Radiocarbon Chronology of Paleogeographic Events of the Late Pleistocene and Holocene in Russia

During the late Quaternary, dramatic changes in relative sea level (~170 m) are known to have occurred in the Caspian Sea. However, all previous attempts at resolving the uncertainty associated with the timing of these transgressive/regressive events, primarily using radiocarbon, have produced inconclusive or controversial results. Here we present the first reliable chronology for the largest known transgression (Early Khvalynian). This was derived using optically stimulated luminescence (OSL) analysis of sand‐sized quartz, with support from infrared stimulated luminescence (IRSL) from K‐rich feldspar grains, all extracted from 16 sediment samples collected along the Lower Volga River. These samples were taken from loessic sediments, marine clays (known as Chocolate Clays) and the overlying modern soils exposed at three sections (Srednyaya Akhtuba, Raygorod, Leninsk) ~200 km upstream of the present‐day estuary. The differential bleaching rates of the quartz OSL and feldspar IRSL signals were used to evaluate the degree of resetting of quartz (and feldspar) signals; it was possible to conclude that all signals, and particularly quartz OSL, were sufficiently reset at deposition to allow accurate age estimation. Our results show unambiguously that the Early Khvalynian marine Chocolate Clays present at all three sections were deposited post‐LGM, between ~17 and ~13.1 ka ago. These age estimates are further constrained by those from the overlying Kastanozem soils (9.6–0.7 ka) and underlying loess‐soil series (32–19 ka), confirming a young (17–13 ka) age of the transgressive stage of the Early Khvalynian. Relative sea level during this period must have been well above the sampling altitudes of 11.7 m a.s.l. (Srednyaya Akhtuba), 11.3 m a.s.l. (Raygorod) and 4.7 m a.s.l. (Leninsk) to explain the absence of significant alluvial sand and to allow the deposition of the fine Chocolate Clays marker horizon.

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“…2002, 2016), and radiocarbon (Kaplin et al . 1993; Svitoch et al . 1994; Badyukova 2007; Tudryn et al .…”

Section: Figmentioning

confidence: 99%

First reliable chronology for the Early Khvalynian Caspian Sea transgression in the Lower Volga River valley

Kurbanov

Murray

Thompson

et al. 2020

Boreas

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“…late Kvalynian transgression to somewhere between 14 and 9 ky BP (Kaplin et al 1993). However, the Caspain discharge into the Black Sea can be better refined using fragments of wood and individual mollusk shells in the diatom deposit that have dates of 10.7 and 10.6 ky BP, respectively.…”

Section: Timing the Fresheningmentioning

confidence: 99%

Catastrophic Flooding of the Black Sea

Ryan

Major

Lericolais

et al. 2003

Annu. Rev. Earth Planet. Sci.

260

162

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Decades of seabed mapping, reflection profiling, and seabed sampling reveal that throughout the past two million years the Black Sea was predominantly a freshwater lake interrupted only briefly by saltwater invasions coincident with global sea level highstand. When the exterior ocean lay below the relatively shallow sill of the Bosporus outlet, the Black Sea operated in two modes. As in the neighboring Caspian Sea, a cold climate mode corresponded with an expanded lake and a warm climate mode with a shrunken lake. Thus, during much of the cold glacial Quaternary, the expanded Black Sea's lake spilled into to the Marmara Sea and from there to the Mediterranean. However, in the warm climate mode, after receiving a vast volume of ice sheet meltwater, the shoreline of the shrinking lake contracted to the outer shelf and on a few occasions even beyond the shelf edge. If the confluence of a falling interior lake and a rising global ocean persisted to the moment when the rising ocean penetrated across the dividing sill, it would set the stage for catastrophic flooding. Although recently challenged, the flood hypothesis for the connecting event best fits the full set of observations. PREFACE The hypothesis of an abrupt flooding of the Black Sea arose from the results of a Russian-American expedition in 1993 that surveyed and sampled the continental shelf south of the Kerch Strait and west of the Crimea (Ryan et al. 1997a, Ryan et al. 1997b). Essential to this new and now controversial idea were (a) extremely-highresolution seismic-reflection profiles, (b) cores precisely targeted on these profiles, and (c) dating by 14 C accelerator mass spectrometry (see Ryan & Pitman 1999 for a narrative text of the discoveries and the deductive processes). The reflection profiles revealed a ubiquitous erosion surface that crossed the shelf to depths of −150-m beyond the shelf break. The cores recovered evidence of subaerial mud cracks at −99 m, algae remains at −110 m, and the roots of shrubs in place in

