T17 From the Caspian to Mediterranean: Environmental Change and Human Response during the Quaternary (INQUA IFG POCAS, IGCP 610) I

Sunday, 10 October 2021
8:00 AM - 12:00 PM
ONLINE

THE KARANGATIAN EPOCH IN THE AZOV-BLACK SEA (PONT) BASIN: STRATIGRAPHY, PALEOGEOGRAPHY, CORRELATIONS, GEOLOGICAL HISTORY

Paper number: T17-14
Program: Technical Sessions
Time: 11:20 AM – 11:35 AM

Authors

Abstract

The Karangatian transgression is a significant milestone in the Pleistocene history of the Azov-Black Sea (referred to here as the Pont); it was a large interglacial transgression by Mediterranean water that increased the level and salinity of the Pont above present values. Karangatian deposits are found almost everywhere across the Pont and are well studied by multidisciplinary methods. All researchers agree with their stratigraphic position and their possession of different fossil Mediterranean groups of organisms that do not live in the Pont today.

There are about 100 chronometric dates for Karangatian deposits. Radiocarbon dates range between 23.88±0.49 ka BP and 42.12±0.9 ka BP but cannot be considered due to the age limitations of the method. U/Io dates range between 90.6±3.1 ka and 125.0±5.0 ka, while U/Th dates vary from 33.1±2.8 to 127.0±8.9 ka. The results of OSL dating range between 102±7 ka and 131±10 ka.

According to commonly accepted opinion, Karangatian deposits (sensu lato) accumulated during Riss-Würm correspond to MIS 5 and contain layers with anomalous directions of the NRM (Natural Remanent Magnetization) vector, including a direct, reverse, and intermediate polarity dated ~125–100 ka, thus corresponding to the Blake anomalous horizon.

The palynological data show that the Mikulinian (Eemian) Interglacial includes a rapid warming expressed by pollen proxy-temperature data at onshore sites during the end of MIS 6, as well as during the whole of MIS 5. This palynological proxy-temperature signal was used to extend the Mikulinian stage from 145–140 up to 70 ka, although it differs from the standard marine oxygen isotopic data that are the basis for the global MIS reference record. The dinoflagellate cysts in cores of Karangatian sediment from the Pont do not show the early warming or salinization of surface water.

All researchers agree that salinity in the Karangatian basin was highest (~30 psu) in the Quaternary. However, based on different fossils, it was changeable: being low (~11 psu) at the beginning and end and highest (~30 psu) in the middle of the Karangatian epoch.

The purpose of this presentation is to provide a comprehensive overview of the geological history of the Pont during Karangatian time. This includes (but is not restricted to) stratigraphy, paleogeography, correlations with adjacent basins (Mediterranean and Caspian), and climate changes using multidisciplinary data as the main tools.

Geological Society of America Abstracts with Programs. Vol. 53, No. 6

doi: 10.1130/abs/2021AM-364553

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