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Postglacial flooding of the Persian Gulf (PG) was important in shaping human history and driving landscape changes in the region. However, there is a paucity of data regarding the postglacial transgression. The position of the PG at the edge of major synoptic systems of the Indian Ocean Summer Monsoon (IOSM) and Mid‐latitude Westerlies (MLW) makes the environment particularly sensitive to Holocene climate shifts. To investigate the timing of the flooding and to detect the impacts of significant climate shifts on the regional environment during the Holocene, a multiproxy study was conducted on three short sediment cores from two deep sites in the PG. Sedimentological, palynological and geochemical analyses were performed on the cores. The results show that inundation of the western part of the PG that started from ca. 11.5 ka bp continued with successive prominent phases of transgression centered on 10.4 and 9.2 ka cal bp, and definitive marine conditions were established around 8.8 ka cal bp. The IOSM was the dominant system in the region until about 9 to ~6.3 ka cal bp. After that time, the intensity of the IOSM declined, as MLW dominated the region after ~6.3 ka cal bp. These climatic shifts induced significant changes in regional vegetation and hydrology, and possibly triggered socio‐cultural transformations. [ABSTRACT FROM AUTHOR]

Investigating past interglacial climatic and environmental changes can enhance our understanding of the natural rates and ranges of climate variability under interglacial boundary conditions. However, comparing past interglacial palaeoclimate records from different regions and archives is often complicated by differing and uncertain chronologies. For instance, the duration of the Last Interglacial in Europe is still controversial as southern European palaeoclimate records suggest a duration of ~16 500–18 000 years, while a length of only ~11 000 years in northern‐central Europe was previously inferred from the analysis of partly annually laminated (varved) palaeolake sediments recovered at Bispingen, northern Germany. To resolve this discrepancy, we here present sediment microfacies, geochemistry and pollen data from a new sediment core from the Bispingen palaeolake sediment succession, covering the entire Last Interglacial (Eemian) and the earliest part of the Last Glacial (Weichselian). In particular, we provide evidence that the duration of the Last Interglacial at Bispingen must have been hitherto underestimated due to the investigation of an incomplete sediment core. Using microscopic varve counting and sedimentation rate estimates for non‐varved sections on the new sediment core, we show that the Eemian in northern‐central Europe probably lasted at least ~15 000 years, about 4000 years longer than previously thought. This new duration estimate is in much better agreement with results from southern European palaeoclimate records, clarifying the enigma of a steep trans‐European vegetation gradient for several millennia at the end of the Last Interglacial. [ABSTRACT FROM AUTHOR]

Reconstructions of aeolian dust flux to West African margin sediments can be used to explore changing atmospheric circulation and hydroclimate over North Africa on millennial to orbital timescales. Here, we extend West African margin dust flux records back to 37 ka in a transect of sites from 19° to 27°N, and back to 67 ka at Ocean Drilling Program (ODP) Hole 658C, in order to explore the interplay of orbital and high‐latitude forcings on North African climate and make quantitative estimates of dust flux during the core of the Last Glacial Maximum (LGM). The ODP 658C record shows a Green Sahara interval from 60 to 50 ka during a time of high Northern Hemisphere summer insolation, with dust fluxes similar to levels during the early Holocene African Humid Period, and an abrupt peak in flux during Heinrich event 5a (H5a). Dust fluxes increase from 50 to 35 ka while the high‐latitude Northern Hemisphere cools, with peaks in dust flux associated with North Atlantic cool events. From 35 ka through the LGM dust deposition decreases in all cores, and little response is observed to low‐latitude insolation changes. Dust fluxes at sites from 21° to 27°N were near late Holocene levels during the LGM time slice, suggesting a more muted LGM response than observed from mid‐latitude dust sources. Records along the northwest African margin suggest important differences in wind responses during different stadials, with maximum dust flux anomalies centered south of 20°N during H1 and north of 20°N during the Younger Dryas. Plain Language Summary: Dust that is picked up by winds over North Africa and blown out into the Atlantic Ocean can tell us about climate change in the past, particularly about variations in wind strength and location, and how wet the continent was. This study uses seafloor sediments from four sites offshore of West Africa to reconstruct how much dust was blown out from North Africa over the last 67,000 years. The records show that the climate of North Africa is controlled by two major processes: changes to incoming energy from the sun on timescales of thousands of years, and the extent of cold conditions in the high latitudes of the North Atlantic region on timescales of hundreds of years. We find a time from 60,000 to 50,000 years ago of low dust export (weak winds and a wet continent) when incoming energy from the sun was high, with dust levels similar to those during the Green Sahara interval that occurred 11,000 to 5,000 years ago. This time of low dust export was interrupted around 54,500 years ago by a brief interval of extremely high dust export (strong winds and a dry continent) during a North Atlantic cold interval called Heinrich event 5a. Key Points: Coherent dust flux changes along the NW African margin and in the central North Atlantic over the last 67 kaAbrupt dust flux variations on millennial timescales similar to N Atlantic stadials related to high‐latitude forcing of African climateGreen Sahara interval (60–50 ka) recorded by low dust fluxes to ODP 658C showing an orbitally forced strengthening of monsoon during MIS 3 [ABSTRACT FROM AUTHOR]

