scholarly journals Pleistocene climate characteristics in the most continental part of the northern hemisphere: insights from cryolithological features of the Batagay mega thaw slump in the Siberian Yana Highlands

2016 ◽  
Author(s):  
Kseniia Ashastina ◽  
Lutz Schirrmeister ◽  
Margret Fuchs ◽  
Frank Kienast
Keyword(s):  
Northern Hemisphere ◽  
Late Pleistocene ◽  
Fine Sand ◽  
Detailed Comparison ◽  
Ground Temperature ◽  
Middle Pleistocene ◽  
Climate Conditions ◽  
The Holocene ◽  
Cold Stage ◽  
Ice Complex

Abstract. Syngenetic permafrost deposits formed extensively on and around the arising Beringian subcontinent during the Late Pleistocene sea level low stands. Syngenetic deposition implies that all material, both mineral and organic, gets frozen parallel to sedimentation and remains frozen until degradation of the permafrost. Permafrost is therefore a unique archive of late Pleistocene paleoclimates. Most studied permafrost outcrops are situated in the coastal lowlands of NE Siberia and are thus under certain influence of today’s rather maritime climate. Permafrost sections more inland are in contrast scarcely available. Here we describe the cryolithological and geochronological characteristics of a permafrost sequence near Batagay in the Siberian Yana Highlands, the interior of the Republic Sakha (Yakutia), Russia. The recently formed Batagay mega thaw slump exposes permafrost deposits to a depth of up to 80 m and gives insight into a sought climate record close-by the Pole of Cold – the place with the most severe continental climate of the Northern Hemisphere. We provide a detailed stratigraphic description of this profile and present results of cryolithological and geochemical analyses to deduce the genesis of the permafrost sequence, which comprised, according to our observations and sedimentological results, five lithological units. Geochronological dating (OSL and 14C ages) and stratigraphic implications delivered a temporal frame from the Middle Pleistocene to the Holocene for our sedimentological interpretations and also revealed interruptions in the deposition of the sequence. The sequence of lithological units indicates a succession of several distinct climate phases: a middle Pleistocene Ice Complex indicates cold stage climate conditions resulting in a mean annual ground temperature at least 8 °C lower than today; then, ice wedge growth stopped due to highly increased sedimentation rates and eventually a rise of temperature; full interglacial climate conditions existed during accumulation of an organic-rich layer - plant macrofossils reflected open forest vegetation existing under dry conditions during MIS 5e, the late Pleistocene YIC (MIS 4-2) proves again severe cold-stage climate conditions with a mean annual ground temperature 8 to 10 °C lower than today. In the Holocene cover, no alas deposits indicating thermokarst processes, were detected. The main focus of our studies was material from the late Pleistocene Yedoma Ice Complex. The permafrost section was sampled over a depth of 60 m and analyzed for a range of sedimentological properties. The sequence is composed mainly of fine-sand with percentages from 40 % to 70 % varying between as well as within the units. Total organic carbon changes from 0.1 wt % to 4.8 wt %, magnetic susceptibility values are within the range of 13.7–30 SL. A detailed comparison of the permafrost deposits exposed in the Batagay thaw slump with well-studied permafrost sequences, both coastal and inland, is made to highlight common features and differences in their formation processes and palaeoclimatic histories. Despite stratigraphical similarities to coastal outcrops, the Batagay sequence differs in some characteristics from them. Fluvial and lacustrine influence is common for certain depositional periods in the majority of permafrost exposures but have to be excluded for the Batagay sequence. We interpret the characteristics of Yedoma deposits at this location as a result of various involved climatically induced processes that are partly seasonally controlled: nival deposition might have been dominant during winter time, whereas proluvial and aeolian deposition could have prevailed during the snowmelt period and the dry summer season.

scholarly journals Palaeoclimate characteristics in interior Siberia of MIS 6–2: first insights from the Batagay permafrost mega-thaw slump in the Yana Highlands

