Deglacial sea-level history of the East Siberian Sea Margin
Thomas M. Cronin1, Matt O'Regan2, Christof Pearce2, Laura Gemery1, Michael Toomey1, Igor Semiletov3,4, and Martin Jakobsson21US Geological Survey MS926A, Reston, Virginia, 20192, USA 2Department of Geological Sciences and Bolin Centre for Climate Research, Stockholm University, Stockholm, 10691, Sweden 3Pacific Oceanological Institute, Russian Academy Sciences, Vladivostok, Russia 4Tomsk National Research Polytechnic University, Tomsk, Russia
Received: 13 Feb 2017 – Accepted for review: 23 Mar 2017 – Discussion started: 29 Mar 2017
Abstract. Abstract. Deglacial (12.8–10.7 ka) sea-level history on the East Siberian continental shelf/upper continental slope was reconstructed using new geophysical records and sediment cores taken during Leg 2 of the 2014 SWERUS-C3 expedition. The focus of this study is two cores from Herald Canyon, piston core SWERUS-L2-4-PC1 (4-PC) and multicore SWERUS-L2-4-MC1 (4-MC1) and a gravity core from an East Siberian Sea Transect, SWERUS-L2-20-GC1 (20-GC). Cores 4-PC1 and 20-GC were taken at 120 m and 115 m modern water depth, respectively, only a few meters above the global last glacial maximum (LGM, ~ 24 kiloannum (ka)) minimum sea level of ~ 125–130 meters below sea level (mbsl). Using calibrated radiocarbon ages mainly on molluscs for chronology and the ecology of benthic foraminifera and ostracode species to estimate paleo-depths, the data reveal dominance of river-proximal species during the early part of the Younger Dryas event (YD, Greenland Stadial GS-1) followed by a rise in river-intermediate species in the late Younger Dryas or the early Holocene (Preboreal) period. A rapid relative sea-level rise beginning roughly 11.4 to 10.8 ka (~ 400 cm core depth) during is indicated by a sharp faunal change and unconformity or condensed zone of sedimentation. Regional sea level at this time was about 108 mbsl at the 4-PC1 site and 102 mbsl at 20-GC. Regional sea-level during the YD was about 40 to 50 meters lower than those predicted by geophysical models corrected for glacio-isostatic adjustment. This discrepancy could be explained by delayed isostatic adjustment caused by a greater volume and/or geographical extent of glacial-age land ice and/or ice shelves in the western Arctic Ocean and adjacent Siberian land areas.
Cronin, T. M., O'Regan, M., Pearce, C., Gemery, L., Toomey, M., Semiletov, I., and Jakobsson, M.: Deglacial sea-level history of the East Siberian Sea Margin, Clim. Past Discuss., doi:10.5194/cp-2017-19, in review, 2017.