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The cave of Saint-Marcel is known for its extensive network (64 km of galleries) and its history of human occupation (Middle Palaeolithic and Neolithic) in the entrance area. Close observation of the main network reveals areas with high concentrations of broken speleothems, which are usually attributed to the first tourist visits of the nineteenth century. However, archaeo-geomorphological mapping of the broken speleothems, many of which are lying on the floor and sealed by stalagmite regrowth or crust, indicates intentional organisation of the underground space into speleothem supply zones and zones in which the speleothems were used to build structures. Age estimates of the stalagmite seals on these human-made structures suggest that the structures were a result of human activity that occurred between the end of the Upper Palaeolithic and the European Mesolithic. These age estimates radically change the way we look at the broken speleothems in the cave of Saint-Marcel and the structures associated with them. They bring to light the engagement of past human communities with the deep underground environment, at more than 1.5 km from the cave entrance, which can only be accessed by crossing obstacles (pits) that, today, are considered as difficult to be crossed. Our findings and ongoing research stress the unequivocal archaeological significance of the cave. [ABSTRACT FROM AUTHOR]

A revaluation of the relative sea-level (RSL) indicators in the Baia di Infreschi (Cilento, Southern Italy) supported by new 30 U/Th dating on speleothems indicates that the upper level of Lithophaga burrows identified by Bini et al. (2020) at ∼9 m a.s.l. and correlated to the Last Interglacial (LIG) highstand should be referred to the highstand of the MIS 9e, whereas the local RSL for the highstand of the LIG is now reassessed at 5.3 ± 0.18 m a.s.l. The upper level of the Lithophaga marker can be followed for ∼12 km along the coast, suggesting a substantial absence of important relative tectonic movements. In the Baia di Infreschi an additional marine indicator, a notch sealed by a flowstone dated ∼110 ka, indicates several phases of RSL stationing below the maximum highstand of the LIG. The presence of flowstones as low as 2 m a.s.l. dated to the MIS 7 shows that the highstand of MIS 7 was probably below the present sea level. All these evidences allow us to reassess the stratigraphy of some archaeological caves in the area, indicating that the sedimentary successions preserved there are older than what was previously believed.

Sedimentological and chronological analyses of coastal dunes can determine their sedimentation processes and yield information that can reflect changes in local marine environments (e.g., information on climate, biology, and sea‐level changes in tectonically stable areas). In this study, Late Quaternary deposits on Shidao Island, one of the Xisha Islands, South China Sea, were analysed using techniques such as U/Th dating to obtain the following results: (1) Four lithofacies associations and two unconformities were identified from the deposits on Shidao Island. On this basis, the Shidao Island sediments can be divided into three stages of aeolian sediments and one stage of beach rock sediments. (2) U/Th dating revealed that the aeolian deposits on Shidao Island formed during three periods, namely, marine isotope stages 5.2, 5.1, and 4, and that the beachrocks were formed in the Holocene when the sea level rose to its present height. (3) The aeolianites on Shidao Island all formed in an environment in which the sea level was relatively stable or slowly falling. This study determined for the first time the specific sedimentary ages of the aeolianites on Shidao Island, and reconstructed the sedimentation process of the deposits on Shidao Island based on palaeo‐sea‐level changes. These results can provide more reliable geochronology data for the future study of Late Quaternary marine environments across the East Asian region. [ABSTRACT FROM AUTHOR]

Abstract The Erdmannshöhle is located at the NE margin of the Dinkelberg plateau in SW Germany. With a length of 2315 m, it is the longest cave in the deep open karst area near the village of Hasel. Three main cave levels developed in moderately SW-dipping, thinly bedded and fractured limestones of the Upper Muschelkalk (Triassic). The youngest cave level containing the cave stream is still active. Eighteen samples for U/Th dating were taken from the oldest and the intermediate cave levels. At the oldest cave level, the ages range from 162 to 110 ka, indicating speleothem growth starting in the middle Beringen Glaciation and terminating at the end of the Eem Interglacial. At the intermediate cave level, the ages range from 100 to 12 ka, i.e. early Birrfeld Glaciation to Younger Dryas Stadial. The age dating shows that speleothem growth did not cease completely during long periods of harsh climate conditions during the Beringen and Birrfeld glaciations and that permafrost terminating speleogenesis and speleothem growth was thus probably established only temporarily over relatively short periods. A conceptual model for the Middle Pleistocene to Holocene development of the Erdmannshöhle is presented within the framework of modern Quaternary lithostratigraphy. This model facilitates a first correlation of the cave evolution with the Middle to Late Pleistocene depositional record in the Möhlinerfeld, which is a key area for modern Quaternary lithostratigraphy in Switzerland and Southern Germany. Thus, speleological and Quaternary research, both based on a regional scale data compilation, complement one another with respect to the timing of events and the landscape evolution during the Quaternary and Late Neogene.