2017 ◽  
Vol 13 (7) ◽  
pp. 795-818 ◽  
Author(s):  
Kseniia Ashastina ◽  
Lutz Schirrmeister ◽  
Margret Fuchs ◽  
Frank Kienast
Keyword(s):  
Late Pleistocene ◽  
Detailed Comparison ◽  
Plant Macrofossils ◽  
Middle Pleistocene ◽  
Climate Conditions ◽  
Cold Stage ◽  
Dry Conditions ◽  
Winter Time ◽  
Geochronological Dating ◽  
Ice Complex

Abstract. Syngenetic permafrost deposits formed extensively on and around the arising Beringian subcontinent during the Late Pleistocene sea level lowstands. Syngenetic deposition implies that all material, both mineral and organic, freezes parallel to sedimentation and remains frozen until degradation of the permafrost. Permafrost is therefore a unique archive of Late Pleistocene palaeoclimate. Most studied permafrost outcrops are situated in the coastal lowlands of northeastern Siberia; inland sections are, however, scarcely available. Here, we describe the stratigraphical, cryolithological, and geochronological characteristics of a permafrost sequence near Batagay in the Siberian Yana Highlands, the interior of the Sakha Republic (Yakutia), Russia, with focus on the Late Pleistocene Yedoma ice complex (YIC). The recently formed Batagay mega-thaw slump exposes permafrost deposits to a depth of up to 80 m and gives insight into a climate record close to Verkhoyansk, which has the most severe continental climate in the Northern Hemisphere. Geochronological dating (optically stimulated luminescence, OSL, and 14C ages) and stratigraphic implications delivered a temporal frame from the Middle Pleistocene to the Holocene for our sedimentological interpretations and also revealed interruptions in the deposition. The sequence of lithological units indicates a succession of several distinct climate phases: a Middle Pleistocene ice complex indicates cold stage climate. Then, ice wedge growth stopped due to highly increased sedimentation rates and eventually a rise in temperature. Full interglacial climate conditions existed during accumulation of an organic-rich layer – plant macrofossils reflected open forest vegetation existing under dry conditions during Marine Isotope Stage (MIS) 5e. The Late Pleistocene YIC (MIS 4–MIS 2) suggests severe cold-stage climate conditions. No alas deposits, potentially indicating thermokarst processes, were detected at the site. A detailed comparison of the permafrost deposits exposed in the Batagay thaw slump with well-studied permafrost sequences, both coastal and inland, is made to highlight common features and differences in their formation processes and palaeoclimatic histories. Fluvial and lacustrine influence is temporarily common in the majority of permafrost exposures, but has to be excluded for the Batagay sequence. We interpret the characteristics of permafrost deposits at this location as a result of various climatically induced processes that are partly seasonally controlled. Nival deposition might have been dominant during winter time, whereas proluvial and aeolian deposition could have prevailed during the snowmelt period and the dry summer season.

scholarly journals Paleocryogenic processes in the Volyn` Upland

2018 ◽  
Vol 26 (1) ◽  
pp. 3-16
Author(s):  
О. S. Bonchkovskyi
Keyword(s):  
Late Pleistocene ◽  
Loess Soil ◽  
Early Pleistocene ◽  
Middle Pleistocene ◽  
Climate Conditions ◽  
Cold Stage ◽  
Short Period ◽  
Different Types ◽  
Cryogenic Processes

