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The Monte Corchia cave system, one of the most famous and popular caves in Italy, has in recent times been the subject of investigation on its speleothems as paleoclimate archives. This paper describes the geology, geomorphology and water chemistry of the cave system with the aim to elucidate the processes that have generated these speleothems and the properties they contain that are so useful for paleoclimatology. Some general conclusions can be drawn: i) the Corchia system is a cave developed over different altitudes during progressive uplift of the mountain chain in which it is located, probably under drainage conditions very different to those of the present. This has allowed the development of a large (ca. 60 km) and deep (-1187 m) karst system; ii) the dewatering phases have left the deepest chambers far away from clastic input and with long drip pathways; iii) the peculiar geological context has permitted the water to intercept and dissolve a significant source of U (still unknown) that facilitates radiometric dating; iv) in the last 1 Ma at least, no significant changes have occurred in the relief and in the epikarst, in the sense that speleothems have grown under very similar conditions. In addition the extremely low Ca concentration of drip waters have permitted low speleothem growth rates and, at least for the “Galleria delle Stalattiti”, the zone under paleoclimate studies,a stable plumbing system (i.e. chemistry and stable isotopes of drip waters) has produced calcite close to isotopic equilibrium.

We present the geomorphological map of the northwestern part of the Kurdistan Region of Iraq, where the landscape expresses the tectonic activity associated with the Arabia-Eurasia convergence and Neogene climate change. These processes influenced the evolution of landforms and fluvial pathways, where major rivers Tigris, Khabur, and Great Zab incise the landscape of Northeastern Mesopotamia Anticlinal ridges and syncline trough compose the Zagros orogen. The development of water and wind gaps, slope, and karsts processes in the highlands and the tilting of fluvial terraces in the flat areas are the main evidence of the relationship between tectonics, climate variations and geomorphological processes. During the Quaternary, especially after the Last Glacial Maximum, fluctuating arid and wet periods also influenced local landforms and fluvial patterns of the area. Finally, the intensified Holocene human occupation and agricultural activities during the passage to more complex societies over time impacted the evolution of the landscape in this part of Mesopotamia. [ABSTRACT FROM AUTHOR]

We present the results of the geomorphological mapping of a region of the Dhofar (Sultanate of Oman) including two contrasting physiographic units sharing a common drainage system into the Arabian Sea: the Jebel Qara limestone massif and the coastal plain of Salalah. Neogene to Quaternary tectonic activity controlled the formation of an extensive system of faults and caused the uplift of the Jebel Qara, forming structural escarpments. The massif underwent karstification and subsequent linear erosion. Today the Jebel is cut by a dendritic net of dry valleys, occasionally dammed by calcareous tufa dams. The transition between the southern escarpment of the Jebel and the plain below displays flat alluvial fans, bordered by a strip of beachrock, coastal dunes, and coastal lagoons, located in correspondence to estuaries. Dramatic soil erosion is evident, linked to intense human-triggered zoogeomorphological processes started in the Mid-Late Holocene after the introduction of pastoral land-use. [ABSTRACT FROM AUTHOR]

Rationale: The suitability of organic matter (OM) removal pre‐treatments in isotopic studies of lacustrine carbonates is currently under debate. Naturally occurring OM seems to have a negligible effect on the bulk isotopic composition of carbonates compared with changes induced by pre‐treatments. This study provides further insights into the possible effects induced by commonly used pre‐treatments on natural lacustrine carbonates. Methods: Sixteen samples from the Fucino F1–F3 lacustrine succession (Abruzzo, central Italy) were characterised for their mineralogical and geochemical composition and each was split into three identical aliquots. One aliquot was left untreated while the remaining two were treated with NaOCl and H2O2 dilutions. The same treatment was applied to an internal standard consisting of pure Carrara marble. The treated and untreated samples were analysed for their carbon (δ13C values) and oxygen (δ18O values) isotope compositions using an Analytical Precision AP2003 isotope ratio mass spectrometer. Results: The samples had variable proportions of endogenic and detrital components, the detrital portion being more (less) abundant during colder (warmer) climate phases. We observed that neither the NaOCl nor the H2O2 treatment was able to completely remove OM and therefore there was selective removal of compounds within the OM pool. A possible effect of pre‐treatment is the loss of carbonates intimately interspersed within the OM, as suggested by the evolution of isotopic ratios towards the local detrital array. Conclusions: Our study highlights sample‐specific changes in geochemistry associated with sample pre‐treatments; however, such changes do not seem to lead to either systematic and/or predictable isotopic shifts. We suggest that the suitability of NaOCl or H2O2 pre‐treatments for OM removal should be evaluated on a case‐by‐case basis. In the specific case of lacustrine marls from palaeo‐lake Fucino containing relatively low amounts of OM and in which both detrital and endogenic carbonates occur, both pre‐treatments should be avoided. [ABSTRACT FROM AUTHOR]