Relative sea‐level (RSL) evolution during Marine Isotopic Stage (MIS) 5 in the Mediterranean basin is still not fully understood despite a plethora of morphological, stratigraphic and geochronological studies carried out on highstand deposits of this area. In this review we assembled a database of 323 U/Th‐dated samples (e.g. corals, molluscs, speleothems) which were used to chronologically constrain RSL evolution within MIS 5. The application of strict geochemical criteria to the U/Th samples indicates that only ~33% of data available for the Mediterranean Sea can be considered 'reliable'. Most of these data (~65%) refer to the MIS 5e highstand, while only ~17% could be related to the MIS 5a. No attribution to MIS 5c can be unequivocally supported. Nevertheless, the resulting framework does not allow us to define a satisfactory RSL trend during the MIS 5e highstand and subsequent MIS 5 substages. Overall, the proposed selection of reliable/unreliable data would be useful for detecting areas where MIS 5 substage attributions are not supported by confident U/Th chronological data and thus the related reconstructions need to be revised. In this regard, the resulting framework calls for a reappraisal and re‐examination of the Mediterranean records with advanced geochronological methodologies. [ABSTRACT FROM AUTHOR]

We present three unreported U/Th dates on coral abraders recovered from Lapita occupations at the 'Otea and Vuna sites, in Vava'u, Kingdom of Tonga. Integrated with existing radiocarbon and U/Th dates for Vava'u, we also provide a single‐phase Bayesian model for Lapita chronology in these islands. [ABSTRACT FROM AUTHOR]

A buried travertine deposit, identified in a well at Prima Porta (to the north west of Rome, Italy), was investigated using a multidisciplinary approach that included stable isotope geochemistry, mineralogy, petrography and radiometric dating. The travertine body is located just along the western boundary of the Tiber valley, a morpho-tectonic depression of extensional origin; it is associated with the rise of a deep-seated, hypothermal, saline, CO 2 -rich fluid. The depositional environment was inferred by the macroscopic features of core and microfacies analysis, which suggested that travertine deposition was associated with a low to moderate energy environment, such as gently-dipping, shallow pools on low-angle, terraced slopes. A hydrothermal system, characterised by long circulation paths at depth, and deeply derived CO 2 -dominated fluids, are supported by geochemical analyses. According to radiometric dating, travertine deposition occurred from between 53.5 ± 10 ka to 24.2 ± 4.7 ka; the activation of the travertine-depositing spring was probably coeval with the wettest climatic conditions occurring during MIS3, whereas the end of deposition coincides with the cold and arid phase of the last glacial maximum. [ABSTRACT FROM AUTHOR]

A detailed geomorphological study was performed in the Atxurra‐Armiña cave system (northern Iberian Peninsula) to decode landscape evolution, palaeoenvironmental changes and human use of a cave within an Inner Archaeological Context. The results show an average incision rate of the river of <0.083 mm a–1 for at least the last 419 ka, with interruptions due to sedimentary inputs. Moreover, allostratigraphic units comprising fluviokarstic deposits at the base and flowstone formation at the top have been shown to be climatically controlled, formed either during glacial–interglacial cycles or during interstadial cycles. Finally, when the cave was used by humans in the Late Magdalenian, the lower entrance was closed, and they must therefore have entered the cave through the upper entrance. To reach the sectors selected to decorate the panels, they probably travelled from the upper cave level, as the current crawlway was wider than today, according to our U/Th dating. Once these visitors reached the panels, the floor in the main gallery would have been around 15 cm lower than at present. However, the morphology of the conduit was similar; this has significant implications for understanding and interpreting the human use of the cave during the Palaeolithic. [ABSTRACT FROM AUTHOR]

Quantifying rates of river incision and continental uplift over Quaternary timescales offer the potential for modelling landscape change due to tectonic and climatic forcing. In many areas, river terraces form datable archives that help constrain the timing and rate of valley incision. However, old river terraces, with high‐level deposits, are prone to weathering and often lack datable material. Where valleys are incised through karst areas, caves and sediments can be used to reconstruct the landscape evolution because they can record the elevation of palaeo‐water tables and contain preserved datable material. In Normandy (N. France), the Seine River is entrenched into an extensive karstic chalk plateau. Previous estimates of valley incision were hampered by the lack of preserved datable fluvial terraces. A stack of abandoned phreatic cave passages preserved in the sides of the Seine valley can be used to reconstruct the landscape evolution of the region. Combining geomorphological observations, palaeomagnetic and U/Th dating of speleothem and sediments in eight caves along the Lower Seine valley, we have constructed a new age model for cave development and valley incision. Six identified cave levels up to ∼100 m a.s.l. were formed during the last ~1 Ma, coeval with the incision of the Seine River. Passage morphologies indicate that the caves formed in a shallow phreatic/epiphreatic setting, modified by sediment influxes. The valley's maximum age is constrained by the occurrence of late Pliocene marine sand. Palaeomagnetic dating of cave infills indicates that the highest‐level caves were being infilled prior to 1.1 Ma. The evidence from the studied caves, complemented by fluvial terrace sequences, indicates that rapid river incision occurred during marine isotope stage (MIS) 28 to 20 (0.8–1 Ma), with maximal rates of ~0.30 m ka−1, dropping to ~0.08 m ka−1 between MIS 20–11 (0.8–0.4 Ma) and 0.05 m ka−1 from MIS 5 to the present time. © 2020 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The Erdmannshöhle is located at the NE margin of the Dinkelberg plateau in SW Germany. With a length of 2315 m, it is the longest cave in the deep open karst area near the village of Hasel. Three main cave levels developed in moderately SW-dipping, thinly bedded and fractured limestones of the Upper Muschelkalk (Triassic). The youngest cave level containing the cave stream is still active. Eighteen samples for U/Th dating were taken from the oldest and the intermediate cave levels. At the oldest cave level, the ages range from 162 to 110 ka, indicating speleothem growth starting in the middle Beringen Glaciation and terminating at the end of the Eem Interglacial. At the intermediate cave level, the ages range from 100 to 12 ka, i.e. early Birrfeld Glaciation to Younger Dryas Stadial. The age dating shows that speleothem growth did not cease completely during long periods of harsh climate conditions during the Beringen and Birrfeld glaciations and that permafrost terminating speleogenesis and speleothem growth was thus probably established only temporarily over relatively short periods. A conceptual model for the Middle Pleistocene to Holocene development of the Erdmannshöhle is presented within the framework of modern Quaternary lithostratigraphy. This model facilitates a first correlation of the cave evolution with the Middle to Late Pleistocene depositional record in the Möhlinerfeld, which is a key area for modern Quaternary lithostratigraphy in Switzerland and Southern Germany. Thus, speleological and Quaternary research, both based on a regional scale data compilation, complement one another with respect to the timing of events and the landscape evolution during the Quaternary and Late Neogene. [ABSTRACT FROM AUTHOR]

