A correlation of stratigraphic subdivisions of the late Middle Pleistocene (MIS 12-6) in central Europe is extremely difficult, because of abundant hiatuses. Therefore, the site Rechitsa in western ...Belarus is extremely important for a regional stratigraphy, because of its well documented sediments of the Alexandrian Interglacial (Holsteinian; MIS 11) and a crucial palaeoclimate and palaeoenvironmental record of the Middle Pleistocene. The sequence starts with proglacial delta deposits formed at the termination of the Berezinian Glaciation (Elsterian; MIS 12), overlain by organic deposits of the Alexandrian Interglacial (Holsteinian; MIS 11) and the early glacial cooling of the Pripyatian Glaciation (Saalian). The hiatuses in MIS 10, 9 and 7 are interrupted by occasional occurrence of a periglacial lake, accompanied with open vegetation communities in MIS 8, characteristic by alternate temperate and cold episodes with significant climate-induced environmental transformations with extremely cold and dry conditions recorded by huge frost wedges with primary infilling. Extremely severe climatic conditions of MIS 6 favoured development of huge frost wedges with primary infilling, overlain by sediments of a periglacial lake. The Rechitsa section was overbuilt by glaciofluvial and aeolian deposits during the Pripyatian Glaciation (Saalian). The recorded huge hiatuses in MIS 10, 9 and 7 are common in central Europe represent presumably arid conditions and lack of deposition. The sedimentary sequence at the site Rechitsa is an important link of central and eastern European stratigraphic subdivisions of the Middle Pleistocene.
The iconic climate archive of Tenaghi Philippon (TP), NE Greece, allows the study of short-term palaeoclimatic and environmental change throughout the past 1.3 Ma. To provide high-quality age control ...for detailed palaeoclimate reconstructions based on the TP archive, (crypto)tephra studies of a peat core ‘TP-2005’ have been carried out for the 0–130 ka interval. The results show that the TP basin is ideally positioned to receive tephra fall from both the Italian and Aegean Arc volcanic provinces. Two visible tephra layers, the Santorini Cape Riva/Y-2 (c. 22 ka) and the Campanian Ignimbrite (CI)/Y-5 (c. 39.8 ka) tephras, and six primary cryptotephra layers, namely the early Holocene E1 tephra from the Aeolian Islands (c. 8.3 ka), the Campanian Y-3 (c. 29 ka) and X-6 tephras (c. 109.5 ka), as well as counterpart tephras TM-18-1d (c. 40.4 ka), TM-23-11 (c. 92.4 ka) and TM-33-1a (c. 116.7 ka) from the Lago Grande di Monticchio sequence (southern Italy), were identified along with repeatedly redeposited Y-2 and CI tephra material. Bayesian modelling of the ages of seven of the primary tephra layers, 60 radiocarbon measurements and 20 palynological control points have been applied to markedly improve the chronology of the TP archive. This revised chronology constrains the age of tephra TM-18-1d to 40.90–41.66 cal ka BP (95.4% range). Several tephra layers identified in the TP record form important isochrons for correlating this archive with other terrestrial (e.g., Lago Grande di Monticchio, Sulmona Basin and Lake Ohrid) and marine (e.g., Adriatic Sea core PRAD 1-2 and Aegean Sea core LC21) palaeoclimate records in the Mediterranean region.
•8 (crypto)tephras are identified in the MIS 1–5 peat record of Tenaghi Philippon.•Tephras have Italian and Aegean Arc provenances.•Most Italian tephras, including X-6, were found in their most distal sites.•The MIS 1–5 chronology of TP was improved by Bayesian modelling.
The Demerara Plateau is a marginal plateau which forms a bathymetric relief on the sea floor. Here, contourite deposits have been studied in detail, following the recent discovery of contourite ...sequences likely related to the bottom currents and linked both to contour current and peculiar sea-floor morphology. A chronostratigraphic framework, based on δ18O relative variations and palaeomagnetic events in sediment cores allows correlating sediment processes to current intensity changes and major climate phases (glacial or interglacial). The studied sediments are enriched in glauconitic grains. In addition, the glauconite mineralogical maturity can easily correlate to low sedimentation rate and slightly energetic bottom currents on the seafloor. Based on these data and using the glauconitic authigenic mineral as proxy for inferring the degree of winnowing at the sediment-water interface, we might put forward the hypothesis that the intensity of NADW is higher during the glacial stages and lower during interglacial periods.