Among past interglacial periods, Marine Isotope Stage (MIS) 19 is particularly interesting because its orbital geometry is very similar to that of the present interglacial. Here we present a high-resolution (sub-centennial) multiproxy record covering the ca. 790-770 ka interval, i.e. the interglacial MIS 19c and the ensuing glacial inception of MIS 19b, from a lacustrine sediment sequence retrieved from the Sulmona Basin (central Italy). The record has an independent chronology based on radiometric dating of six volcanic ash layers, and the resulting age model has a mean associated uncertainty of ±2.6 kyr. Variations in sediment geochemistry and mineralogy are interpreted in terms of past hydrological and temperature changes. Several millennial and sub-millennial events of reduced precipitation are well expressed. Comparisons with continental and marine records from the mid-latitude and sub-polar North Atlantic suggest a broad spatial expression for the observed events. Events occurring within the interglacial are not clearly associated with changes in marine proxies in the Iberian Margin, although similarities with the record from the sub-polar North Atlantic can be recognized and tentatively linked to changes in local hydrography having a downstream effect amplified by changes in atmospheric circulation. During the glacial inception, changes in the Sulmona record are coherent with changes in North Atlantic records, with drier events likely associated with meltwater-induced intervals of AMOC weakening. An event at ca. 785.6 ka may also reflect oceanic changes caused by freshwater discharges from residual ice-sheets and an outburst flood, similar to the 8.2 ka event in the Holocene. • Independently dated, multiproxy lacustrine record covering the MIS19 interglacial. • Consistent sub-orbital hydrological and environmental variability. • The intra-interglacial variability appears significant at regional and extra regional scale. • Comparison with subpolar record suggests a high-latitude forcing for interglacial variability. [ABSTRACT FROM AUTHOR]

We present new data on the 4.2 ka event in the central Mediterranean from Corchia Cave (Tuscany, central Italy) stalagmite CC27. The stalagmite was analyzed for stable isotopes (δ13C and δ18O) and trace elements (Mg, U, P, Y), with all proxies showing a coherent phase of reduced cave recharge between ca. 4.5 and 4.1 ka BP. Based on the current climatological data on cyclogenesis, the reduction in cave recharge is considered to be associated with the weakening of the cyclone center located in the Gulf of Genoa in response to reduced advection of air masses from the Atlantic during winter. These conditions, which closely resemble a positive North Atlantic Oscillation (NAO) type of configuration, are associated with cooler and wetter summers with reduced sea warming, which reduced the western Mediterranean evaporation during autumn–early winter, further reducing precipitation. [ABSTRACT FROM AUTHOR]

We present new data on the 4.2 ka BP event in the central Mediterranean from Corchia Cave (Tuscany, central Italy) stalagmite CC27. The stalagmite was analysed for stable isotopes (δ13C δ18O) and trace elements (Mg, U, P, Y), with all proxies showing a coherent phase of reduced cave recharge between ca. 4.5 and 4.1 ka. Based on the current climatological data on cyclogenesis, the reduction in cave recharge is considered associated to weakening of the cyclone centre located in the Gulf of Genoa in response to reduced advection of air masses from Atlantic during winter. These conditions, which closely resemble a positive North Atlantic Oscillation (NAO)-like configuration, are associated with cooler and wetter summers, with reduced sea warming, which reduced the western Mediterranean evaporation during autumn-early winter further reducing precipitation. [ABSTRACT FROM AUTHOR]

The DEEP site sediment sequence obtained during the ICDP SCOPSCO project at Lake Ohrid was dated using tephrostratigraphic information, cyclostratigraphy, and orbital tuning through the marine isotope stages (MIS) 15- 1. Although this approach is suitable for the generation of a general chronological framework of the long succession, it is insufficient to resolve more detailed palaeoclimatological questions, such as leads and lags of climate events between marine and terrestrial records or between different regions. Here, we demonstrate how the use of different tie points can affect cyclostratigraphy and orbital tuning for the period between ca. 140 and 70 ka and how the results can be correlated with directly/indirectly radiometrically dated Mediterranean marine and continental proxy records. The alternative age model presented here shows consistent differences with that initially proposed by Francke et al. (2015) for the same interval, in particular at the level of the MIS6-5e transition. According to this new age model, different proxies from the DEEP site sediment record support an increase of temperatures between glacial to interglacial conditions, which is almost synchronous with a rapid increase in sea surface temperature observed in the western Mediterranean. The results show how a detailed study of independent chronological tie points is important to align different records and to highlight asynchronisms of climate events. Moreover, Francke et al. (2016) have incorporated the new chronology proposed for tephra OH-DP-0499 in the final DEEP age model. This has reduced substantially the chronological discrepancies between the DEEP site age model and the model proposed here for the last glacial-interglacial transition. [ABSTRACT FROM AUTHOR]