• South China Sea Holocene large fluctuating marine reservoir ages >than 300 14C yr. • ΔR at South China Sea was controlled by Peruvian upwelling and East Asian Monsoon. • Abrupt shifts at 5.5 ka were similar to those from tropical East Pacific and GBR. Here, we report new estimates of local marine radiocarbon reservoir ages from northwestern Luzon Island in the Philippines, on the east side of the South China Sea. Data for two periods, through the 1940's and the mid-Holocene, were derived from modern and fossil corals. Our results from Luzon Island show variable ΔR values, from −39 ± 25 to 337 ± 27 14C yr over the past 6000 years and highlight the importance of understanding temporal ΔR changes to obtain accurate radiocarbon dates for mid-Holocene samples. An abrupt shift in ΔR at ∼5.5 ka BP, in the east side of the South China Sea, can be attributed to changes in the intensity of the upwelling, in the eastern Pacific, and to the East Asian Monsoon. Additional reservoir age data from the Pacific is likely to reveal details of oceanographic and climate changes at this time. [ABSTRACT FROM AUTHOR]

• Radiometric ages of CWC of the Adriatic Sea shows different colonization periods. • The first occurrence of CWC in the southern Adriatic Sea is dated to the LGM. • The lack of CWC during the S1 documents oxygen deficiency at intermediate depths. • The NAdDW trajectory along the W Adriatic Sea controls the asymmetrical CWC settling. The deep southern Adriatic Sea is home of widespread cold-water coral colonization (Madrepora oculata , Lophelia pertusa , Desmophyllum dianthus) which is at present limited by large to its western (Apulian) margin and central part, including the Bari Canyon system. On the contrary, the eastern side is today almost deprived of significant coral growth and this asymmetrical distribution has been ascribed primarily to the action of the North Adriatic Dense Water (NAdDW) that impinges more efficiently on the Apulian margin. The collection of subfossil specimens of M. oculata , L. pertusa and D. dianthus provided the very first dates for cold-water coral colonization along the eastern margin. Once combined with known distribution of live cold-water corals and fossil occurrences in the southern Adriatic Sea, uranium-series dating provides evidence of (i) coral presence in the southeastern Adriatic during the Last Glacial Maximum (LGM), followed by (ii) a time of basin-wide colonization after the post-Last Glacial Maximum and encompassing the Younger Dryas, (iii) another time of undocumented coral presence with the onset of Sapropel S1. Perturbations of the thermohaline circulation in this sector of the Mediterranean basin might have governed the presence and demise of the resident cold-water coral populations interfering with strength and trajectories of main water masses. It is hypothesized that the achievement of the current asymmetrical distribution did occur since the end of S1 protracting to present time. The post-S1 reorganization likely brought to the current hydrological situation where the influence of NAdDW prevails in the western side and corals are doing at best on its trajectory. The scarcity of datable material makes the proposed scenario open to debate and in need of further supporting evidence. [ABSTRACT FROM AUTHOR]

In environmental age dating the 230Th/232Th activity ratio is widely used as an indicator of detrital contamination. A clear relationship between this activity ratio and the carbonate sample's age has previously been demonstrated, whereby a detrital correction must be applied when the 230Th/232Th activity ratio of the leach drops to 20. We demonstrate that in some cases carbonate samples with 230Th/232Th well above 20 must be corrected, otherwise an overestimation of the sample's age is obtained. Evaluation of the relationship between 230Th/234U and 230Th/232Th in the carbonate's aliquots will enable evaluation of the limit at which a carbonate can be considered pure or impure. [ABSTRACT FROM AUTHOR]

Abstract Aragonite speleothems are increasingly being used as high-resolution climate proxies; however, aragonite is unstable and susceptible to diagenetic transformation into calcite leading to mineralogical, textural and geochemical alterations that have not been fully investigated. To provide some insights to these modifications, this study combines stable isotope geochemistry and U-series dating with petrological observations and EMPA elemental analyses to characterize a stalagmite from Castañar Cave (Cáceres, Spain) that shows primary aragonite diagenetically altered and with reverse ages. The diagenetic processes include recrystallization to calcite, micritization and dissolution. Characterization and interpretation of the chemistry and nature of the waters from which the aragonite precipitated, and of the ones that subsequently formed the calcite, indicates that both polymorphs formed from the same fluids. These fluids hydrochemically evolved from an "aragonite mode" to a "calcite mode" along a diagenetic path within the sample. The results show that during transformation the system stayed close in one of the stages, and open in the other with the same textural result. Reverse ages are found either in the recrystallized areas or in the primary aragonite, caused by two different U-remobilization mechanisms, U-leaching due to flowing waters on the surface, and U-loss during the transformation process. These results highlight the complex behavior of speleothems during diagenesis and the impact on the geochemical information of the primary and secondary phases, and thus the importance of petrological and geochemical characterization of speleothems for paleoclimatic studies. [ABSTRACT FROM AUTHOR]

This paper presents a detailed geological map at the 1:20,000 scale of the Tocomar basin in the Central Puna (north-western Argentina), which extends over an area of about 80 km2 and displays the spatial distribution of the Quaternary deposits and the structures that cover the Ordovician basement and the Tertiary sedimentary and volcanic units. The new dataset includes litho-facies descriptions, stratigraphic and structural data and new 234U/230Th ages for travertine rocks. The new reconstructed stratigraphic framework, along with the structural analysis, has revealed the complex evolution of a small extensional basin including a period of prolonged volcanic activity with different eruptive centres and styles. The geological map improves the knowledge of the geology of the Tocomar basin and the local interplay between orogen-parallel thrusts and orogen-oblique fault systems. This contribution represents a fundamental support for in depth research and also for encouraging geothermal exploration and exploitation in the Puna Plateau region.

