Last Interglacial Research Articles

New paleohydroclimate record of the MIS 5e/5d transition from Yelini Cave, central Anatolian region of Türkiye

AbstractThis study presents the results of a detailed paleoclimate investigation on stalagmite YL-1 (Yelini Cave, Türkiye). YL-1 grew between 117.13 (+0.57/−0.44) ka and 114.87 (+1.63/−2.89) ka within Greenland Stadial 26, indicating a positive moisture balance during the stadial conditions in this semi-arid region. Rainfall is significantly affected by sub-cloud and surface evaporation and decreasing net effective winter precipitation is recorded by high isotope values. Enriched δ18O and δ13C at 116.65 (+0.51/−0.39) ka are interpreted as a drought event that took place ca. 400 years before the end of the MIS 5e. This event, which was reported simultaneously in marine and terrestrial archives in the Northern Hemisphere, is a result of decreased cyclone activity linked to weakening of the Atlantic meridional overturning circulation. 87Sr/86Sr values of YL-1 are close to the host-rock values. Decreased 87Sr/86Sr ratio at 116.67 (+0.54/−0.38) ka reflects the intensified water–rock interaction due to lower precipitation. Along with prior calcite precipitation effect, this is also observed by increased Mg/Ca and Sr/Ca, while low P, Cu, Be, Y, and Zr concentrations indicate a lowered amount of soil-derived colloidal material. The MIS 5e/5d transition is marked by reduced insolation and enriched δ18O at 116.24 (+0.53/−0.86) ka. The Greenland Interstadial 25 phase at 115.87 (+0.83/−1.71) ka is represented by more negative δ18O and δ13C.

Constraining the end of the Last Interglacial (MIS 5e) relative sea-level highstand in central Mediterranean: New data from Grotta delle Capre, central Italy

The current rapid change of the Earth's climate has resulted in an increasing interest for the past warm periods as potential long-term scenarios of the effects of the present global warming. The last such a period occurred 129–116 ka, known as the Last Interglacial (LIG), when the continental ice volume was significantly smaller than present, leading to a global sea-level (GSL) higher than present one. Detailed morpho-stratigraphic data, supported by a robust U/Th chronology, from Grotta delle Capre, central Italy, provided new chronological insights on the relative sea-level (RSL) dynamic during the LIG in the Mediterranean region. Our results indicate that, on Tyrrhenian Sea coasts of the central Italy, after having stationed at ∼9 m a.s.l., the LIG RSL fell at an elevation <3 m a.s.l. as early as before 123 ka, and then no longer rose above this elevation either during the later stages of the LIG or afterwards. The results match previous studies based on U/Th dating of terrestrial limiting points from Grotta Infreschi, ∼200 km SE from Grotta delle Capre along the same Tyrrhenian Sea coasts, and are in agreement with the Red Sea RLS and GSL records and the probabilistic LIG sea level assessments based on globally distributed records. On the other hand, our reconstruction is not supported by implications of U/Th dating of corals and phreatic overgrowth on speleothems from the Balearic Island of Mallorca. Such an inconsistency in the overall knowledge around the LIG RSL reconstruction results in a high uncertainty in modelling the ice and sea-level dynamic during this warm period, which needs to be reduced through more and more high-resolution, stratigraphic and chronological investigations of the morphological and sedimentary sea-level records.

Response of a Sylvan Moss Species (Didymodon validus Limpr.) with a Narrow Distribution Range to Climate Change