Past orbital analogues to the current interglacial, such as Marine Isotope Stage 19c (MIS 19c, ca. 800 ka), can provide reliable reference intervals for evaluating the timing and the duration of the Holocene and factors inherent in its climatic progression. Here we present the first high-resolution paleoclimatic record for MIS 19 anchored to a high-precision 40Ar/39Ar chronology, thus fully independent of any a priori assumptions on the orbital mechanisms underlying the climatic changes. It is based on the oxygen isotope compositions of Italian lake sediments showing orbital- to millennial-scale hydrological variability over the Mediterranean between 810 and 750 ka. Our record indicates that the MIS 19c interglacial lasted 10.8 ± 3.7 k.y., comparable to the time elapsed since the onset of the Holocene, and that the orbital configuration at the time of the following glacial inception was very similar to the present one. By analogy, the current interglacial should be close to its end. However, greenhouse gas concentrations at the time of the MIS 19 glacial inception were significantly lower than those of the late Holocene, suggesting that the current interglacial could have already been prolonged by the progressive increase of the greenhouse gases since 8-6 ka, possibly due to early anthropogenic disturbance of vegetation. [ABSTRACT FROM AUTHOR]

ABSTRACT A multi-proxy record was acquired from a Late Pleistocene lacustrine succession in the Sulmona basin, central Italy. Previous and new tephrostratigraphic analyses of six volcanic ash layers constrain the investigated interval to between 92.3 and 115.0 ka. The δ18O composition is interpreted as a proxy for precipitation amount in the high-altitude catchment of the karst recharge system. The oxygen record shows millennial variability that is consistent with Greenland Interstadials GI25-23 and North Atlantic cold events C24-C22, indicating a strong Mediterranean-North Atlantic climate teleconnection. However, while no appreciable isotopic difference between the three interstadials is revealed by the Greenland record, the Sulmona section reveals a wetter climate during GI24 compared with GI23 and GI25. Comparison of our record with speleothem and pollen data from central and southern Italy suggests higher seasonality of the precipitation (wet winter-dry summer) for GI24, which matches a precession minimum. The wettest period recorded at Sulmona is also coincident with the deposition of Sapropel S4 in the Tyrrhenian Sea, suggesting a teleconnection between a higher seasonality in the western Mediterranean and strengthening of the boreal monsoon system. [ABSTRACT FROM AUTHOR]

A sedimentary sequence of fluvial deposits preserved in the Corchia Cave (Alpi Apuane) provides new chronological constraints for the evolution of the cave system and the timing and rate of uplift of this sector of the Alpi Apuane since the late Pliocene. Supported by magnetostratigraphic analysis performed on fine-grained fluvial deposits, and by radiometric dating of speleothems, we suggest that the deposition of fluvial sediments occurred between ~1.6–1.2 Ma. This implies that the host volume of rock was already located close to the local base level, adding key information about the recent tectonic evolution of the Alpi Apuane. A few before ~1 Ma, an erosive phase occurred due to the base-level lowering, followed by continuous speleothem deposition since at least 0.97 Ma. From that time, Monte Corchia uplifted at a maximum rate of ~0.5 mm/year, which is consistent with isostatic uplift mainly driven by erosional unloading. The petrographical study of the fluvial deposits highlights the presence of material derived from the erosion of rocks that today are absent in the cave's catchment area, suggesting a different surface morphology during the Early Pleistocene. This study highlights the potential of cave sediments as archives for reconstructing the uplift history of mountain ranges. [ABSTRACT FROM AUTHOR]

The stable isotope composition of living and of Holocene Mytilidae shells was measured in the area of Camarones (Chubut, Argentina). The most striking results were the high δ18O values measured in samples older than ca. 6.1 cal ka BP. In the younger samples, the δ18O values remained substantially stable and similar to those of living specimens. Analysis of the data revealed the possibility for this isotopic shift to be driven mainly by changes in temperature probably accompanied by minor changes in salinity, suggesting cooler seawater before 6.1 cal ka BP, with a maximum possible temperature shift of ca. 5 °C. A possible explanation of this change can be related to a northward position of the confluence zone of the Falkland and Brazilian currents. This is consistent with the data obtained in marine cores, which indicate a northerly position of the confluence in the first half of the Holocene. Our data are also in line with the changes in wind strength and position of the Southern Westerlies Wind, as reconstructed in terrestrial proxies from the Southernmost Patagonia region. [ABSTRACT FROM AUTHOR]

