-Th dating of cave deposits, and local geological and geomorphological information. Eocene marls are shown to be sensitive to dispersion processes supported by their high clay content and the high concentration of sodium and low electrical conductivity in the seepage water. Runoff inside the cave results from water that infiltrates through joints and seepage water in cave walls. Thereby piping processes become very active, triggering mechanical scouring and outwashing mechanisms. The hydraulic gradient required to develop piping activity is determined by regional fluvial incision. The base level controlling water discharge during opening of the SCS coincides with a terrace of the Ara River dated at 65. ka. BP. Considering this age, as well as the U-Th age of the oldest speleothems dated in the cave at 38. ka. BP, the timing of the SCS interstratal piping-cave speleogenesis is constrained to the Upper Pleistocene; very likely at the end of Marine Isotope Stage 4 during a period characterized by high water availability following glacial retreat in northern Iberian mountains. © 2014 Elsevier B.V., This research was funded by CGL2009-10455/BTE and CGL2010-16376 (HIDROPAST) projects of the Spanish Government (Ministerio de Ciencia e Inovación) and the European Regional Development Fund (FEDER) and a Sobrarbe Geopark research grant. It is a contribution of the PaleoQ Group (Aragón Regional Government). We thank Julie Retrum and Yanbin Lu (University of Minnesota) and Enrique Oliver (Universidad de Zaragoza) for the help in the laboratory work and Jaume Mas and Xavier Fuertes (Grupd'Espeleologia de Badalona) for field cave mapping support and Josu Aranbarri for Fig. 1 design.We appreciate very much the comments by Prof. Jo De Waele, an anonymous reviewer and Prof. Andrew J. Plater (Editor), which have improved the final version of the manuscript.

Seven U-Th dates, 560 δ 18 O data and microscopic sequences were measured for stalagmites from two high-altitude caves in Shennongjia area, Hubei Province. Variations of the decadal-resolution stalagmite δ 18 O record from Swan Cave (1600 m elevation) reflect large spatial changes in circulation strength and precipitation of Asian monsoon. The evidence comes from a great similarity among the stalagmite δ 18 O records from Nanjing, Jiangsu Province; Libo, Guizhou Province and here studied area during the last deglaciation, including a part interval of Younger-Dryas event and Bolling-Allerod. A 30-year-resolution stalagmite δ 18 O record from Yongxing Cave (1400 m elevation), 70 km away from Swan Cave, reveals a rapid transition of Asian monsoon climate during Termination 3 at about 245±5 kaBP. Based on 3 U-Th dates and about 5000 continuous annual bands, a millennial dry episode has been observed during Asian monsoonal Termination 3 from the Yongxing δ 18 O profile. With respect to its structure, duration and transition, the dry reversal, as indicated by our stalagmite δ 18 O record, generally agrees with the pattern of the YD event well-expressed in the Chinese stalagmite δ 18 O records. This YD-type event is characterized by a large decrease in δ 18 O value as much as 2.30‰, more than half of the δ 18 O excursion between glacial/interglacial periods, and lasts 1371±59 a determined by the annual counting chronology. After this event, the monsoon climate shifted abruptly into the interglacial period within 74±4 a. Our data corroborate the view that the repeated occurrence of YD-type event was not an “accident”, possibly resulted from the coupling of ice-sheet and oceanic/atmospheric circulations.

A stalagmite that grew during the Holocene (between 4.9 and 0.9 ka BP) in Kaite Cave (Ojo Guarena Karst Complex, Burgos, N Spain) has been analyzed by Laser-Induced Breakdown Spectroscopy (LIBS) with the aim of reconstructing secular variations in the hydrochemistry of the karst system, in turn related to changes in the environment outside the cave. LIBS analyses yield significant changes in Mg/Ca and Sr/Ca intensity ratios through the stalagmite, which reveal consistent trends and patterns at decadal to centennial scales. The origin of the observed changes in Mg/Ca and Sr/Ca ratios is discussed in the framework of the cave system and the regional climatic variability, particularly the changes in precipitation.

A 50 kyr-long exceptionally well-dated and highly resolved stalagmite oxygen (δ 18O) and carbon (δ 13C) isotope record from Sofular Cave in northwestern Turkey helps to further improve the dating of Greenland Interstadials (GI) 1, and 3–12. Timing of most GI in the Sofular record is consistent within ±10 to 300 years with the “iconic” Hulu Cave record. Larger divergences (>500 years) between Sofular and Hulu are only observed for GI 4 and 7. The Sofular record differs from the most recent NGRIP chronology by up to several centuries, whereas age offsets do not increase systematically with depth. The Sofular record also reveals a rapid and sensitive climate and ecosystem response in the eastern Mediterranean to GI, whereas a phase lag of ∼100 years between climate and full ecosystem response is evident. Finally, results of spectral analyses of the Sofular isotope records do not support a 1,470-year pacing of GI.

[1] A U-Th dated 90,000 year-long speleothem oxygen isotope record from southern Brazil anti-correlates remarkably with the cave calcite records from eastern China, but positively correlates with the speleothem record from northeastern Brazil, suggesting an interhemispheric anti-phasing of rainfall on both millennial and orbital timescales, likely related to displacement in the mean position of the intertropical convergence zone and associated asymmetry in Hadley circulation. The phase relationships among these records are consistent with the hypothesis that abrupt climate events during the last glacial period are triggered by oceanic circulation changes in the high latitudes and enhanced by tropical feedbacks.

Marine deposits at +20 ± 3 m on the tectonically stable coastlines of Bermuda and the Bahamas support the hypothesis of a partial collapse of the Antarctic ice sheet during the middle Pleistocene. Beach sediments fill a sea cave at +22 m in Bermuda, and horizontal, fenestrae-filled beds crop out on platforms at two sites as high as +21 m in Eleuthera, Bahamas. Carbonate beach sands are bound by an early generation of isopachous fibrous cement that is characteristic of a phreatic marine environment. Amino acid racemization and TIMS (thermal-ionization mass spectrometry) dates constrain the age of the deposits to between 390 and 550 ka, while proxy evidence supports a correlation with oxygen isotope stage 11. This direct geologic evidence of a 20% decrease in polar ice during the middle Pleistocene has important implications for the stability of ice sheets during warm interglaciations.