Mosses are particularly susceptible to climate change owing to their close biological and ecological associations with climatic conditions. However, there is a limited understanding of the changes in distribution patterns of the moss species in forest ecosystems under climate change, especially in mosses with narrow ranges. Therefore, we reconstructed historical, simulated present, and predicted future potential distribution patterns of Didymodon validus, a narrow-range moss species in the forest ecosystem, using the MaxEnt model. The aim of this study was to explore its unique suitable habitat preference, the key environmental factors affecting its distribution, and the distributional changes of D. validus under climate change at a long spatial-time scale. Our findings indicate that the most suitable locations for D. validus are situated in high-altitude regions of southwestern China. Elevation and mean temperature in the wettest quarter were identified as key factors influencing D. validus distribution patterns. Our predictions showed that despite the dramatic climatic and spatial changes over a long period of time, the range of D. validus was not radically altered. From the Last Interglacial (LIG) to the future, the area of the highly suitable habitat of D. validus accounted for only 15.3%–16.4% of the total area, and there were weak dynamic differences in D. validus at different climate stages. Under the same climate scenarios, the area loss of suitable habitat is mainly concentrated in the northern and eastern parts of the current habitat, while it may increase in the southern and eastern margins. In future climate scenarios, the distribution core zone of suitable habitat will shift to the southwest for a short distance. Even under the conditions of future climate warming, this species may still exist both in the arid and humid regions of the QTP in China. In summary, D. validus showed cold and drought resistance. Our study provides important insights and support for understanding the impact of climate change on the distribution of D. validus, as well as its future distribution and protection strategies.

Pleistocene Walrus (&lt;i&gt;Odobenus rosmarus&lt;/i&gt; L., 1758) Discovered in the Northern European Russia (Pechora River)

A fragment of a walrus skull of Neopleistocene age was found at a distance of about 340 km from the mouth of the Pechora River. The skull presumably belonged to a mature male of Atlantic walrus 13–14 years old. The radiocarbon date of the walrus bone shows the age over the method’s limit (45 ka). Nitrogen and carbon isotope data from skull collagen are discussed. The reason for the appearance of the walrus far from the modern sea shore was, presumably, the Rodionovo (Shklov, MIS 7) or boreal Sula (Mikulino, MIS 5e) marine transgression into the area of the latitudinal part of the Pechora River. The relatively good preservation of bone testifies in favor of the Sula marine transgression. The Rodionovo age of the walrus can be assumed on the basis of the presence of shallow water marine deposits lying between two Middle Pleistocene moraines—Pechora (Dnieper, MIS 8) and Vychegda (Moscow, MIS 6).

Enhanced east–west climatic contrast in northern China under past global warming: Evidence from paleovegetation records and numerical simulations

The response of vegetation to past global warming, as revealed by geological records, can provide insights into future changes. We used pollen records to reconstruct spatial changes in the boundary between steppe and forest/forest-steppe for the Last Glacial Maximum (LGM), mid-Holocene, Last Interglacial (LIG), and mid-Pliocene, representing major changes in global temperature. The results showed that in the region east of 110° E, the trend of the boundary between steppe and forest/forest-steppe rotated anticlockwise by around 30°, 5° and 10°, during the warm periods of the mid-Holocene, LIG, and mid-Pliocene, relative to the LGM, mid-Holocene, and LIG, respectively. However, in the region west of 110° E, the boundary remained stationary during the mid-Holocene compared with the LGM, while it shifted northward during the LIG relative to the mid-Holocene, and it shifted southward during the mid-Pliocene relative to the LIG. Overall, our results indicate an enhanced east-west climatic contrast in northern China under past global warming. Climate simulation results showed that the warming-induced northward shift and westward extension of the western Pacific subtropical high promoted the northwestward displacement of the East-Asian monsoon rainfall belt. This suggests that in the future, under a warmer climate, the eastern region of northern China will become wetter, and that the extent of sandy desert will decrease.

Palaeobiogeography of NE Atlantic archipelagos during the last Interglacial (MIS 5e): A molluscan approach to the conundrum of Macaronesia as a marine biogeographic unit