In this article, we present new, high-resolution, pollen results obtained from the DEEP site sequence recovered from Lake Ohrid (Albania/FYROM) for the Last Interglacial Complex (LIC), corresponding to Marine Isotope Stage 5 (MIS 5) of the marine isotope stratigraphy. LIC covers the period between 130 and 70 ka and includes the Eemian (Last Interglacial, LI) and the succession of stadial and interstadial phases of the Early Last Glacial. During the LIC, the pollen record shows an alternation of periods characterized by forest and open vegetation, clearly resembling the well-known vegetational succession of other European records. Our results reveal three key phases for the LI: a first period (128-125 ka) with a rapid increase in temperature and precipitation, a central phase (125–118.5 ka) characterized by a slight cooling, and a late phase (118.5–112 ka), with a decline both in temperatures and precipitation. Besides the LI, we identify four more forested periods dominated by mesophilous trees and intercalated by colder and drier steppe phases, during which, however, most arboreal taxa never disappear. During the Early Last Glacial we also identify several abrupt events that can be correlated to the succession of cold events recorded in the Greenland ice core records, associated to a weakening of the North Atlantic Meridional Overturning Circulation. The new high-resolution record indicates that Lake Ohrid is an important site to understand the response of vegetation to fluctuations in regional moisture availability and temperature changes, and thus provides new evidence for the connection between the Mediterranean Region and Northern Hemisphere climate oscillations. [ABSTRACT FROM AUTHOR]

Analyses of speleothem δ18O records from Soreq (Israel) and Corchia (central Italy) caves for the period between ca. 7 to 4 ka BP show two prominent isotopic excursions toward higher values, argued to reflect relatively drier conditions, centred at ca. 5.6 and ca. 5.2 ka. A possible mechanism explaining these two drier events is from comparison with the wind strength proxy record from Hólmsá loess profile in Iceland. This suggests that rainfall decrease was related to a reduced vapour advection from Atlantic towards the Mediterranean connected to northward shift in the Westerlies. [ABSTRACT FROM AUTHOR]

Abstract In the DEEP core from the Lake Ohrid ICDP drilling project, the carbon isotope composition of bulk organic matter (δ13C TOC) over the last 516 ka shows a negative correlation with total organic carbon (TOC) and total inorganic carbon (TIC). This relationship is marked by periods of lower δ13C TOC values corresponding to higher TIC and TOC. Along with TOC/TN, the correlation between δ13C TOC and δ13C TIC suggests that most of the organic matter in the core is from aquatic primary production within the lake. The combination of TOC, TIC, and δ13C TOC is able to disentangle long-term glacial/interglacial cycles and, to a lesser extent, millennial scale climate variability. Over the longer term, δ13C TOC shows modest variability, indicating that the δ13C of the dissolved inorganic carbon (DIC) pool is stabilised by the supply of karst spring water characterised by δ13C DIC influenced by the bedrock δ13C value, and the long residence time of the lake water and well mixed upper water column promoting equilibration with atmospheric CO 2. However, comparison between arboreal pollen (AP%), TIC and TOC data indicates that the δ13C TOC signal is modulated by the leaching of soil CO 2 through runoff and spring discharge, changes in primary productivity, and recycling of organic matter within the lake, all affecting δ13C DIC. Exceptionally low δ13C TOC during some interglacial periods (e.g. MIS7 and MIS9) possibly indicate rapid intensification of organic matter recycling and/or increasing stratification and enhanced methanogenesis, even if the latter process is not supported by the sedimentological data. Highlights • The organic matter δ13C in Lake Ohrid's DEEP core is most from primary productivity. • DIC from the karst springs and atmospheric CO 2 equilibration dominate Lake Ohrid. • Soil CO 2 drives of the organic matter δ13C over interglacial/glacial periods. [ABSTRACT FROM AUTHOR]