On the basis of the study of 13 Quaternary loess-soil sections in the Volyn’ Upland, cryogenic horizons of different ranges have been recorded and positioned within the Quaternaty stratigrpahical framework of Ukraine. A short-period cyclicity in development of cryogenic processes has been revealed. Time units of formation of cryostuctures − ‘cryostages’ – have been ranged into four categories in correspondence with landscape-climate conditions of their formation and their relations with the units of paleogeogrpahic framework of Ukraine. The differences in cryostructures and cryodeformations for each category of cryostages are shown. A variety of cryostructures and their sizes became larger from the beginning to the end of the Pleistocene that reflects an increase in the climate harshness. Six cryogenic stages were revealed for Early Pleistocene: mr2, sl, lb1b1-b2, lb2, lb3b1-b2, tl. At these times, small ice wedges, ground wedges, solifluction and different types of postcryogenic textures were formed. The cryogenic processes during the Middle Pleistocene developed more intensely. Six Middle Pleistocene cryostages were established: zv2, zv3b1-b2, or, pt2, pt3b-c, dn. The complex of cryostructures of the majority of these stages include large ice wedges, different types of ground wedges, diverse solifluction forms, and tundra spots-medallions. The largest cryogenic structures and deformations are revealed for the cold time spans during the Late Pleistocene: ice wedges (reach up to 5 m in depth), tundra spots-medallions, sand wedges, solifluction and congelifluction forms, different types of ground wedges and postcryogenic textures. Sixteen Last Pleistocene cryostages are revealed: kd1a-b, kd1b1-b2, kd2, kd3b1-b2, ts, pl1a-b, pl1b1-b2, pl1b-c, pl2, pl3b1-b2, ud, vt1b1-b2, vt2, bg, pc1, pc3. The specific features and sizes of cryostructures and cryodeformation of each cold stage, substage and phase have been used as a base for reconstruction of their geocryological conditions.

Late Quaternary Paleoenvironmental Reconstruction, Using Benthic Foraminifera and Ostracoda, of Marine Sedimentary Beds On the Southern Coast of Laizhou Bay, Bohai Sea, China

2018 ◽  
Vol 48 (2) ◽  
pp. 87-99 ◽  
Author(s):  
Xiaohui Cui ◽  
Shoujun Li ◽  
Hua Xu ◽  
Zhuo Zhang ◽  
Xiuli Zhao ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Bohai Sea ◽  
Late Quaternary ◽  
Middle Pleistocene ◽  
Small Scale ◽  
Laizhou Bay ◽  
Benthic Foraminifers ◽  
The Holocene ◽  
Subtidal Environment ◽  
Late Middle Pleistocene

Abstract Extensive studies of Quaternary transgressions have been conducted in Bohai Sea, but debates continue regarding the sedimentary evolution and timing of transgressions, especially in the Pleistocene section. Benthic foraminifers and ostracodes from three boreholes (GK138, GK111, GK95) at Laizhou Bay, Bohai Sea, were utilized to interpret the paleoenvironments of deposition and elucidate the coastal response to global sea-level changes since the late Quaternary. Benthic foraminiferal species identified included 32 species from 15 genera; ostracodes included 28 species from 16 genera. Three marine sedimentary beds were recognized based on sedimentary characteristics, down-core changes in environmental proxies (benthic foraminifers and ostracodes), accelerator mass spectrometry (AMS) 14C, and optically stimulated luminescence (OSL) dates. These three beds were interpreted as: marine sedimentary bed 3 (M3), deposited in the late-middle Pleistocene; marine sedimentary bed 2 (M2), deposited during the late Pleistocene; and marine sedimentary bed 1 (M1), deposited during the Holocene. Three microfossil assemblages were identified, all indicating nearshore conditions. Assemblage III indicated a fluvially influenced or paralic environment during a relatively small-scale late-middle Pleistocene transgression that produced bed M3. Assemblage II indicates an intertidal-subtidal environment where bed M2 was deposited during the late Pleistocene transgression. Assemblage I indicates somewhat more marine influence in a subtidal environment where bed M1 was deposited during the Holocene marine transgression.

scholarly journals A geological concept of the map sheet Rønde based on dynamic structures

1987 ◽  
Vol 8 ◽  
pp. 1-59
Author(s):  
Kaj Strand Petersen ◽  
Leif Aabo Rasmussen
Keyword(s):  
Late Pleistocene ◽  
Middle Pleistocene ◽  
The South ◽  
The Holocene ◽  
Dynamic Structures ◽  
Geological Concept ◽  
Weichselian Glaciation ◽  
Glacial Advance