The steep, south facing slopes of the central Vinschgau (Val Venosta, South Tyrol, northern Italy) are characterized by deep-seated compound rockslides affecting 51 km2 and reaching beneath the Quaternary valley fill. Morphological features include double ridges, trenches, scarps, and counterscarps, whereby the extent of displacement rises from W to E. Near the toe of these slopes, abundant fractures are present whose orientation and spatial strongly suggest that they are related to the gravitational slope deformations. These fractures host carbonate speleothems which are associated with local tufa occurrences at the surface. Given that the metamorphic host rock is essentially carbonate-free, these carbonate deposits require extensive water-rock interactions to form. Modern springs along the toe of the slope are also mostly supersaturated with respect to calcite and locally also aragonite. The invariant chemical composition, very low tritium levels, and in particular the low oxygen isotope values indicate that this groundwater infiltrates at high elevation and is characterized by a long residence time. On the other hand, local infiltration in the lower reaches of the slope is very limited due to the semiarid climate and is incompatible with the measured groundwater stable isotope composition and the high degree of mineralization. We therefore propose a conceptual model which reconciles the deep-seated gravitational slope deformation with the occurrence of mineralized groundwater and associated carbonate precipitates in fractures near the toe of the slope. These deposits provide a means to place constraints on the timing of rock fracturing and hence the slope movements. U/Th dating of 34 samples from eight sites shows that speleothem deposition started 14.2 ka BP and occurred semi-continuously throughout the Holocene. Thus, gravitational displacements likely commenced with a lag of ~3-4 ka after the deglaciation of the valley, which is also consistent with the few available dates on the onset of other deep-seated slope deformations in the Alps. [ABSTRACT FROM AUTHOR]

Abstract Three stalagmites, which grew in the high altitude (∼1800 m a.s.l.) Piani Eterni karst system (northern Italy), represent the longest speleothem palaeoclimate-environmental record from the southern Alps. U-Th dating shows their discontinuous formation during Marine Isotope Stage (MIS) 10, 8, 7d, 6 and 5d–b, with carbonate deposition prevented during both full interglacial and full glacial stages. Speleothem formation was inhibited during interglacial peaks because local base level rise, connected to global climate changes, caused the alluviation of the main epiphreatic levels of the cave system. Drainage of the hydrological pathways, caused by the progressive decrease of rainfall and the accumulation of a perennial snow pack, stopped carbonate deposition during glacials. Thus, Piani Eterni speleothems function as indicators of transitional interglacial to glacial (IG–G) climate periods over the last ∼400 thousand years (kyrs). Analysis of δ18O and δ13C suggest that: i) seasonal snow melt occurred in these high altitude terrains during IG–G times, allowing meteoric water to efficiently penetrate the karst network; ii) soils were restored during MIS 5c–b, but absent during MIS 10, 8, 7d and 6 due to denudation of the karst surfaces; and iii) rainfall perturbations modulated the IG–G shifts in the southern Alps. Rainfall variation is connected to solar radiation changes at orbital timescales during MIS 5c–b, and mimics Dansgaard-Oeschger (DO) cycle variability during DO 23 and 22. DO cycle-like variability is also suspected during MIS 10, 8 and 6. The most important result is that, from a geochemical perspective, this study demonstrates that drivers of δ18O in southern alpine speleothems are similar to Mediterranean, Middle Eastern and Asian speleothems in that they are prevalently controlled by the rainfall amount effect. This contrasts with speleothem records from the more continental northern alpine sector where the air temperature effect on δ18O of precipitation dominates. Highlights • The longest speleothem palaeoclimate-environmental record from the Southern Alps. • Speleothems as indicators of interglacial-to-glacial transition over the last ∼400 kyr. • Seasonal snow melting occurred during interglacial-to-glacial times. • Soils restored during MIS 5c-b, but were absent during MIS 10, 8, 7d and 6. • Mediterranean response of δ18O in Southern Alpine speleothems (rainfall amount). [ABSTRACT FROM AUTHOR]

Abstract Terrace ages deduced from diverse geochronological records yielded inconsistent data in the Danube valley in Hungary. The problem of discrepancies in the different chronological datasets has to be resolved before the Quaternary tectonic and climatic processes leading to valley incision and terrace formation may be properly evaluated. To establish a more robust chronology of the Danube valley in Hungary, new cosmogenic nuclide- (10Be depth profiles, 26Al/10Be burial durations and burial depth profile) and luminescence-based (pIRIR 290) terrace ages were acquired and compared to revised paleontological and published U/Th and magnetostratigraphic data. All the applied geo-chronometers led to concordant terrace ages, with the exception of the U/Th method applied on travertine deposits covering terraces. U/Th ages predating the last interglacial manifest a bias towards younger ages, and so they were ignored in relation to the quantification of terrace ages. As a result, terrace ages from the Late Pliocene to Late Pleistocene were settled. With regard to data from the Middle Pleistocene onwards, the combination of diverse methodologies led to a tighter bracketing of terrace ages than would be possible using a single dating method. The modelling of cosmogenic 26Al and 10Be concentrations enabled to derive surface denudation rates and their combination with paleontological data also allowed us to decide between diverse landscape evolution scenarios. Highlights • New 10Be depth profiles, 26Al/10Be burial durations, pIRIR 290 and paleontological ages. • Combined methodology led to robust terrace ages ranging from 2.9 ± 0.5 Ma to 98 ± 7 ka. • For pre-Late Pleistocene terraces no correlation of terrace chronology with U/Th ages of cover-travertines. • Novel approach: 26Al/10Be burial depth profile modelling. • Different landscape evolution scenarios revealed by CRN modelling. [ABSTRACT FROM AUTHOR]