•A contourite depositional system is present on the Demerara Plateau.•The winnowing effect induced by bottom current allows formation of authigenic mineral.•The glauconitic content and maturity of glauconitic grains are indicator of the current intensity.
The mid-Late Pleistocene and Holocene aeolianites of the Tamala Limestone on the northern Swan Coastal Plain in southwestern Western Australia consist of six members that show cyclic deposition of ...coastal aeolianite, overlain by calcrete/microbialite, karstified surface and palaeosol. Field work, combined with mineralogical, chemical, stable isotope analysis and uranium-thorium (U/Th) and optically stimulated luminescence (OSL) dating, provides an insight into the repetitive glacial and interglacial climatic periods over the past 500kyr. Deposition of the carbonate aeolianites occurred during interglacial episodes (marine isotope stage (MIS) 1, 5, 7, 9, 11, and possibly 13), due to migration of coastal dunes under the influence of strong southerly to southwesterly winds. Rainfall was insufficient to support vegetation cover on the dunes, and so was probably limited or seasonal. The transition from interglacial to glacial climates was characterised by higher effective rainfall, accompanied by aeolianite dissolution and karstification. During the colder climates and less effective rainfall of the glacial periods, there was no carbonate sand deposition; instead laminated microbialite and/or laminar calcrete formed, followed by palaeosol formation. The oxygen isotope composition of the microbialites indicates average temperatures during glacial periods ~4°C −8°C lower than today, and δ13C values demonstrate a higher proportion of C4 plants and therefore a drier or more seasonal climate. Data from individual members of the Tamala Limestone show that the wettest interglacial period was MIS 5, when extensive karstification and pinnacle development occurred, and rainfall was probably higher than at any other time in the past 500kyr. Of the glacial periods, MIS 10 was relatively wet or less seasonal, whereas MIS 8 and the Last Glacial Maximum (LGM) were relatively dry and windy. The low rainfall during the peak of the glacial periods was probably intensified by colder water offshore, due to weakening of the Leeuwin Current and its replacement by the cold, north-flowing West Australian Current.
•On the Swan Coastal Plain aeolianites were mostly deposited during interglacials.•Glacial periods were drier and colder (by 4–8°C) with more C4 plants.•High rainfall during interglacial MIS 5e caused intense karstification.•Microbialites and/or calcrete were deposited during glacial episodes.•Coastal aeolianites can be very valuable for palaeoclimate interpretation.
The lowest section of the Upper Dniester River Valley (DRV), located between the uplands of Opillia and Eastern Subcarpathians, was a separate and specific Pleistocene geoecosystem, interesting for ...the hunter-gatherer communities. This is evidenced by three main (Yezupil, Mariampil and Halych), and a dozen or so additional Palaeolithic open-air sites. They occur as cultural layers within the loess-palaeosol sequences (LPSs) and represent semi-permanent settlement (except for the periods with the maximum intensity of the loess sedimentation); the oldest occur in the Eemian palaeosol. All sites are located on both sides of the river. In the past, the DRV was characterized by local environmental diversity changing with time. In consequence, it has very individual features, so the analysis of environmental changes is a local case study. In order to obtain information about the changes of climate and environment, the multi-proxy analyses were carried out. Chronology was based on the luminescence and radiocarbon dating. The diversity of habitats was local. Its degree was changing with time: it was minimal in the periods with extreme climatic conditions, such as the climate optimum and pessimum, and clearly greater in the climatically intermediate periods with fluctuations. Based on the materials indicating the mesoclimate and local vegetation diversity during the human occupation episodes as well as the location of the Palaeolithic sites, we found that generally the possibilities of choosing a warmer or sheltered place for a camp were not significant for hunters representing different cultures of different ages. Palaeolithic groups very often occupied the same places in the DRV. The camps had a hunting function, the choice of places was dictated primarily by the need to find a good place to observe game animals and to organize hunting – first of all – in the mouth sections of the tributaries of the Dniester River, regardless of the situation of localities relative to riverplains. The settlement attractiveness of such places was essentially timeless.