In order to understand the complex evolutionary processes and patterns that explain current island biodiversity, large datasets and long-term analysis are required. The Last Interglacial (LIG) was one of the warmest interglacials during the last million years. How species mobility changed during this period in the Macaronesia geographical region has long intrigued scientists. It is well established that the northward range expansion of tropical species occurred in the Macaronesian geographical region, but as a marine biogeographic unit, the term “Macaronesia” has not gained a consensus among the scientific community. For the first time, a thoroughly revised and updated checklist is presented for shallow-water marine molluscs from the Atlantic and Mediterranean during the LIG. Based on these wide ranging data, the status of Macaronesia as a marine biogeographic unit during the LIG was examined and our scientific understanding of how this unit evolved is improved. The analysis shows that during the LIG, the molluscan faunas of the Canary and Cabo Verde archipelagos were part of the same tropical Late Pleistocene Mediterranean West-African Province, whereas those in the Azores, Madeira and Selvagens archipelagos would be included in the subtropical Late Pleistocene French-Iberian Province. This contrasts with the present-day scenario, where the subtropical/warm temperate Azores and “Webbnesia” marine ecoregions (Lusitanian province) are biogeographically distinct from the Cabo Verde biogeographic subprovince, which in turn belongs to the West African Tropical biogeographic province. A further analysis of the coherence of “Macaronesia” as a marine biogeographical unit was accomplished by coupling Pliocene, LIG, and present-day data, showing that the term “Macaronesia”, and for the marine realm, should only be used in a geographical connotation.

Historical, temporal, and geographic dynamism of the interaction between Agave and Leptonycteris nectar-feeding bats.

The interaction between ecological and evolutionary processes has been recognized as an important factor shaping the evolutionary history of species. Some authors have proposed different ecological and evolutionary hypotheses concerning the relationships between plants and their pollinators; a special case is the interaction and suspected coevolution among Agave spp. and their main pollinators, the Leptonycteris bats. Agave spp. have, in general, a pollination syndrome compatible with chiropterophily including floral shape and size, nocturnal nectar production, and nectar quality and sugar concentration. Our goal was to analyze the interaction Agave-Leptonycteris and its dynamics during three different climate scenarios. We modeled the Agave-Leptonycteris interaction in its spatial and temporal components during the Pleistocene using Ecological Niche Models (ENMs) and three climate scenarios: Current, Last Glacial Maximum (LGM), and Last InterGlacial (LIG). Furthermore, we analyzed the geographic correlation between 96 Agave spp. and two of the Mexican Tequila bats, genus Leptonycteris. We found that Leptonycteris spp. interact with different Agave spp. over their migratory routes. We propose an interaction refuge in Metztitlán and Tehuacán-Cuicatlán areas, where Agave- Leptonycteris interaction has probably remained active. During the nonmigratory season, both bat species consume nectar of almost the same Agave spp., suggesting the possibility of a diffuse coevolution among Agave and Leptonycteris bats. We propose that in the areas related to migratory bat movements, each bat species interacts with different Agave spp., whereas in the areas occupied by nonmigrant individuals, both bat species consume nectar of almost the same Agave taxa.

Humid phases on the southwestern Arabian Peninsula are consistent with the last two interglacials

Past environmental and climatic conditions within the Arabian Peninsula are key to understanding the setting for hominin dispersal across the Saharo-Arabian dryland belt. The tufa deposits within the volcanic harrats on the southwest coast of Saudi Arabia fill a significant spatial gap in the distribution of palaeoenvironmental records on the west coast of the Arabian Peninsula adjacent to the Red Sea. In the catchment of Wadi Dabsa in the Harrat Al Birk, there are widespread fossil palustrine to shallow-lacustrine tufa deposits with fluvial elements. Several phases of tufa accumulation, separated by fluvial downcutting, are observable within these powerful palaeoenvironmental proxies. U–Th dating of targeted dense, banded tufa facies, yield ages that are stratigraphically consistent at the landscape scale, and indicate that tufa accumulation occurred during distinct humid phases broadly coeval with the last two warm interglacial Marine Isotope Stages (MIS 7 and MIS 5). For the first time this shows humid intervals in southwest Arabia coincident with the southern coast. There is a simlar pattern emerging further north in the Arabian Peninsula, The Sinai and Levant and further on into continental Europe. Furthermore, tufa δ18O ranges from −14.6 to −1.9‰, covering a range similar to those reported for tufa from north African oasis sites and speleothems elsewhere on the Arabian Peninsula and The Levant. The lowest δ18O values are derived from MIS 5e samples, a pattern in agreement with speleothems in Yemen and Oman, and consistent with an isotopic-enabled climate model simulation for this time slice. The δ13C and Sr isotopic compositions of dated tufa samples indicate deposition from shallow-circulating meteoric water, with no geothermal influence. This, along with the δ18O values, suggest a freshwater supply that was a potable water source in this landscape. The δ13C signatures at Wadi Dabsa are more negative than for parts of north Africa, suggesting Wadi Dabsa may have experienced comparatively higher biomass, thicker soils and wetter conditions with lower evaporative losses. This new record of tufa deposition during the middle and late Pleistocene, suggests for the first time that the west coast of Arabia experienced a similar history of humid phases over the past 250 ka as southern Arabia and the Nefud in the northern interior. These regional changes in hydroclimatic regime occur at timescales coincident with hominin dispersals.