Speleothems are potentially excellent archives of the Earth's magnetic field, capable of recording its past variations. Their characteristics, such as the continuity of the record, the possibility to be easily dated, the almost instantaneous remanence acquisition and the high time-resolution make them potentially unique high-quality Paleosecular Variation (PSV) recorders. Nevertheless, speleothems are commonly characterized by low magnetic intensities, which often limits their resolution. Here we present a paleomagnetic study performed on two cores from a flowstone from the Rio Martino Cave (Western Alps, Italy). U/Th dating indicates that the flowstone's deposition covers almost the entire Holocene, spanning the period ca. 0.5–9.0 ka, while an estimation of its mean growth rate is around 1 mm per 15 years. The flowstone is composed of columnar calcite, characterized by a highly magnetic detrital content from meta-ophiolites in the cave's catchment. This favorable geological context results in an intense magnetic signal that permits the preparation and measurement of thin (∼3 mm depth equivalent) samples, each representing around 45 yr. The Characteristic Remanent Magnetization (ChRM), isolated after systematic stepwise Alternating Field demagnetization, is well defined, with Maximum Angular Deviation (MAD) generally lower than 10°. Paleomagnetic directional data allow the reconstruction of the PSV path during the Holocene for the area. Comparison of the new data with archeomagnetic data from Italian archeological and volcanic records and using the predictions of the SHA.DIF.14k and pfm9k.1a global geomagnetic field models shows that the Rio Martino flowstone represents an excellent recorder of the Earth's magnetic field during the last 9,000 years. Our high resolution paleomagnetic record, anchored by a high-quality chronology, provides promising data both for the detection of short term geomagnetic field variations and for complementing existing regional PSV curves for the prehistoric period, for which well-dated data are still scarce. [ABSTRACT FROM AUTHOR]

Loess deposits have been described in the past for the upper section of Buca Dei Corvi succession (Central Italy). In this paper the deposits were re-analysed to clarify the depositional environment and to attempt a paleoclimate reconstruction. Two radiocarbon dates on pedogenic carbonate constrain the ages to the Late Glacial, and are consistent with previous OSL dating of the top of the succession. The non-marine mollusc assemblage shows typical character of cold and dry climatic conditions, testified by strong oligotypical composition. Mineralogy and geochemistry of the sediments indicate the abundant presence of exotic quartz mineral which can be explained only by wind transport. Probably, wind transport was also responsible of deposition of carbonate which then dissolved and re-precipitated producing pedogenic concretions. Stable isotopes ( 13 C/ 12 C and 18 O/ 16 O ratios) of the concretions are consistent with a climate drier than present conditions, with an environment characterized by sparse vegetation. [ABSTRACT FROM AUTHOR]

We present the first integrated tephrochronological study (major and trace elemental glass composition, Sr and Nd isotope analyses, and 40 Ar/ 39 Ar dating) for the last one tenth (∼82 m) of the ∼900 m-thick Quaternary lacustrine succession of the Fucino Basin, the largest and probably only Central Apennine intermountain tectonic depression that hosts a continuous lacustrine succession documenting the Plio-Quaternary sedimentary history up to historical times. Major element glass compositions, determined using a wavelength-dispersive electron microprobe (WDS-EMPA), yielded the geochemical fingerprinting needed for a reliable identification of most of the 23 stratigraphically ordered tephra layers under investigation. These include tephra from Italian volcanoes such as Campi Flegrei, Etna, Colli Albani, Ischia, Vico, Sabatini, and undefined volcanic sources in the Neapolitan area and Latium region. The recognition of key Mediterranean marker tephra layers (e.g. X-5 and X-6) is supported by trace element data acquired by Laser Ablation Inductively Couple Plasma Mass Spectrometry (LA-ICP-MS). The Sr and Nd isotope compositions of selected layers where also determined for circumscribing the volcanic source of distal tephra and for supporting correlations with individual eruptive units. We also propose a new, more expeditious covariation diagram (CaO/FeO tot vs Cl) for identifying the volcanic source of trachytic to phonolitic and tephrytic to phonolitic tephra, that are the most common compositions of pyroclastic rocks from volcanoes of Campania and Latium regions. Finally, we present five new 40 Ar/ 39 Ar age determinations, including a new, analytically well-supported, and more precise 40 Ar/ 39 Ar age for the widespread Y-7 tephra, and the first 40 Ar/ 39 Ar age determinations for one tephra from the Sabatini volcanic district (∼126 ka) and one tephra from Neapolitan volcanic area (Campi Flegrei?; ∼159 ka). These newly dated tephra are widely dispersed (e.g. Monticchio, southern Italy, Adriatic Sea and Lake Ohrid, Macedonia-Abania) and have thus the potential to become important Mediterranean MIS 5 and MIS 6 tephrochronological markers. Altogether the new geochemical data and 40 Ar/ 39 Ar ages precisely constrain the chronology of the investigated Fucino succession spanning the last ∼190 ka. In light of these results and by considering that this sedimentary succession possibly extends back to ∼2 Ma, Fucino is likely to provide a very long, continuous tephrostratigraphic record for the Mediterranean area and become a key node in the dense network of tephra correlations of this region. [ABSTRACT FROM AUTHOR]