Abstract: A flight of marine terraces along the Cuban coast records Quaternary sea‐level highstands and a general slowly uplifting trend during the Pleistocene. U/Th dating of these limestone terraces is difficult because fossil reef corals have been affected by open system conditions. Terrace ages are thus often based on geological and geomorphological observations. In contrast, the minimum age of the terraces can be constrained by dating speleothems from coastal mixing (flank margin) caves formed during past sea‐level highstands and carving the marine limestones. Speleothems in Santa Catalina Cave have ages >360 ka and show various cycles of subaerial–subaqueous corrosion and speleothem growth. This suggests that the cave was carved during the MIS 11 sea‐level highstand or earlier. Some stalagmites grew during MIS 11 through MIS 8 and were submerged twice, once at the end of MIS 11 and then during MIS 9. Phreatic overgrowths (POS) covering the speleothems suggest anchialine conditions in the cave during MIS 5e. Their altitude at 16 m above present sea level indicates a late Pleistocene uplift rate of <0.1 mm/ka, but modelling also shows uplift to have been insignificant over a long timespan during the middle Pleistocene since the cave was carved. Our study shows that some flank margin caves in the region of Matanzas are older than commonly believed (i.e. MIS 11 rather than MIS 5). These caves not only can be preserved but are good markers of interglacial sea‐level highstands, more reliable than marine abrasion surfaces. Copyright © 2018 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Here we track the water-table position and temperature of the Mount San Giovanni aquifer (Iglesiente-Sulcis mining district, SW Sardinia, Italy) during the past 600 ka by determining the ages (U/Th dating) and stable isotope compositions (δ 18 O, δ 13 C and Δ 47 ) of a variety of subaqueous carbonate speleothems (e.g. calcite spars, dogtooth calcite crystals and calcite coatings). Clumped isotopes ( Δ 47 ) provide quantitative estimates of carbonate formation temperatures (and thus water temperatures) that are independent of the oxygen isotope composition of water (δ 18 O w ). Then, the δ 18 O w of the paleo-water has been reconstructed from the clumped isotope temperature (T Δ 47 ) and the δ 18 O of the carbonate (δ 18 O c ). We find that some high-temperature calcite spars formed prior to 600 ka at temperatures above ~120 °C. Lower-temperature spars (~70 °C) precipitated at ~400 ka, and cold-water subaqueous speleothems (~10–20 °C) formed in perched ponds at different levels of the karst systems between 410 ka and 110 ka, while coeval precipitation of subaerial flowstones occurred in the upper level of the shallower caves until 82 ka. We infer that the groundwater level dropped by ~120 m from ~400 to ~250 ka, with a relatively rapid rate of ~0.8 mm/yr. Considering the tectonic stability of Sardinia during the Quaternary, this high rate derives from climate driven geomorphological processes at the surface rather than tectonic uplift. The δ 18 O values of the paleo-aquifer water range from −6.0 ± 0.7‰ during MIS 5c, and similar to modern cave water values (−5.1‰), to −7.7± 0.4‰ during the colder MIS 8. These values indicate that the groundwater reflected the δ 18 O signal of meteoric water, with no significant contributions from metasomatic and metamorphic waters. The observed δ 18 O w variability can be explained by glacial/interglacial paleoclimate changes affecting rainfall δ 18 O (and thus groundwater δ 18 O). We conclude that clumped isotope thermometry on subaqueous carbonate speleothems is a useful tool for tracking paleo-aquifer temperatures and δ 18 O w reconstructions. [ABSTRACT FROM AUTHOR]

Abstract: Longevity and size of magmatic systems are fundamental factors for assessing the potential of a geothermal field. At Los Humeros volcanic complex (LHVC), the first caldera‐forming event was reported at 460 ± 40 ka. New zircon U/Th and plagioclase 40Ar/39Ar dates of pre‐, syn‐ and postcaldera volcanics allow a reappraisal of the evolution of the geothermally active LHVC. The age of the voluminous Xaltipan ignimbrite (115 km3 dense rock equivalent [DRE]) associated with the formation of the Los Humeros caldera is now constrained by two geochronometers (zircon U/Th and plagioclase 40Ar/39Ar dating) to 164 ± 4.2 ka, which postdates a long episode of precaldera volcanism (rhyolitic domes), the oldest age of which is 693.0 ± 1.9 ka (40Ar/39Ar). The inferred short residence time (around 5 ka) for the paroxysmal Xaltipan ignimbrite is indicative of rapid assembly of a large magma body and rejuvenation of the system due to recurrent recharge magmas, as it has been occurred in some other large magmatic systems. Younger ages than previously believed have been obtained also for the other voluminous explosive phases of the Faby fall tuff at ∼70 ka and the second caldera‐forming Zaragoza ignimbrite with 15 km3 DRE, which erupted immediately after. Thus, the time interval that separates the two caldera‐forming episodes at Los Humeros is only 94 kyr, which is a much shorter interval than suggested by previous K‐Ar dates (410 kyr). This temporal proximity allows us to propose a caldera stage encompassing the Xaltipan and the Zaragoza ignimbrites, followed by emplacement at 44.8 ± 1.7 ka of rhyolitic magmas interpreted to represent a postcaldera, resurgent stage. Rhyolitic eruptions have also occurred during the Holocene (<7.3 ± 0.1 ka) along with olivine‐rich basalts that suggest recharge of the system. The estimated large volume magmatic reservoir for Los Humeros (>∼1,200 km3) and these new ages indicating much younger caldera‐forming volcanism than previously believed are fundamental factors in the application of classical conductive models of heat resource, enhancing the heat production capacity and favor a higher geothermal potential. [ABSTRACT FROM AUTHOR]