Last interglacial global mean sea level from high-precision U-series ages of Bahamian fossil coral reefs

Accurate characterization of Last Interglacial (MIS 5e; ∼129–116 ka) sea level is important for understanding ice sheet sensitivity to climate change, with implications for predicting future sea-level rise. Here we present a record of MIS 5e sea level based on high-precision U-series ages of 23 corals with precise elevation measurements from reefs around Crooked Island, Long Cay, Long Island, and Eleuthera, The Bahamas. Rigorous screening criteria identified the most pristine samples, and nearly all samples show a narrow δ234Uinitial range between 143.8 and 151.3‰. We infer global mean sea level (GMSL) from these local observations by correcting them for glacial isostatic adjustment (GIA) and long-term subsidence. For GIA, we consider a range of ice histories and Earth viscosity structures. We identify, via Bayesian inference, the range of isostatic and GMSL histories that are consistent with MIS 5e observations across The Bahamas. When applying an open-system correction to our ages, we find that MIS 5e GMSL likely peaked higher than 1 m, but very unlikely exceeded 2.7 m. Our posterior GMSL is lower than previous estimates, but consistent with recent results of modeling and observations. Additionally, sea level observations at other locations (Seychelles, Western Australia, Yucatan) are only slightly above/within the 95% range of predicted local sea level, i.e., GIA plus GMSL, for our open-system/closed-system results. Our relatively constant MIS 5e GMSL indicates that Greenland and Antarctica melted beyond their present extents and, given the insolation forcing, that their contributions to GMSL were likely out-of-phase. These results indicate that the ice sheets may be very sensitive to regional temperature, which has important implications for their combined impact on global sea levels at a time when greenhouse gases increases are causing simultaneous warming at both poles.

Enhanced summer extreme precipitation over the Asian-African land monsoon regions during past warm periods: A modelling perspective from CESM2

Investigation of summer extreme precipitation during past warm periods may deepen our understanding of its behavior in current and future warmer climates. In this study, we investigate the variation of summer (June-July-August) extreme precipitation and the associated dynamic mechanisms over the Asian and African land monsoon regions during the mid-Pliocene warm period (mPWP) and the Last Interglacial (LIG), using six extreme indices defined by the Expert Team on Climate Change Detection and Indices. Model results indicate that summer extreme precipitation becomes more intense and frequent over the African land monsoon region during both the mPWP and LIG relative to the pre-industrial, together with longer wet spell and shorter dry spell, though the magnitudes are relatively larger during the LIG than the mPWP. Based on the moisture budget equation, the vertical thermodynamic term and the vertical dynamic term largely account for the increased summer precipitation over the African land monsoon region during the mPWP and LIG, respectively. Over the Asian land monsoon region, summer extreme precipitation is also generally intensified and occurs more frequently during the mPWP and LIG, but with large regional differences. The main contributing factors to precipitation change hence vary greatly with sub-regions and periods. Although the modeled variations of extreme precipitation remain hard to be constrained by geological evidence, our results highlight an intensification of extreme precipitation in a warmer world, though the dominating factors (i.e., thermodynamic vs. dynamic) for precipitation change may vary with the external forcing that induces the warmth.