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Understanding the history of continental ice-sheet growth on North America, and in particular that of the Laurentide Ice Sheet (LIS), is important for palaeoclimate and sea-level reconstructions. ...Information on ice-sheet extent pre-dating the Last Glacial Maximum (LGM) is heavily reliant, though, on the outputs of numerical models underpinned by scant geological data. Important aspects of LIS history that remain unresolved include the timing of its collapse during Termination 2, the first time that it expanded significantly during the Last Glacial Cycle, and whether its volume was significantly reduced during marine isotope stage (MIS) 3. To address these issues and more, we present authigenic iron-manganese (Fe–Mn) oxyhydroxide-derived high-resolution records of Pb isotope data and associated rare earth element profiles for samples spanning the past ∼130 kyr from northwest North Atlantic Labrador Sea, IODP Site U1302/3. We use these new data to track chemical weathering intensity and solute flux to the Labrador Sea associated with LIS extent on the adjacent highly radiogenic (high Pb isotope composition) North American Superior Province (SP) craton since the Penultimate Glacial Maximum (PGM). Our new records show that relatively high (radiogenic) values characterise warm marine isotope stages (MIS) 5, 3 and 1 and the lowest (most unradiogenic) values occurred during cold stages MIS 6, 4 and 2. The radiogenic Pb isotope excursion associated with Termination 2 is short-lived relative to the one documented for Termination 1, suggesting that LIS retreat during the PGM was relatively fast compared to the LGM and that its collapse during the last interglacial occurred ∼125 ka. Highly radiogenic inputs to the Labrador Sea during MIS 5d-a, ∼116–71 ka, most likely reflect a spin-up in Labrador Current vigour, incipient glaciation and renewed glacial erosion of high grounds of the eastern SP craton by localised wet-based ice-caps. A large decrease in Pb isotope values towards unradiogenic LGM-like compositions between ∼75–65 ka across the MIS 5/4 transition likely reflects a slow-down in Labrador Current vigour, an increase in subaerial deposition of aeolian dust and a significant advance of the LIS across Hudson Bay caused a strong reduction or even abandonment of Pb sourcing from the SP. The relatively radiogenic Pb isotope composition of bottom-waters bathing our study site during MIS 3, 57–29 ka, is unlikely to support a recently proposed major reduction in LIS extent for this time. Instead, we argue these values are better explained by southern Greenland Ice Sheet retreat, increased chemical weathering of the Ketelidian Mobile Belt and subsequent Pb runoff from Greenland.
•We present LGC record of the Pb isotope composition Labrador Sea seawater.•These data can be used to track Laurentide Ice Sheet extent over Hudson Bay.•LIS retreat during the PGM was relatively fast compared to the LGM•The LIS first advanced significantly over Hudson Bay during MIS 4.•Our record does not support significant LIS retreat during MIS 3.
Diatom abundance and species distribution present a subtle tool for the reconstruction of the orbital and millennial-centennial climate and environmental changes in the southwestern Bering Sea during ...the last 172 ka, in addition to productivity proxies (chlorine, color b*, and Ca/Ti ratio), magnetic susceptibility, and biomarker proxies derived earlier and in this paper from the sediment core SO201-2-85KL recovered at the middle Shirshov Ridge (MSR). Available data indicate that the MSR area undergoes a significant seasonal sea ice influence during cold MISs 6.5–2. During the colder MIS 2, a main area of ice discharge extended southward of the MSR, likely outside of the sea, while over the coldest MIS 6.2, the MSR area was free from ice due to the shifting of the Aleutian Low to the eastern Siberian coast and the northward transfer of the warm and wet air of storm tracks into the western Bering Sea. During the warm MIS 5.5, the sea ice influence at the MSR area was negligible, nearly the same as it was over the Holocene, and it began to increase after event 26 (120.5 ka). The millennial scale variability of diatom abundance and its species distribution were triggered by Greenland Interstadials accompanied by productivity changes. The diatom species distribution showed complicated pattern of variability of the MSR environment, consistent with the millennial-centennial changes of the Greenland air temperature over the Dansgaard -Oeschger cycles. It confirms the rapid mechanisms of atmospheric teleconnection between these remote regions on the millennial-centennial time scale.
•Full sequences of the Bering Sea/Greenland/Chinese Interstadials during MIS 1–6.•During MIS 6.2 studied area was free of sea ice due to westward shift of Aleutian Low.•similarity of the Bering Sea and Greenland millennial-centennial environmental changes.
This study examined the temporal patterns of paleo-earthquake recurrences on the Korean Peninsula, situated near the Eurasian Plate boundary, by using electron spin resonance (ESR) dating to ...ascertain the ages at which fault gouge patches were reactivated. The findings reveal that the paleo-earthquakes in each of the fault zones (Keumwang, southern part of Wangsukcheon, Yangsan, and Ulsan) display quasiperiodic patterns. The observed patterns align with a time-dependent earthquake recurrence model. A periodicity of approximately 100 kyr could represent a regional baseline for fault activity. Over the past 650 kyr, the periodicity of paleo-earthquakes has coincided with the interglacial periods of marine isotope stages (MIS) 15, 13, 11, 9, and 7. On the Korean Peninsula, it is hypothesized that long-term differential stress changes, resulting from sea-level rises in the Pacific Ocean, have played a significant role in driving Quaternary fault activities during these interglacial stages. Consequently, this study suggests that the ongoing global warming trend could potentially increase the earthquake frequency on the Korean Peninsula.