During the mapping of the map sheet Rønde 1315 II an important kineto-stratigraphical frame for the Late Middle Weichselian in the central part of Denmark was demonstrated. Quaternary units are deposited on Paleogene sediments consisting of clayey Eocene-Paleocene strata to the southwest and Lower Paleocene-Danian limestone to the northeast. Middle Pleistocene till units are found as erosional remnants on the Prequaternary surface. The Late Pleistocene deposits are described within the kineto-stratigraphical concept, showing an older unit related to a glacial advance from the northeast and a younger one from the south, both belonging to the Late Middle Weichselian glaciation. Prominent extramarginal outwash sand deposits cover - the central part of the map sheet as a part of the drift unit from the south. The low-lying areas have beeen covered by the sea during the Holocene from the transgression in Early Atlantic up to the end of Subboreal. In the Subatlantic, freshwater deposits were formed, later covered by peat.

Vegetation at the northern pole of cold during the climate extremes of the late Pleistocene: fossil records from the Batagay mega thaw slump, Yakutia

2020 ◽  
Author(s):  
Frank Kienast ◽  
Kseniia Ashastina ◽  
Svetlana Kuzmina ◽  
Natalya Rudaya
Keyword(s):  
Northern Hemisphere ◽  
Late Pleistocene ◽  
Late Quaternary ◽  
Plant Cover ◽  
Climate Extremes ◽  
Environmental Stability ◽  
Middle Pleistocene ◽  
Last Interglacial ◽  
Large Herbivores ◽  
Steppe Belt

<p>The Batagay mega slump is the largest active thaw slump on the planet. Enormously rapid thermal erosion gave access to permafrost sediments that deposited since the Middle Pleistocene. Permafrost is an excellent medium for the preservation of ancient organic matter. The Batagay exposure is well known for some spectacular findings of Pleistocene megaherbivore carcasses including the youngest steppe bison found in Eurasia so far, dated to 8.2 ka BP. The extraordinarily long sequence of Pleistocene deposits in Batagay is therefore an excellent archive of the palaeoenvironmental history in the Yana highlands - a region with uniquely stable cold-continental climate known as the pole of cold in the northern hemisphere. This region is regarded as refugial area for extrazonal steppe plants and now extinct large grazers together constituting the Pleistocene mammoth steppe, which covered vast areas in high and mid latitudes of the northern hemisphere during cold stages. Modern vegetation around the study site consists of light taiga mainly composed of larch, shrub alder, shrub birches and stone pine. To understand the processes that resulted in the demise of Pleistocene megafauna and in the biological turnover during the late Quaternary, we reconstructed vegetation and environmental conditions during the two climate extremes of the late Pleistocene, the onset of the last glacial maximum and the last interglacial using remains of plants and insects preserved in organic-rich material. The results from studies of plant material gathered in a fossil ground squirrel nest suggest that grassland vegetation corresponding to modern meadow steppes in Central Yakutia and northern Mongolia existed in the study area during the last cold stage. During the last interglacial, open coniferous woodland similar to modern larch taiga was the primary vegetation at the site. Abundant charcoal indicates wildfire events during the last interglacial. Zoogenic disturbances of the local vegetation were indicated by the presence of ruderal plants, especially by the abundant nitrophytic <em>Urtica dioica</em>, suggesting that the area was an interglacial refugium for large herbivores. Meadow steppes, which formed the primary vegetation during cold stages and provided potentially suitable pastures for herbivores, were a significant constituent of the plant cover in the Yana Highlands also under the full warm stage conditions of the last interglacial. Consequently, meadow steppes occurred in the Yana Highlands during the entire investigated timespan of the Pleistocene documenting a remarkable environmental stability. The documented fossil record also proves that modern steppe occurrences in the Yana Highlands did not establish as late as in the Holocene, as suggested by some scholars, but instead are relicts of a formerly continuous steppe belt extending from Central Siberia to Northeast Yakutia during the Pleistocene.</p>

scholarly journals The Forming Age and the Evolution Process of the Brine Lithium Deposits in the Qaidam Basin Based on Geochronology and Mineral Composition

