(Table S1) Age determination of sediment cores of the Gulf of Alaska


Oxygen isotope data from planktonic and benthic foraminifera, on a high-resolution age model (44 14C dates spanning 17,400 years), document deglacial environmental change on the southeast Alaska margin (59°33.32'N, 144°9.21'W, 682 m water depth). Surface freshening (i.e., d18O reduction of 0.8 per mil) began at 16,650 ± 170 cal years B.P. during an interval of ice proximal sedimentation, likely due to freshwater input from melting glaciers. A sharp transition to laminated hemipelagic sediments constrains retreat of regional outlet glaciers onto land circa 14,790 ± 380 cal years B.P. Abrupt warming and/or freshening of the surface ocean (i.e., additional d18O reduction of 0.9 per mil) coincides with the Bølling Interstade of northern Europe and Greenland. Cooling and/or higher salinities returned during the Allerød interval, coincident with the Antarctic Cold Reversal, and continue until 11,740 ± 200 cal years B.P., when onset of warming coincides with the end of the Younger Dryas. An abrupt 1 per mil reduction in benthic d18O at 14,250 ± 290 cal years B.P. likely reflects a decrease in bottom water salinity driven by deep mixing of glacial meltwater, a regional megaflood event, or brine formation associated with sea ice. Two laminated opal-rich intervals record discrete episodes of high productivity during the last deglaciation. These events, precisely dated here at 14,790 ± 380 to 12,990 ± 190 cal years B.P. and 11,160 ± 130 to 10,750 ± 220 cal years B.P., likely correlate to similar features observed elsewhere on the margins of the North Pacific and are coeval with episodes of rapid sea level rise. Remobilization of iron from newly inundated continental shelves may have helped to fuel these episodes of elevated primary productivity and sedimentary anoxia.

Calendar years calculated from mean planktonic 14C ages for JC and TC samples and benthic 14C ages for MC samples, using CALIB v.6.0 [Stuiver and Reimer, 1993] with the Marine09 calibration curve. For planktonic samples (JC and TC) Delta R = 470 ± 80 years, and for benthic samples (MC) Delta R = 900 ± 100.

Supplement to: Davies, M H; Mix, Alan C; Stoner, Joseph S; Addison, Jason A; Jaeger, John; Finney, Bruce P; Wiest, Johannes (2011): The deglacial transition on the southeastern Alaska Margin: Meltwater input, sea level rise, marine productivity, and sedimentary anoxia. Paleoceanography, 26(2), PA2223

DOI https://doi.org/10.1594/PANGAEA.830645
Related Identifier IsSupplementTo https://doi.org/10.1029/2010PA002051
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.830645
Creator Davies, M H ORCID logo; Mix, Alan C ORCID logo; Stoner, Joseph S ORCID logo; Addison, Jason A ORCID logo; Jaeger, John (ORCID: 0000-0003-0248-489X); Finney, Bruce P; Wiest, Johannes
Publisher PANGAEA
Publication Year 2011
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 206 data points
Discipline Earth System Research
Spatial Coverage (-144.154W, 59.555S, -144.153E, 59.555N); Gulf of Alaska