A resilient ice cover over the southernmost Mendeleev Ridge during the late Quaternary

The presence of a late Quaternary ice sheet/ice shelf over the East Siberian Sea has been proposed in several papers. Here, we further document its duration/resilience based on the sedimentary, bulk mineralogical, and geochemical (organic matter content and its stable isotopic composition, U‐Th series) properties of a core raised from the southernmost Mendeleev Ridge. The chronostratigraphy of the studied core was mainly built from the 230Th excess (230Thxs) distribution and decay downcore. At the core‐top, peaking 230Thxs values during the early MIS 3 and mid‐MIS 1 encompassing an MIS 2 hiatus were observed. As documented in several papers, these peaks suggest seasonally open ice conditions over proximal continental shelves. Below, the interval spanning MIS 4 and possibly MIS 5d records major ice‐rafting events illustrated by overall high coarse‐fraction contents. Underlying MIS 5e, down to MIS 11, the sediment depicts relatively low sand (1.7±2.5 dw%), high clay (33.5±4.7 dw%), and very low organic carbon (0.10±0.06 dw%) contents, and low δ13Corg values (−24.3±0.9‰). This section is interpreted as recording fine sediment transport by deep currents and/or meltwater plumes below a resilient ice cover, only interrupted by a few short‐duration events. These events include (i) detrital carbonate pulses assigned to deglacial events along the NW Laurentide Ice Sheet margin (Termination (T) III), and (ii) intervals with some planktonic foraminifer occurrences, likely relating to their advection from open areas of the Arctic Ocean (MIS 5e, 9 and 11). All Terminations, but TII and the early MIS 3, show peaking Mn/Al values linked to the submergence of Arctic shelves under a rising sea level. We conclude that the resilient ice cover, likely an ice shelf, has been present over the southern Mendeleev Ridge during most of the interval after the Mid‐Pleistocene Transition and was favoured by the low summer insolation of the MIS 14 to 10 interval.

BrGDGTs-based temperature and hydrological reconstruction from loess-paleosol deposits in the Eastern European Plain since 200 ka

Knowledge of glacial-interglacial changes in the temperature-humidity configuration of Eastern Europe can provide insights into the regional climate changes in response to ongoing global warming. Here, we present temperature and humidity (soil pH) reconstructions since 200 ka based on records of branched glycerol dialkyl glycerol tetraethers (brGDGTs) for the Strelitsa and Beglitsa loess sections located in the central and southern Eastern European Plain (EEP), respectively. The reconstructed temperatures ranged from 10 to 17 °C in the Strelitsa section and varied between 8 and 19 °C in the Beglitsa section over glacial-interglacial cycles. The reconstructed soil pH in the Strelitsa and Beglitsa sections ranged from 6.1 to 7.8 and from 6.6 to 8.6, respectively, indicating wet conditions during MIS 7 and MIS 1, relatively humid conditions during the interstadials of MIS 6 and MIS 5d–5a, and dry conditions during MIS 5e and the last glacial period. By correlating with climatic records from Eastern Europe, we find that the spatial-temporal distribution of humidity in the central and southern EEP was in line with the meridional shift of the northern westerlies on the orbital time scale. We suggest that the northern westerlies maximum was located over the central and southern EEP, which brought abundant moisture during the interstadials (MIS 6 and MIS 5d–5a) and relatively cool interglacials (MIS 7 and MIS 1), whereas it shifted southward and northward during cold glacial periods and warm MIS 5e, respectively, thereby leading to dry conditions in the central and southern EEP. In this context, the central and southern EEP will become dry in response to the ongoing global warming.