Previous studies point to a discrepancy in the timing of the maximum extent of the Alpine glaciation during the last glacial cycle (Würmian) in the Western Alps. Work carried out on the Lyon palaeoglacier lobe in France suggests that the glacial maximum occurred during Marine Isotope Stage (MIS) 4, while more recent studies on the Rhône palaeoglacier lobe in Switzerland provide evidence of a maximum during MIS 2. Here, we present new chronological data from the karst region of the Western Bauges (French Alps). Between 500 m and 1200 m a.s.l. several karst systems were in lateral position to the Isère palaeoglacier. This palaeoglacier invaded the Bauges limestone massif and the Chéran valley by a transfluence controlled by the Frêne pass at 980 m a.s.l. Allochthonous glacier-derived gravel and sand interbedded with speleothems are present in caves, providing terminus ante quem and post quem age constraints on the timing of several glacial advances. Other speleothems were submerged by rising water levels in the karst due to damming by the glacier. Finally, some speleothems show shatter marks caused by the impact of pebbles transported by highly turbulent meltwaters. 25 U/Th dates of speleothems cover MIS 9 to 1. For MIS 4 to 2, they allow, indirectly, to constrain the different glacial advances into the Bauges limestone massif and to re-evaluate the timing of the maximum Alpine glaciation during the Würmian in this part of the Western Alps. Although the new data and observations do not exclude the possibility of a maximum glacier advance during MIS 2, they argue for a maximum advance during MIS 4 and a local, smaller one during MIS 2. [Display omitted] • Clastic deposits in caves of the western Bauges record several phases of glaciation. • U-Th speleothems dates (MIS 9 to 1) constrain the age of these deposits. • The glacial retreat was followed by a phase of karst "cleaning". • These results hint towards a larger MIS 4 advance than during MIS 2. [ABSTRACT FROM AUTHOR]

Fossil gathering by humans has been rarely documented in the Iberian Peninsula. In the present paper, a multidisciplinary approach has been taken to analyze a straight-tusked elephant ( Elephas antiquus) molar retrieved in a Magdalenian deposit at the rock shelter of El Pirulejo in southern Spain. The taphonomical analyses revealed a multifarious use of a tooth that had not only been worked into an anvil-sort-of-tool but also used as a core and partly tainted with a composite pigment. The dating and geochemical analyses further evidenced that the molar derived from an animal that had lived in a rather arid landscape with a temperature range between 12.3 and 14.3 °C coincident with a cold episode within marine isotope stage (MIS) 6.6 and probably fed on herbaceous plants. These analyses evidence the potential fossils from archaeological sites bear for addressing a wide range of issues that include both the cultural and paleoenvironmental realms. [ABSTRACT FROM AUTHOR]

In the Quaternary Sarıkavak fluvial tufa deposits, situated in south-western Turkey, different facies have been identified and their mutual relationships have been unravelled. This tufa formation is located at the northern part of Acıgöl Graben. The development of the Sarıkavak tufas represents typical fluvial and fluvio-palustrine environments. In total eight tufa lithofacies have been differentiated, namely: moss tufa facies, oncolitic tufa facies, stromatolitic tufa facies, phytoclastic tufa facies, intraclastic tufa facies, extra-formational clastic tufa facies, sapropelitic tufa facies, and palaeosol. Preliminary U/Th datings indicate that these deposits formed prior to 219 ka and continued until 80 ka (MIS 7 till 5). δ 13 C signatures (0.78‰ to −1.63‰ V-PDB) best can be explained by limestone dissolution processes or respiration from C4 plant vegetation into the soil or both. For that reason, the Sarıkavak tufa deposits can be classified as ‘travitufa’ which precipitated in a distal facies system of travertine occurrences. δ 18 O values (−7.49‰ to −10.83‰ V-PDB) of the whole data set reflect some significant changes, which is interpreted in terms of temperature variations reflecting warm and cold periods among MIS 7 (interglacial), MIS 6 (glacial) and MIS 5 (interglacial). The development of the Sarıkavak tufa deposits are related to the Maymundağı fault that borders the Acıgöl Graben in the north. This fault and its synthetic fault segments play a pivotal role with regard to the palaeo-flow direction of water and control the basin topography. These structural structures are likely responsible for all active and ancient springs in the study area, as well as their respective carbonate precipitates. [ABSTRACT FROM AUTHOR]