The sediment profile from Lake Gościąż in central Poland comprises a continuous, seasonally resolved and exceptionally well‐preserved archive of the Younger Dryas (YD) climate variation. This provides a unique opportunity for detailed investigation of lake system responses during periods of rapid climate cooling (YD onset) and warming (YD termination). The new varve record of Lake Gościąż presented here spans 1662 years from the late Allerød (AL) to the early Preboreal (PB). Microscopic varve counting provides an independent chronology with a YD duration of 1149+14/–22 years, which confirms previous results of 1140±40 years. We link stable oxygen isotopes and chironomid‐based air temperature reconstructions with the response of various geochemical and varve microfacies proxies especially focusing on the onset and termination of the YD. Cooling at the YD onset lasted ~180 years, which is about a century longer than the terminal warming that was completed in ~70 years. During the AL/YD transition, environmental proxy data lagged the onset of cooling by ~90 years and revealed an increase of lake productivity and internal lake re‐suspension as well as slightly higher detrital sediment input. In contrast, rapid warming and environmental changes during the YD/PB transition occurred simultaneously. However, initial changes such as declining diatom deposition and detrital input occurred already a few centuries before the rapid warming at the YD/PB transition. These environmental changes likely reflect a gradual increase in summer air temperatures already during the YD. Our data indicate complex and differing environmental responses to the major climate changes related to the YD, which involve different proxy sensitivities and threshold processes. [ABSTRACT FROM AUTHOR]

Asian mineral dust has been studied extensively for its role in affecting regional‐to global‐scale climate and for its deposits, which enable reconstructing Asian atmospheric circulation in the past. However, the timing and origin of the dust deposits remain debated. Numerous loess records have been reported across the Asian continent with ages varying from the Miocene to the Eocene and linked to various mechanisms including global cooling, Tibetan Plateau uplift and retreat of the inland proto‐Paratethys Sea. Here, we study the Eocene terrestrial mudrocks of the Xining Basin in central China and use nonparametric end‐member analysis of grain‐size distributions to identify a loess‐like dust component appearing in the record at 40 Ma. This is coeval with the onset of high‐latitude orbital cycles and a shift to predominant steppe‐desert vegetation as recognized by previous studies in the same record. Furthermore, we derive wind directions from eolian dune deposits which suggest northwesterly winds, similar to the modern‐day winter monsoon which is driven by a high pressure system developing over Siberia. We propose that the observed shifts at 40 Ma reflect the onset of the Siberian High interacting with westerly derived moisture at obliquity timescales and promoting dust storms and aridification in central China. The timing suggests that the onset may have been triggered by increased continentality due to the retreating proto‐Paratethys Sea. Key Points: The onset of Asian dust is identified at 40 Ma within a longer continuous recordShifts in the dust, cyclostratigraphy and pollen suggest the Siberian High at 40 MaThe coeval proto‐Paratethys Sea retreat triggered the onset of the Siberian High [ABSTRACT FROM AUTHOR]

ABSTRACT We present an early Holocene record from Lake Meerfelder Maar in Germany for in-depth interpretation of depositional changes in annually laminated lake sediments as proxies for climatic and local environmental changes. We characterized the compositional changes in the sediment record using Ward's clustering analyses of the micro X-ray fluorescence core scanning data and linked these to microfacies descriptions. The down-core distribution of the clusters allowed us to define boundaries that represent variations of a comprehensive element assemblage occurring at 11 555, 11 230, 10 650, 10 515 and 9670 varve a BP. Our main results show that during the Early Holocene the long-term vegetation reorganization and evolution of the lake's catchment played a predominant role for sediment deposition. Abrupt shifts occurred at the Younger Dryas/Holocene and the Preboreal/Boreal biostratigraphical boundaries. We do not observe clear signals corresponding to known short-term climatic oscillations described in the North Atlantic region such as the Preboreal Oscillation. A unique and intriguing episode in the history of the lake of predominantly organic deposition and very low amounts of allochthonous sediments occurred between 10 515 and 9670 varve a BP and is related to hydrological thresholds. [ABSTRACT FROM AUTHOR]