An age scale for new climate records from Sherman Island, West Antarctica

Abstract. Few ice cores from the Amundsen Sea and Bellingshausen Sea sectors of the West Antarctic Ice Sheet (WAIS) extend back in time further than a few hundred years. The WAIS is believed to be susceptible to collapse as a result of anthropogenic climate change and may have at least partially collapsed during the Last Interglacial (LIG) period. Understanding the stability of the WAIS during warm periods such as the LIG and Holocene is important. As part of the WACSWAIN (WArm Climate Stability of the West Antarctic ice sheet in the last INterglacial) project, the British Antarctic Survey's (BAS) Rapid Access Isotope Drill (RAID) was deployed in 2020 on Sherman Island in the Abbot Ice Shelf, West Antarctica. We drilled a 323 m deep borehole, with discrete samples of ice chippings collected that cover the entire depth range of the drilled ice. The samples were analysed for stable water isotope composition and major ion content at BAS from 2020–2022. Using annual layer counting of chemical records, volcanic horizon identification and ice modelling, an age scale for the record of 1724 discrete samples is presented. The Sherman Island ice record extends back to greater than 1240 years, providing the oldest, continuous ice-derived palaeoclimate records in the coastal Amundsen and Bellingshausen Sea sectors to date. We demonstrate the potential for recovery of a complete Holocene climate record from Sherman Island in the future and confidence in the ability of RAID samples to contain sufficiently resolved records for meaningful climatic interpretation.

Can a global mean sea-level rise reduce the Last Interglacial model–data mismatch in East Asia?

The Last Interglacial (LIG), with its many reconstructions and simulations, provides an ideal analog for investigating the future warmer climate. However, there has been a persistent mismatch between simulated and reconstructed LIG climates in East Asia, with simulations generally indicating a colder and drier climate than reconstructions. In this study, utilizing the Norwegian Earth System Model (NorESM1-F), the authors investigated whether incorporating the global mean sea-level rise in LIG simulation experiments can reduce the model–data mismatch. The new experiments reveal a discernible, yet insufficient, warming and wetting effect in East Asia resulting from the sea-level rise. Therefore, the model–data mismatch remains unresolved. Based on these results, the authors explore alternative factors that may contribute to this mismatch, offering insights for future studies.

Environmental conditions across Poland during the Eemian Interglacial reconstructed from vertebrate remains

Knowledge on the Eemian (MIS 5e) fauna of Poland is based on vertebrate remains from 16 open-air localities and 8 cave sites. Considering the short period of time covered by MIS 5e, the amount of data is surprisingly large. There is still an ongoing debate on whether the age of some assemblages is Eemian, latest Saalian or even earliest Weichselian. There are faunal assemblages or stratigraphically isolated finds with some disputable evidence. The full picture of the evolution of the Eemian vertebrate fauna in the present-day territory of Poland is still far from being complete. The finds of various groups of vertebrates (fishes, amphibians, reptiles, birds and mammals) from the Eemian Interglacial of Poland are analysed in terms of their environmental preferences. A number of thermophilic species or forms which preferred temperate climate conditions are known from this period. Among them, Clethrionomys glareolus, Glis glis, Meles meles, Martes martes, Lynx lynx, Felis silvestris, Sus scrofa, Palaeoloxodon antiquus, and Stephanorhinus kirchbergensis indicate a forest environment. The presence of species that preferred more open environments ( Cricetus cricetus, Mammuthus primigenius, Coelodonta antiquitatis, and Equus ferus) is also recorded for the Eemian Interglacial of Poland. Characteristic was the presence of the large broad-toothed and flat-headed Ursus arctos taubachensis, which additionally often outnumbered remains of Ursus spelaeus sensu lato in the contemporary layers. The Eemian vertebrate fauna of Poland consisted of about 150 species (representing 61 genera and 26 families), most of which were recorded earlier from other localities of this age in central and eastern Europe.

Sea ice variability in the North Atlantic subpolar gyre throughout the Last Interglacial