Active and fossil endogenic travertine mounts scattered along the Little Grand Wash fault are studied as records of Quaternary CO 2 -enriched fluid leakage. This study focusses on a particular area where a fossil mount formed in a near-surface setting by successive circulation/sealing episodes from Late Pleistocene to Mid-Holocene and where a modern surface travertine is still being formed by a CO 2 -enriched fluid source. The fossil mount is composed of horizontal and vertical veins whereby the vertical veins recorded numerous cycles of circulation/sealing/dissolution events and were used as conduits for the CO 2 -enriched fluid circulation from the depth to the surface or along sub-horizontal fractures where successive precipitation events are recorded. The modern travertine is being built at the surface by successive eruption of Crystal Geyser, an anthropic geyser active since the 1930's. δ 13 C and δ 18 O signatures and U/Th datings, ranging from 11.5 ky till present-day allows calibrating in detail the CO 2 enriched fluid leakage along a single fault segment and in a post glacial context, as last glaciations in the study area took place 15 ky ago. The dataset shows a high decrease of the oxygen stable isotope values till about 6 ky, then the variations reflect a constant range until present-day. This tends to restrain the period of local increase of the meteoric water input in the aquifer that is sourcing the CO 2 -enriched water. The fossil travertine represents a 7 ky-long record of CO 2 leakage above a natural reservoir, from Late Pleistocene to Mid-Holocene. The flux of CO 2 leakage through time and the total escaping volume have been computed and appears to be low in comparison with an anthropogenic leak provoked, for instance, by a non-sealed well. [ABSTRACT FROM AUTHOR]

The Soğucak travertine occurrences developed along north segment of the North Anatolian Fault (NAF) in Yalova province, Marmara Region, Turkey. The range-front type travertines outcropping over an approximately 1 km 2 area with 20–40 m thickness are middle-thick bedded and back-tilted southward or horizontally. Lithology of the travertines includes physolite, stalactites-stalagmites, cave pearls, sharp pebble carbonate nodules, spherical-roller-intricate shapes and laminated banded travertines. Geochemical analysis was performed on six samples of the travertines. The samples showed high calcite composition (averagely 98%) and Mg carbonite content varying from 0.87 to 1.33%. The travertines were deposited by means of normal faults as indicated by structural and morphological relationship with active tectonics. 234 U/ 230 Th dating of the travertines provided an age range from 61.318 (±3.091) to 231.944 (±141.902) ka. Findings show that the travertine deposition and deployment of faults in the region occurred approximately at 231 ka, corresponding to Middle Pleistocene. Therefore, the age of both travertines and NAF was determined as Middle Pleistocene. [ABSTRACT FROM AUTHOR]

This investigation reports on the comparison between ICP-MS U-Th and AMS 14C ages of Phreatic Overgrowths on Speleothems (POS) from two different caves on the island of Mallorca (Spain). These speleothem encrustations form at the water table of coastal caves in a low-amplitude tide-controlled microenvironment and are used to reconstruct past sea level changes. The aim of this study is to evaluate if this particular type of speleothem is datable using 14C method and to investigate possible problems connected with the incorporation of dead carbon inherited from the dissolution of 14C-free limestone. The results show that 14C ages are strongly site dependent and appear related to local residence time of water infiltration through the soil and epikarst. When short transit time and limited interaction with soil and bedrock, as in Cova de Cala Varques A, the so-called “reservoir” effect is negligible and 14C and U-Th ages corresponds within the error range. When the residence time is longer, as in Cova des Pas de Vallgornera, 14C ages are steadily 2,300-2,400 years older than the U-Th data, as shown by the mean value (25%) of estimated percent dead carbon proportions and by higher and better correlated contents of major and trace elements in the vadose support of this speleothem encrustation. The potential use of this multi-method approach to paleoenvironmental studies is also suggested.

Su Fossu de Cannas (SFC) cave is one of several known cavities in the Sadali plateau in Sardinia, Italy. The evolution of the cave is the result of complex erosional and deposital processes that occurred during the Neogene and Quaternary. A fossiliferous cemented conglomerate, containing various deer remains, now forms the ceiling of a cavity (tunnel). The faunal remains belong to a large cervid, which show some morphological affinity with large deer that have an endemic Sardinian lineage ( Praemegaceros sardous–Praemegaceros cazioti ). Palaeoecological data based on some peculiar features and the large size of the SFC deer suggest that it is the most primitive Megacerine found in Sardinia to date, and the first representative of the endemic lineage. The 450 ka U Th age for the flowstone capping the fossiliferous layer defines: the end of sedimentation in which Sadali deer remains are preserved; and the dispersal from the mainland of the ancestor of the endemic Sardinian Megacerini. Stratigraphic and micromorphological analyses of the cave deposits allow the reconstruction of the timing of the cave's development throughout the Pliocene to the Holocene. [ABSTRACT FROM AUTHOR]

In 1993, a fossil hominin skeleton was discovered in the karst caves of Lamalunga, near Altamura, in southern Italy. Despite the fact that this specimen represents one of the most extraordinary hominin specimens ever found in Europe, for the last two decades our knowledge of it has been based purely on the documented on-site observations. Recently, the retrieval from the cave of a fragment of bone (part of the right scapula) allowed the first dating of the individual, the quantitative analysis of a diagnostic morphological feature, and a preliminary paleogenetic characterization of this hominin skeleton from Altamura. Overall, the results concur in indicating that it belongs to the hypodigm of Homo neanderthalensis , with some phenetic peculiarities that appear consistent with a chronology ranging from 172 ± 15 ka to 130.1 ± 1.9 ka. Thus, the skeleton from Altamura represents the most ancient Neanderthal from which endogenous DNA has ever been extracted. [ABSTRACT FROM AUTHOR]

