Compilation of geophysical, geochronological, and geochemical evidence indicates a rapid Mediterranean-derived submergence of the Black Sea\textquotesingles shelf and subsequent substantial salinification in the early Holocene

Yanchilina, A.G.; Ryan William, B.F.; McManus, J.F.; Dimitrov, P.; Dimitrov, D.; Slavova, K.; Filipova-Marinova, M.

Авторы: Yanchilina Anastasia G., Ryan William B.F., McManus Jerry F., Dimitrov Petko, Dimitrov Dimitar, Slavova Krasimira, Filipova-Marinova Mariana
Журнал: Marine Geology
Том: 383
Год издания: 2017
Издательство: Elsevier BV
Местоположение издательства: Netherlands
Первая страница: 14
Последняя страница: 34
DOI: 10.1016/j.margeo.2016.11.001
Аннотация: Our knowledge of rate and processes in which semi-enclosed environments alternate fromlacustrine to marine is commonly limited because of the paucity of speciﬁc proxies for sea level and salinity. Here we investigate the timing, rate, and key mechanisms involved in the transformation of the previously isolated Black Sea-Lake to the modern partly-enclosed marine sea using a suite of geophysical, geochemical, and geochronological methods. Cores were collected in transects across shelves of Ukraine, Romania, Bulgaria, and Turkey. Biogenic carbonate fromthese cores was analyzed for radiocarbon and strontium, oxygen, and carbon isotopes. Strontiumresults indicate that the submergence of the Black Sea shelf at 9300 calendar years BP was caused by the ingress of Mediterranean water and was abrupt, taking b40 years. The seismic reﬂection proﬁles show a uniform drape of subsequent sediment over aeolian dunes indicating a drowning with no time for erosion accompanying the submergence. Moisture measurements beneath the uniform drape indicate that the shelf was dry before submergence and the shoreline of the Preboreal lake may have regressed to beyond 120 mbsl. Mollusks colonized the newly submerged substrate of the inner shelf at the same time as they colonized the outer shelf. The succession of mollusk species with shells whose strontium isotope composition has a marine component indicates a rising salinity. The transformation of the lake to a sea is afﬁrmed by increases in the shells' strontium and oxygen isotopic ratios towards the external ocean value. Radiocarbon years are calibrated to calendar years by tuning the oxygen and carbon isotope composition of the mollusk record to that of the U/Th dated Sofular Cave stalagmites. The match shows a reduction of the lake's prior high reservoir age accompanying the inﬂow of the Mediterranean water. In 900 years the salinity reached a threshold that excluded all previous Black Sea lacustrine fauna. These results imply that any substantial postglacial submergence of the Black Sea shelves did not occur prior to entry of Mediterranean water.
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Compilation of geophysical, geochronological, and geochemical evidence indicates a rapid Mediterranean-derived submergence of the Black Sea\textquotesingles shelf and subsequent substantial salinification in the early Holoceneстатья Исследовательская статья

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