C43A-0777
Holocene Ostracoda from the Herald Canyon, Eastern Siberian Sea from the SWERUS-C3 Expedition 2014
Thursday, 17 December 2015
Poster Hall (Moscone South)
Laura Gemery1, Thomas M Cronin2, Martin Jakobsson3, Natalia Barrientos4, Matthew O’Regan3, Francesco Muschitiello3, Andrey Koshurnikov5 and Alexander Gukov6, (1)USGS Headquarters, Reston, VA, United States, (2)U.S. Geological Survey, Reston, Virginia, USA, VA, United States, (3)Stockholm University, Department of Geological Sciences, Stockholm, Sweden, (4)Stockholm University, Stockholm, Sweden, (5)Lomonosov Moscow State University, Moscow, Russia, (6)National Tomsk Research Polytech University, Russia, Tomsk, Russia
Abstract:
We analyzed Arctic benthic ostracode assemblages from two piston cores (PC) and their complementary multicores from Herald Canyon in the Eastern Siberian Sea. The cores (SWERUS-L2-2-PC1 [8.1 m], 2-MUC4, 71.7 m water depth, and SWERUS-L2-4-PC1 [6.2 m], 4-MUC4, 119.7 m water depth) were collected during Leg 2 of the 2014 SWERUS-C3 Expedition. Radiocarbon dates on mollusks indicate that sediments from 2-PC1 and 4-PC1 were deposited over the last 5,000 and 10,000 years respectively. The dominant ostracode species include: Acanthocythereis dunelmensis, Cytheropteron elaeni, Elofsonella concinna, Kotoracythere janae, Normanicythere leioderma, Semicytherura complanata. Based on species’ distributions obtained from a 1,200-sample modern ostracode database, these species are known to be typical of shallow mid- to outer-continental shelf environments in the modern Arctic Ocean. The abundant and diverse benthic ostracode assemblages found in these cores suggest the influence of nutrient-rich Pacific water flowing in through the Bering Strait. The faunal assemblages are fairly uniform throughout 2-PC1, suggesting minimal variability in Pacific water inflow since at least 5 ka. In the lower section of 4-PC1, there is a major change to ostracode assemblages containing typical inner shelf, often brackish-water species, such as Cytheromorpha macchesneyi, and associated shallow Arctic shelf species (Sarsicytheridea punctillata and several Cytheropteron species), reflecting a period of lower, deglacial sea level.