The Last Interglacial period, Marine Isotope Stage 5e (MIS 5e ∼116–128 ka), is thought to have had a warmer, but less stable climate than the present interglacial. One key factor that has the potential to influence the ocean and climate is sea ice, but its presence and extent throughout MIS 5e is poorly constrained. Here we reconstruct the sea surface hydrography and sea ice variability in the Labrador Sea, a region influenced by the subpolar gyre (SPG) and where deep water formation occurs, in order to evaluate the potential of sea ice to drive or amplify ocean variability. We analysed biomarkers (highly branched isoprenoids, HBIs, and sterols), dinoflagellate cyst assemblages and stable oxygen isotopes from the late stages of MIS 6, throughout MIS 5e, into MIS 5d. Our results show that the late glacial MIS 6 was likely characterised by a thick multiyear sea ice cover. During the first phase of MIS 5e, the hydrography was highly variable. The initial 1500 years (128–126.5 ka) were characterised by the presence of a seasonal Marginal Ice Zone (MIZ) accompanied by subsurface warmth. As the sea ice retreated, cool, likely polar-sourced water dominated the surface and subsurface ocean (126.5–124 ka), until an abrupt surge of sea ice marked the final pulse of the remnants of the deglaciation. The second half of MIS 5e (124–116 ka) was characterised by a persistent inflow of warm water, only interrupted by incursions of cold water as summer insolation declined. Seasonal sea ice returned to the Eirik Drift during MIS 5d. We infer that sea ice variability throughout MIS 5e was coupled with the variability of the SPG. Especially the location of a proximal MIZ to the Labrador Sea convection region could have been important for SPG dynamics. In addition, the presence of sea ice at the transitions into and out of MIS 5e could point to its important role in modulating and enhancing the magnitude and coherence of climate signals at major climatic transitions.

PALEOLITHIC SITE SUKHAYA MECHETKA (VOLGOGRAD) IN THE CONTEXT OF STRATIGRAPHY AND PALEOGEOGRAPHY OF THE LOWER VOLGA RIVER AREA

The Sukhaya Mechetka is the most important Middle Paleolithic site in the Eastern Europe. The paper presents the analysis of the section, including its cultural layer, in the context of stratigraphy and paleogeography of the Lower Volga River region. The structure of the section represents 11 main stages of sedimentation and paleogeographic evolution of the site territory, which are closely related to global and regional changes in the climate and the level of the Caspian Sea. The base of the section reflects the stage of a river existence on the territory of the site that flowed into the Volga River estuary, formed by the Early Khazarian transgression of the Caspian Sea at the end of the Middle Pleistocene (MIS 6). A long continental period of evolution under multi-directional climate fluctuations of different amplitudes from the Mikulino interglacial (MIS 5e) till the Late Valdai glacial epoch (MIS 2) is reflected in the middle part of the section. The Late Khazarian and Hyrcanian transgressive basins (MIS 5), as well as the Paleo-Khvalynian stage (MIS 3) of the Caspian Sea did not reach the latitude of Sukhaya Mechetka. The stage of Early Khvalynian transgression (MIS 2, 16 190 ± 200 years ago) during the degradation of Ostashkovo glaciation is expressed in the upper part of the section. Three paleosoils have been found that reflect the warming periods of the MIS 5 stage and are related to its 5e, 5c and 5a sub-stages. The middle paleosoil contains a cultural layer assigned to the Micoquian/KMG community of Northern Eurasia. The climate was moderately warm during the Neanderthal settlement of the territory, steppe landscapes dominated the interfluve, and the forests grew in the balka. The Hyrcanian transgression of the Caspian Sea with an estuary in the Volga River valley predetermined a high erosion basis and the formation of a balka with a wide bottom and gentle banks. A permanent fresh watercourse attracted mammals which were an object of hunting for ancient men. All this, obviously, became a basis for the organization of settlement in the Sukhaya Mechetka balka. Correlation of the section with detailed studied loess-soil sections of the Lower Volga River region makes it possible to determine the age of its cultural horizon in between 97-110 thousand years ago.

Unfavorable environmental conditions for tropical cyclone genesis over the western North Pacific during the Last Interglacial based on PMIP4 simulations

Investigating the variation in tropical cyclone (TC) activity over the western North Pacific (WNP) in past warm periods helps to better understand TC behaviors in a warming future. In this study, the authors analyze the changes in large-scale TC genesis factors and the associated mechanisms over the WNP during the Last Interglacial (LIG), based on multimodel outputs from the Paleoclimate Modelling Intercomparison Project Phase 4. The results show that potential intensity exhibits a general decrease over the WNP during the LIG in the storm season, dominated by a weakened thermodynamic disequilibrium. The moist entropy deficit shows an overall increase over the WNP, arising from the decreased mid-tropospheric moisture and weakened vertical temperature contrast. Vertical wind shear enhances over the central WNP but weakens over the southwestern WNP, which is induced by the changes in the meridional tropospheric temperature gradient and hence high-level zonal winds. The absolute vorticity shows a general decrease over the WNP, partially linked with the decreased SST over the western tropical Pacific. Based on a genesis potential index, the authors suggest a decrease in genesis potential over the WNP during the LIG, indicating unfavorable conditions for TC genesis. The results highlight the important role of Earth's orbit in regulating TC activity, which may shed light on TC behaviors in a warmer climate.