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhe Ma ◽  
Fengqing Han ◽  
Tianyuan Chen ◽  
Lei Yi ◽  
Xiaohang Lu ◽  
...  
Keyword(s):  
Mineral Composition ◽  
Late Pleistocene ◽  
Salt Lake ◽  
Qaidam Basin ◽  
Ore Deposits ◽  
Osl Dating ◽  
Tectonic Activity ◽  
Middle Pleistocene ◽  
The Holocene ◽  
Climatic Environment

Lithium ore deposits are divided into pegmatite and brine deposits. The Puna Plateau and the Qinghai–Tibetan Plateau (QTP) are home to the most abundant brine lithium deposits worldwide. Very few studies have investigated the chronology of brine lithium deposits. This paper reports the Optically Stimulated Luminescence (OSL) dating measurements for typical brine lithium deposits at QTP, including East Taijnar Salt Lake, West Taijnar Salt Lake, and Yiliping Salt Lake in the central Qaidam Basin. Combining the results of OSL dating with previous studies and mineral composition obtained by X-ray diffraction analysis (XRD), this study summarizes the age and characteristics of the climatic environment during the formation of brine lithium deposits in the Qaidam Basin. The main results are: 1) Brine lithium deposits in the Qaidam Basin began to form since 40 ka. Brine lithium deposits in South America formed during the middle Pleistocene and late Pleistocene, and are older than the deposits in the Qaidam Basin. The lithium deposits of Tibet formed around 4 ka, are the youngest. 2) The climate in East Taijnar Salt Lake and West Taijnar Salt Lake was extremely cold and dry during 27–4.6 ka, with a relatively humid climatic condition at ∼10 ka. After 4.6 ka, the environment was comparatively more humid around both lakes. Yiliping Salt Lake had a dry climate since 38.09 ka, and the climate in the Three Lakes area is mainly controlled by the westerlies in the Holocene; and 3) East Taijnar Salt Lake, West Taijnar Salt Lake and Yiliping Salt Lake were located in the same secondary basin during the late Pleistocene. However, tectonic activity around 40 ka led to the evolution of Yiliping Salt Lake into an independent basin. East Taijnar Salt Lake and West Taijnar Salt Lake separated around 27 ka, and then deposited the lower salt layers until the Holocene. The substantial amount of detrital minerals that the Nalinggele River brought during the Holocene led to a brief desalination of East Taijnar Salt Lake. The upper salt layer was deposited in East Taijnar Salt Lake and West Taijnar Salt Lake during this period due to the extremely dry climate.

Hominin transition to Upper Pliocene

2017 ◽  
Author(s):  
Francisco J. Ayala ◽  
Camilo J. Cela-Conde
Keyword(s):  
Brain Development ◽  
Late Pleistocene ◽  
Technological Progress ◽  
Homo Sapiens ◽  
Middle Pleistocene ◽  
Evolutionary Significance ◽  
Australopithecus Afarensis ◽  
Phylogenetic Significance ◽  
Homo Neanderthalensis ◽  
Surprising Discovery

This chapter analyzes the transition of the hominins from the Middle Pleistocene to the Late Pleistocene. Two alternative models are explored, the “Multiregional Hypothesis” (MH) and the “Replacement Hypothesis,” and how each model evaluates the existing relationships between the taxa Homo neanderthalensis and Homo sapiens. Next is the investigation of the transitional (or “archaic,” if this grade is taken into account) exemplars found in Europe, Africa, and Asia and their evolutionary significance. In particular, the comparison between H. erectus and H. sapiens in China and Java is investigated, as the main foundation of the MH. The chapter ends with the surprising discovery of Homo floresiensis and its description and interpretations concerning its taxonomic and phylogenetic significance. The correlation between brain development and technological progress is at odds with the attribution of perforators, microblades, and fishing hooks to a hominin with a small cranial volume, similar to that of Australopithecus afarensis.

