Deglacial sea level history of the East Siberian Sea and Chukchi Sea margins
Deglacial (12.8–10.7 ka) sea level history on the East Siberian continental shelf and 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 cor...
Main Authors: | , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2017-09-01
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Series: | Climate of the Past |
Online Access: | https://www.clim-past.net/13/1097/2017/cp-13-1097-2017.pdf |
Summary: | Deglacial (12.8–10.7 ka) sea level history on the East Siberian continental
shelf and 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-PC1) and multicore SWERUS-L2-4-MC1 (4-MC1), and a gravity
core from an East Siberian Sea transect, SWERUS-L2-20-GC1 (20-GC1). Cores
4-PC1 and 20-GC were taken at 120 and 115 m of modern water depth,
respectively, only a few meters above the global last glacial maximum (LGM;
∼ 24 kiloannum or ka) minimum sea level of ∼ 125–130 meters below
sea level (m b.s.l.). Using calibrated radiocarbon ages mainly on molluscs
for chronology and the ecology of benthic foraminifera and ostracode species
to estimate paleodepths, the data reveal a 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 at roughly 11.4 to 10.8 ka ( ∼ 400 cm of core depth) is indicated
by a sharp faunal change and unconformity or condensed zone of sedimentation.
Regional sea level at this time was about 108 m b.s.l. at the 4-PC1 site
and 102 m b.s.l. at 20-GC1. Regional sea level near the end of the YD was
up to 42–47 m lower than 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. |
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ISSN: | 1814-9324 1814-9332 |