ABSTRACT The Baumkirchen clay pit near Innsbruck, western Austria, is a well-known site in Alpine Quaternary stratigraphy. Lacustrine sediments from the last glacial cycle from within the Alps provide a unique opportunity to investigate the regional palaeoclimate. Recent drilling has extended the known sequence to a total length of at least 250 m consisting of almost entirely well-laminated clayey silt. Luminescence dating identified two lake sequences, separated by a hiatus of ca. 7000-15 000 years. Lake phase 1 spans the period ca. 77-55 ka, i.e. from about Marine Isotope Stage (MIS) 5/4 to the MIS 4/3 transition. Lake phase 2 extends from mid- to late MIS 3 between ca. 45 and 33 ka. Down-core X-ray fluorescence core scanning confirmed the presence of the lake phases in the sediment composition, suggesting different sediment sources and/or transport mechanisms during these two intervals. A unique section of exotic, angular, silt matrix-supported gravel at the top of lake phase 1 is interpreted as ice-rafted debris. Luminescence dating constrains this layer to ca. 55 ka, thus providing the first evidence of a late MIS 4 or early MIS 3 ice advance confined to the interior of the Eastern Alps. A conceptual model of the sedimentary history of the valley is presented. [ABSTRACT FROM AUTHOR]

ABSTRACT We report the first findings of coexisting early Holocene Hässeldalen and Askja-S cryptotephras in a varved sediment record in Lake Czechowskie (Poland). A time span of 152 +11/−8 varve years between the two tephras has been revealed by differential dating through varve counting. This is in agreement within the uncertainties with calculations from radiocarbon-based age models from the non-varved Hässeldala port record in southern Sweden, but shorter than assumed from the non-varved lake record on the Faroe Islands. We discuss possible reasons for the observed differences in duration between the two tephras and provide a revised absolute age for the Askja-S tephra of 11 228 ± 226 cal a BP based on anchoring our floating varve chronology to the absolute timescale by using the Hässeldalen Tephra as dated in the Hässeldala port sediments (11 380 ± 216 cal a BP). This age agrees with radiocarbon age models with larger uncertainty ranges, but is slightly older than radiocarbon-based age models with narrow uncertainty bands and is even 200-300 years older than the age reported from the Faroe Islands record. In addition to these chronological issues we discuss the possible response of the Czechowskie sediment record to the Preboreal climate oscillation. [ABSTRACT FROM AUTHOR]

ABSTRACT A new sea-level record derived from coastal deposits of the South Vietnam shelf covers the deglacial sea-level history between 13.0 and 9.0 ka BP. This record reveals a relatively constant rate of sea-level rise and matches well with model results based on the RSES-ANU global ice-sheet model. However, the sea-level observations reveal a significant discrepancy with model results based on the ICE-5G global ice-sheet model, which further questions the existence of Meltwater Pulse 1B The incised-valley deposits of the South Vietnam shelf also complete the deglacial coastal evolution of southern Vietnam. The regional sea-level records of the South Vietnam shelf, the Mekong Delta and the Cambodian lowlands reveal an offset of about 18 m between 9.0 and 8.2 ka BP. The shoreline retreat of more than 200 km related to this offset was mainly caused by the differential hydro-isostatic adjustment between the South Vietnam shelf and the Cambodian lowlands. However, the GIA-model results cannot fully explain this fast relative sea-level rise due to the topographic changes and, possibly, alternative melt-water sources not accounted for in the current models. [ABSTRACT FROM AUTHOR]

Reading the sediment record in terms of past climates is challenging since linking climate change to the associated responses of sedimentary systems is not always straightforward. Here we analyze the erosional response of landscapes on the Tibetan Plateau to interglacial climate forcing. Using the theory of dynamical systems on Holocene time series of geochemical proxies, we derive a sedimentary response model that accurately simulates observed proxy variation in three lake records. The model suggests that millennial variations in sediment composition reflect a self‐organization of landscapes in response to abrupt climate change between 11.6 and 11.9 ka BP. The self‐organization is characterized by oscillations in sediment supply emerging from a feedback between physical and chemical erosion processes, with estimated response times between 3,000 to 18,000 years depending on catchment topography. The implications of our findings emphasize the need for landscape response models to decipher the paleoclimatic code in continental sediment records. Plain Language Summary: Lake sediments are an important source of information on past climates. Reading the information is not always straightforward. Complex interactions in landscapes can affect the transmission of climatic signals to the sediment record. However, the exact nature of such complex interactions remains unknown. This study compares sediment deposits of three lakes on the Tibetan Plateau. The deposits are continuous records of landscape responses to climate change during the last 12,000 years. We identified a mathematical model that accurately simulates changes in sediment composition at all sites. The model simulations suggest that an abrupt warming at the end of the last glacial period destabilized the landscapes. This caused fluctuations in the transport of sediments, which persisted for several thousand years. Our findings present evidence for a long‐lasting impact of abrupt climate change on fundamental Earth surface processes. Key Points: We analyzed the propagation of climatic signals to Holocene sediment records of three well‐studied Tibetan lakes in a dynamical system frameworkHolocene variation in geochemical proxies mainly reflect site‐specific landscape responses to abrupt climate changeOur results indicate a feedback between physical and chemical erosion processes on interglacial timescale [ABSTRACT FROM AUTHOR]