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“…The numerous Caspian transgressions that occurred since the Miocene and throughout the Pleistocene are the main processes that led to the formation of the LVV and its adjacent areas ( Kroonenberg et al 1997 ; Svitoch 2008 ; Badyukova 2010 ). However, there is little agreement regarding the chronology and paleogeographical details of the Caspian transgressions and how they affected the formation of various areas in the LVV ( Kaplin et al 1993 ; Krooneberg et al 1997 ; Dumont 1998 ; Svitoch 2008 ).…”

Section: Discussionmentioning

confidence: 99%

“…The genesis of the modern Volga River and its Delta dates back from the Pliocene when glaciation cycles have largely contributed to a series of dramatic transgression events that culminated with the Late Khvalyn phase (the last major transgression in the Pleistocene) and were intercalated by regression events that include the current Novocaspian phase ( Kroonenberg et al 1997 ; Mamedov 1997 ; Dumont 1998 ). Although the sequence of events is not controversial, the actual chronology is still unclear and debated in the literature despite the numerous 14 C dates generated by various studies ( Kaplin et al 1993 ; Kroonenberg et al 1997 ; Mamedov 1997 ; Dumont 1998 ). Overall, the last transgression event, with all of its phases, may have occurred approximately within 16–7 ka ago ( Svitoch 2008 ), although older dates are provided by Kaplin et al (1993) , Kroonenberg et al (1997) , Mamedov (1997) , and Dumont (1998) .…”

Section: Introductionmentioning

confidence: 99%

“…Although the sequence of events is not controversial, the actual chronology is still unclear and debated in the literature despite the numerous 14 C dates generated by various studies ( Kaplin et al 1993 ; Kroonenberg et al 1997 ; Mamedov 1997 ; Dumont 1998 ). Overall, the last transgression event, with all of its phases, may have occurred approximately within 16–7 ka ago ( Svitoch 2008 ), although older dates are provided by Kaplin et al (1993) , Kroonenberg et al (1997) , Mamedov (1997) , and Dumont (1998) .…”

Section: Introductionmentioning

confidence: 99%

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A maximum likelihood approach to generate hypotheses on the evolution and historical biogeography in the Lower Volga Valley regions (southwest Russia)

Mavrodiev

Лактионов

Cellinese

2012

Ecology and Evolution

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The evolution of the diverse flora in the Lower Volga Valley (LVV) (southwest Russia) is complex due to the composite geomorphology and tectonic history of the Caspian Sea and adjacent areas. In the absence of phylogenetic studies and temporal information, we implemented a maximum likelihood (ML) approach and stochastic character mapping reconstruction aiming at recovering historical signals from species occurrence data. A taxon-area matrix of 13 floristic areas and 1018 extant species was constructed and analyzed with RAxML and Mesquite. Additionally, we simulated scenarios with numbers of hypothetical extinct taxa from an unknown palaeoflora that occupied the areas before the dramatic transgression and regression events that have occurred from the Pleistocene to the present day. The flora occurring strictly along the river valley and delta appear to be younger than that of adjacent steppes and desert-like regions, regardless of the chronology of transgression and regression events that led to the geomorphological formation of the LVV. This result is also supported when hypothetical extinct taxa are included in the analyses. The history of each species was inferred by using a stochastic character mapping reconstruction method as implemented in Mesquite. Individual histories appear to be independent from one another and have been shaped by repeated dispersal and extinction events. These reconstructions provide testable hypotheses for more in-depth investigations of their population structure and dynamics.

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Radiocarbon Chronology of Paleogeographic Events of the Late Pleistocene and Holocene in Russia

Cited by 7 publications

References 1 publication

First reliable chronology for the Early Khvalynian Caspian Sea transgression in the Lower Volga River valley

First reliable chronology for the Early Khvalynian Caspian Sea transgression in the Lower Volga River valley

Catastrophic Flooding of the Black Sea

A maximum likelihood approach to generate hypotheses on the evolution and historical biogeography in the Lower Volga Valley regions (southwest Russia)

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