Capo S. Marco is the southernmost termination of the Sinis Peninsula in the northwestern border of the Oristano Gulf (western Sardinia, Italy). In the area, there are some of the most controversial and debated Quaternary deposits of Sardinia, consisting of beach, aeolian and slope sediments, whose chronological attribution changed according to different authors and, in different times, by the same authors. These discrepancies have not been solved by new radiometric dates, as radiocarbon and Optically Stimulated Luminescence (OSL) methods provided ages that are significantly different. During recent investigations at Capo S. Marco, beach notches filled with bioclastic sands, gravels, and boulders were discovered up to an elevation of ∼4.5 m, which is the highest elevation of the known beach notches. These sediments rest on aeolian deposits and form a marine terrace in two sites. In some places, these sediments also include small colonies of the coral Cladocora caespitosa in living position that have been recently dated by U/Th at 70 ± 4 ka and attributed to the end of MIS 5. Here, we report new U-series analyses of two samples of C. caespitosa collected on the uppermost part of the sequence. The U/Th ages of 153 ± 0.8 and 149 ± 0.6 ka would correspond to MIS 6, but the high values for the initial δ 234 U (177 and 179) compared to the modern seawater value (147) point to an open-system addition of 234 U and/or 230 Th. The corrected ages using the open-system model of Thomson et al. are 141.6 ± 2 and 132 ± 2 ka. However, these deposits and the beach notches are not buried under aeolian or colluvial sediments, as are almost all the Tyrrhenian marine deposits found in Sardinia. They also rest on aeolian sediments, which, at San Giovanni di Sinis, were dated to MIS4 or Late MIS2 by OSL and radiocarbon dating of buried organic palaeosols, respectively. Accordingly, the stratigraphic evidence would suggest their attribution to the Holocene, although this contrasts with the Holocene sea level models available and the U/Th dating results. [ABSTRACT FROM AUTHOR]

Montecchio cave (Grosseto province, Tuscany, Italy) opens at 320 m asl, in a small outcrop of Jurassic limestone ( Calcare Massiccio Fm.), close to the Albegna river. This area is characterised by the presence of several thermal springs and the outcropping of travertine deposits at different altitudes. The Montecchio cave, with passage length development of over 1700 m, is characterised by the presence of several sub-horizontal passages and many medium- and small-scale morphologies indicative of sulphuric acid speleogenesis (SAS). The thermal aquifer is intercepted at a depth of about 100 m below the entrance: the water temperature exceeds 30 °C and sulphate content is over 1300 mg l − 1 . The cave hosts large gypsum deposits from 40 to 100 m below the entrance that are by-products of the reaction between sulphuric acid and the carbonate host rock. The lower part of the cave hosts over 1 m thick calcite cave raft deposits, which are evidence of long-standing, probably thermal, water in an evaporative environment related to significant air currents. Sulphur isotopes of gypsum have negative δ 34 S values (from − 28.3 to − 24.2‰), typical of SAS. Calcite cave rafts and speleogenetic gypsum both yield young U/Th ages varying from 68.5 ka to 2 ka BP, indicating a rapid phase of dewatering followed by gypsum precipitation in aerate environment. This fast water table lowering is related to a rapid incision of the nearby Albegna river, and was followed by a 20–30 m fluctuation of the thermal water table, as recorded in the calcite raft deposits and gypsum crusts. [ABSTRACT FROM AUTHOR]

The dating of the fluvial terraces of the middle River Llobregat enabled one to establish a correlation between the sedimentation episodes in continental zones and in neighbouring deltaic and coastal areas in the NE Iberian continental margin. The fluvial Terraces 4 (+85-95 m above river level) and 3 (+55-65 m above river level) are made up by or include travertines, which were deposited around 350,000 and 111,000 years ago, respectively. These radiometric ages correspond to two high sea level periods: the Eemian interglacial (isotopic stage 5e) and the interglacial related to isotopic stage 9. However, other travertine units in the valley, such as the Can Tobella staggered cascade travertines, were formed during the Holocene, probably due to hydrothermal spring activity related to the tectonic contact between the Catalan Coastal Ranges and the Ebro Basin.

Abstract: A joint industrial project with IFREMER and Total provides insights into the tectonic setting and the geochemistry of a large active pockmark offshore W-Africa in the Niger Delta. The study combines both geophysical (seismic) and geochemical data to infer the dynamics of a 300 m wide pockmark located at 667 m water depth. Two Calypso cores, one at the centre and one outside the pockmark, along with three box-cores, two inside the pockmark and one outside, were collected to study the geochemistry of gas hydrates, carbonates and pore waters. Two seismic lines, a 3D high resolution random line and a 2D high resolution seismic line, provide a good description of the plumbing of the system. The integrated results depict a very active pockmark characterized by several gas charged-bodies, a well identified BSR marking a hydrate accumulation zone, charged from deeper sources via a network of faults. Hydrates and carbonate concretions have been detected inside the pockmark while only the latter has been found outside. The hydrate analyses show that the hydrate-forming gases are of thermogenic origin, albeit overwhelmingly composed of methane. Pore-water analyses reveal the occurrence of anaerobic oxidation of methane coupled with sulphate reduction at shallow depth (∼200 cm). The chloride concentration profile exhibits both values lower than that of seawater which is inherent to hydrate dissociation after core recovery and positive anomalies (values 7% higher than that of seawater background) at the lowermost part of the core. The latter evidence suggests current or recent hydrate formation at this area. The carbonate dating provides additional temporal information and indicates that this pockmark has been active since ∼21 kyr. [Copyright &y& Elsevier]

Abstract: Cemented calcareous breccias appear in the Picos de Europa (Cantabrian Mountains, Spain) resting on glacially abraded surfaces and covered by moraines. U/Th dating of the calcite coating the clasts was successful in two samples, the oldest one indicating that the breccias accumulated during or prior to Marine Isotope Stage (MIS) 11, and the youngest indicating later cementation during MIS 8. The former introduces a limit for the age of the glaciation preceding the breccias, which cannot correspond to an event younger than MIS 12. This is the oldest absolute age so far obtained for intercalated glacial/interglacial deposits of the Iberian Peninsula. [Copyright &y& Elsevier]