Paleo-pedological record in loess deposits in the south of the East European plain, based on Beglitsa-2017 section study

Loess-paleosol sequences (LPSs) are one of the main components of the natural environment, which traces how the climate has changed in the past. The article discusses changes in the landscape and climatic conditions from the Middle Pleistocene to the present, identified by the results of the LPS of the Beglitsa-2017 section study. We obtained new data on soil cover change in the Late and Middle Pleistocene in the North-Eastern Azov region based on multi-proxy analysis with high-resolution sampling along the section. The first data on the polygenetic origin of the Salyn interglacial paleosol (MIS 5e) profile which developed according to the Gypsic Calcic Chernozems type in the interglacial optimum, was obtained. Still, in the last stage of soil formation, its type changed to the more arid Gypsic Chernozems (Arenic). During MIS 5c and MIS 5a, the paleosols developed in a more arid climate; their modern analogues may be Gypsic Kastanozems and Calcic Gypsisols, respectively. The period of MIS 3 in the study area is marked by severe cryo-arid conditions, which influenced the formation of incipient Calcic Gypsisols. The profiles of the Middle Pleistocene paleosols in the lower part of the LPS of the Beglitsa-2017 section were subject to gleying processes, which formed specific Gleysols or Stagnosols paleosols. The preliminary age of these paleosols corresponds to MIS 13/15 and 8/9. The MIS 7 paleosols are structurally similar to modern Calcic Kastanozems, currently distributed in the dry steppe zone. Reconstruction of the formation of the LPS paleosol cover in the Beglitsa-2017 section made it possible to trace the trend of changes in climatic conditions in the past. Climate aridity decreases in the interval between MIS 5e and MIS 1, and the maximum drought peaks were recorded in MIS 3 paleosols. Earlier, climate aridization intensified from MIS 13/15 and continued until MIS 7/6. The results will complement our understanding of the soil cover changing over time and will expand the reconstruction of climate change throughout the East European Plain.

Last interglacial seasonal hydroclimate in the North Sea–Baltic Sea region

The Last Interglacial (LIG) experienced substantial changes in seasonal insolation compared with the present day, which may have affected the hydrography and water-mass exchange in the North Sea and Baltic Sea region. Here we investigate the effects of solar radiation and greenhouse gas (GHG) forcing on the regional climate by analyzing model simulations of the LIG (127 ka BP), pre-industrial (PI, 1850 CE), and present-day (PD, 1990 CE) climates. We also interpret the reconstructed seasonal bottom water conditions using benthic foraminifera and geochemistry data.Our simulations reveal that during the LIG, the Baltic Sea region (including the Kattegat and the Danish Straits) experienced more saline and colder bottom waters than those in the PD, in agreement with the reconstruction data. This can be attributed to lower GHG levels and enhanced water exchange of cooler, saline North Sea water into the Baltic Sea during the LIG. The thermocline was stronger during the summer months in the LIG, mainly due to the higher sea surface temperature (SST) compared to that of the PD resulting from increased summer insolation.Further, the temperature anomalies (LIG–PD) show significant inverse correlations with the precipitation–minus–evaporation (P–E) at the Baltic Sea entrance. However, the P–E balance appears to have had minimal impact on salinity changes in the North Sea, the Baltic Proper, and the open sea area. Our findings indicate that monthly surface and bottom water salinity anomalies of LIG-PI exhibit strong positive correlations with the North Atlantic Oscillation (NAO) anomalies in the Baltic entrance region. During the LIG, a more positive phase of the NAO index in autumn played a crucial role in wind-driven major inflows and led to more intensive water exchange in the North Sea–Baltic Sea region compared to the late Holocene.