Snapshot-records from bivalves reveal seasonal changes in Eurasian paleohydrologyтезисы доклада

Дата последнего поиска статьи во внешних источниках: 4 сентября 2019 г.

Работа с тезисами доклада


[1] Snapshot-records from bivalves reveal seasonal changes in eurasian paleohydrology / H. A. Bauch, Y. Ovsepyan, O. Rudenko et al. // American Geophysical Union Fall Meeting Abstracts. — ID# 370319, Poster Number: GC33D-1402. — United States: United States, 2018. — P. PP33C–1734–PP33C–1734. Little is known from arctic-subarctic regions concerning ultra-high resolution of warm climate conditions beyond the present interglacial. So far, stable isotopes of bivalve records from the Siberian Arctic shelf have been used succesfully to established insight into the seasonal forcing behind Holocene paleohydrological changes. Combined with other proxy data, these snapshot records, which cover the past 9 ka, reflect the varying precipitation over the region through freshwater-runoff by the vast Siberian river system that drains northward into the Arctic Ocean. In comparsion to the Holocene nothing similar in seasonal resolution is known from the North Eurasian margin with regard to the Eemian warm period. Supported by a series of faunal, floral as well as sedimentological data we have investigated and reconstructed the paleoenvironmental history of last interglacial marine sediments deposited in northern Russia during and after the Boreal (penultimate) global transgression. All fossil data, including bivalve assemblages, give vivid evidence of major hydrological changes in the study area: early sediments feature a period of harsh, fluvially-affected environmental conditions with cold turbid waters and heavy seasonal sea-ice cover, while the later phase, which consists of a typical Arctic shelf and deep-sea microfossil assemblage together with broad-leaved pollen, implies peak interglacial conditions. It is in this later part that we found an abundance of in-situ specimens of the long-lived species Arctica islandica. Analysing the stable oxygen isotopes we were able to establish a 258-years long record that provides us with a first high-resolution record of hydrological changes in the sub-Arctic during Eemian times.

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