scholarly journals Directional changes in Levallois core technologies between Eastern Africa, Arabia, and the Levant during MIS 5

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James Blinkhorn ◽  
Huw S. Groucutt ◽  
Eleanor M. L. Scerri ◽  
Michael D. Petraglia ◽  
Simon Blockley
Keyword(s):  
Homo Sapiens ◽  
Environmental Parameters ◽  
Detailed Comparison ◽  
Eastern Africa ◽  
Middle Pleistocene ◽  
Reduction Activity ◽  
Core Technology ◽  
Geographic Expansion ◽  
First Time ◽  
Mis 5

AbstractMarine Isotope Stage (MIS) 5, ~ 130 to 71 thousand years ago, was a key period for the geographic expansion of Homo sapiens, including engagement with new landscapes within Africa and dispersal into Asia. Occupation of the Levant by Homo sapiens in MIS 5 is well established, while recent research has documented complementary evidence in Arabia. Here, we undertake the first detailed comparison of Levallois core technology from eastern Africa, Arabia, and the Levant during MIS 5, including multiple sites associated with Homo sapiens fossils. We employ quantitative comparisons of individual artefacts that provides a detailed appraisal of Levallois reduction activity in MIS 5, thereby enabling assessment of intra- and inter-assemblage variability for the first time. Our results demonstrate a pattern of geographically structured variability embedded within a shared focus on centripetal Levallois reduction schemes and overlapping core morphologies. We reveal directional changes in core shaping and flake production from eastern Africa to Arabia and the Levant that are independent of differences in geographic or environmental parameters. These results are consistent with a common cultural inheritance between these regions, potentially stemming from a shared late Middle Pleistocene source in eastern Africa.

scholarly journals Pleistocene Deposits in the Southern Egyptian Sahara: Lithostratigraphic Relationships of Sediments and Landscape Dynamics at Bir Tarfawi

2017 ◽  
Vol 34 (1) ◽  
pp. 23-38
Author(s):  
Christopher L. Hill ◽  
Romuald Schild
Keyword(s):  
Groundwater Table ◽  
Middle Pleistocene ◽  
Middle Paleolithic ◽  
Stratigraphic Sequence ◽  
Climate Conditions ◽  
Green Lake ◽  
Wet Climate ◽  
Topographic Depressions ◽  
Hydrologic Conditions ◽  
Basin Fill

Abstract The sedimentological and lithostratigraphic record from north-central Bir Tarfawi documents the presence of Pleistocene basin-fill deposits. Three topographic basins were created as a result of deflation during climate episodes associated with lowering of the local groundwater table. In each case, the three deflational basins or topographic depressions were subsequently filled with sediments; these basin aggradations coincided with changes from arid climate conditions to wetter conditions and a rise in the groundwater table. The oldest and highest sedimentary remnant is associated with Acheulian artifacts and may reflect spring-fed pond and marsh conditions during a Middle Pleistocene wet climate episode. Lithofacies for a lower stratigraphic sequence (the “White Lake”) documents deposition in a perennial lake that varied in extent and depth and is associated with Middle Paleolithic artifacts. A third episode of deflation created a topographic low that has been filled with Late Pleistocene sediments that are associated with Middle Paleolithic artifacts and fossil remains. Lateral and vertical variations in the lithofacies of this basin-fill sequence and the sediments of the “grey-green” lake phases provide a record of changing hydrologic conditions. These hydrologic conditions appear to reflect variations in water-table levels related to groundwater recharge and, at times, local rains.

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