•The paleo-earthquakes within each of the fault zones (Keumwang, Wangsukcheon, Yangsan, and Ulsan) on the Korean Peninsula exhibit quasiperiodic patterns, having a periodicity of approximately 100 kyr.•The periodicity of paleo-earthquakes on the Korean Peninsula coincides with the interglacial periods associated with marine isotope stages 15, 13, 11, 9, and 7.•Long-term changes in differential stress, induced by sea-level rise, have played a significant role in triggering Quaternary fault activity on the Korean Peninsula.
In northern China, the history of desert migration provides a good measure of the East-Asian summer monsoon variations, since the desert margin environment is very sensitive to changes in summer ...monsoon rainfall. Desert margin migration can be well documented in the downwind loess deposits, since the grain size of Chinese loess is principally controlled by source-to-sink distance and hence the loess grain size is an effective proxy for reconstructing the history of the East-Asian summer monsoon. In order to investigate the pattern and migration of the summer monsoon rainfall belt over northern China during the past two glacial–interglacial cycles, contour maps of loess grain size were constructed for MIS 2, 3, 4, 5, 6 and 7. All the grain-size isolines show a near north–south gradient for both glacials and interglacials, indicating a dominant dust source region in north and an approximately north–south dust transport pathway for dust deposits in the main body of the Loess Plateau, at least for the past two glacial–interglacial cycles. The reconstructed southeast desert margin for MIS 2, 3, 4, 5, 6 and 7 roughly parallels the present isohyets, implying that the pattern of the East-Asian summer monsoon rainfall belt during the past two glacial–interglacial cycles is similar to the present, i.e. a northeast–southwest trend for the isohyets of the summer monsoon, despite the glacial–interglacial cycles. Using the grain-size isolines of MIS 2 as a reference, we derive a northerly desert retreat of ∼
160 km, ∼
19 km, ∼
225 km and ∼
223 km for MIS 3, 4, 5 and 7, respectively, and a southerly desert advance of ∼
29 km for MIS 6, that could be preliminarily regarded as the relative migration distance for the East-Asian summer monsoon rainfall belt. In addition, the inferred climate conditions in MIS 3 are cool and humid in northern China, while the driest and coldest interval of the last two glacial periods occurs in MIS 6.
The loess-paleosol sequences in the Chinese Loess Plateau (CLP) are an important terrestrial paleoclimate record. However, quantitative understanding of the response of paleosol development to ...various climate and environmental factors remains poor. Based on simulations with combined soil-climate models (SoilGen2-LOVECLIM1.3), this study investigates the sensitivity of paleosol development to different soil forming factors as well as the influence of ice sheets and astronomical forcing during the interglacials of the past 500 ka. Sensitivity analyses show that precipitation, dust addition and evapotranspiration are the dominant factors controlling the interglacial paleosol formation, but their relative importance varies between intergalcials and for different soil properties such as calcite and clay contents. Our results show that the simulated S1, S2, S3, S5-1 paleosols, which correspond to MIS 5, 7, 9 and 13 respectively, exhibit strong relationship with precession through its control on precipitation, whereas the precession signal is weak in the simulated S4 paleosol, in line with the weak precession variation during MIS 11. The results also show variable length of lags between different soil properties and precession and also in different interglacials. The lag between the simulated calcite and precession is shorter than that of clay. Moreover, clay content also shows strong relation with temperature during MIS 5 and MIS 13. Large ice sheets in the early and late phases of the interglacials have substantial impact on both temperature and precipitation in the CLP and thus on carbonate leaching and clay migration. Therefore, the simulated paleosols result mainly from the joint effect of precession and ice sheets via their control on local climate, and they show qualitative agreement with observations.
•Precipitation, dust and evaporation are the major controlling factors on paleosols in the CLP.•Their relative importance varies between soil properties and between interglacials.•Paleosols record a lagged precession-driven variability. The length of lag depends on soil properties and on interglacials.•Ice sheets could have strong effect on carbonate leaching and clay migration in the CLP.
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