Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry
High-resolution records of diatoms, silicoflagellates, and geochemistry covering the past 15,000 years were studied in three cores from the Gulf of Alaska (GOA). Core EW0408-85JC in an oceanic setting on the Kayak Slope displays a paleoceanographic record similar to that at several locations on the...
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2009
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ftunivnebraskali:oai:digitalcommons.unl.edu:usgsstaffpub-1323 2023-11-12T04:26:00+01:00 Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry Barron, John A. Bukry, David Dean, Walter E. Addison, Jason A. Finney, Bruce 2009-01-01T08:00:00Z application/pdf https://digitalcommons.unl.edu/usgsstaffpub/326 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1323/viewcontent/Dean_MM_2009_Paleoceanography_Gulf_Alaska.pdf unknown DigitalCommons@University of Nebraska - Lincoln https://digitalcommons.unl.edu/usgsstaffpub/326 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1323/viewcontent/Dean_MM_2009_Paleoceanography_Gulf_Alaska.pdf USGS Staff -- Published Research Earth Sciences text 2009 ftunivnebraskali 2023-10-30T10:44:07Z High-resolution records of diatoms, silicoflagellates, and geochemistry covering the past 15,000 years were studied in three cores from the Gulf of Alaska (GOA). Core EW0408-85JC in an oceanic setting on the Kayak Slope displays a paleoceanographic record similar to that at several locations on the California margin during deglaciation. Biologic productivity as reconstructed using geochemical and microfossil proxies increased abruptly during the Bølling–Alleröd (Bø–Al) warm interval (14.7–12.9 cal ka), declined during the Younger Dryas (YD) cold interval (12.9 to 11.7 cal kyr BP), and rose again during the earliest Holocene. At this site, the record after ~11 cal kyr BP is dominated by oceanic diatoms and silicoflagellates, with geochemical proxies displaying more subtle variation. Cores EW0408-66JC in the Yakobi Sea Valley near Cross Sound and EW0408-11JC in the Gulf of Esquibel contain an expanded, composite record along the southeast Alaskan margin. Core 66JC contains a detailed record of the Bø–Al and YD. Diatoms and silicoflagellates indicate that coastal upwelling and biosiliceous productivity were strong during the Bø–Al but declined during the YD. Sea ice-related diatoms increased in abundance during the YD, indicating cooler, but less productive waters. The glacial to biogenic marine sediment transition in core 11JC occurs at 1280 cmbsf (centimeters below sea floor), probably representing rising sea level and deglaciation early in the Bø–Al. Freshwater and sea-ice related diatoms are common in the lower part of the core (Bø–Al and YD), but upwelling-related diatoms and silicoflagellates quickly increased in relative abundance up-core, dominating the record of the past 11,000 years. Low oxygen conditions in the bottom water as reconstructed using geochemical proxies (U and Mo concentration) were most intense between ~6.5 and 2.8 cal kyr BP, the beginning of which is coincident with increases in abundance of upwelling-related diatoms. The records from these three cores jointly thus made it possible to ... Text Sea ice Alaska University of Nebraska-Lincoln: DigitalCommons@UNL Gulf of Alaska Pacific Kayak ENVELOPE(103.217,103.217,71.533,71.533) Bø ENVELOPE(12.567,12.567,66.167,66.167) |
institution |
Open Polar |
collection |
University of Nebraska-Lincoln: DigitalCommons@UNL |
op_collection_id |
ftunivnebraskali |
language |
unknown |
topic |
Earth Sciences |
spellingShingle |
Earth Sciences Barron, John A. Bukry, David Dean, Walter E. Addison, Jason A. Finney, Bruce Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry |
topic_facet |
Earth Sciences |
description |
High-resolution records of diatoms, silicoflagellates, and geochemistry covering the past 15,000 years were studied in three cores from the Gulf of Alaska (GOA). Core EW0408-85JC in an oceanic setting on the Kayak Slope displays a paleoceanographic record similar to that at several locations on the California margin during deglaciation. Biologic productivity as reconstructed using geochemical and microfossil proxies increased abruptly during the Bølling–Alleröd (Bø–Al) warm interval (14.7–12.9 cal ka), declined during the Younger Dryas (YD) cold interval (12.9 to 11.7 cal kyr BP), and rose again during the earliest Holocene. At this site, the record after ~11 cal kyr BP is dominated by oceanic diatoms and silicoflagellates, with geochemical proxies displaying more subtle variation. Cores EW0408-66JC in the Yakobi Sea Valley near Cross Sound and EW0408-11JC in the Gulf of Esquibel contain an expanded, composite record along the southeast Alaskan margin. Core 66JC contains a detailed record of the Bø–Al and YD. Diatoms and silicoflagellates indicate that coastal upwelling and biosiliceous productivity were strong during the Bø–Al but declined during the YD. Sea ice-related diatoms increased in abundance during the YD, indicating cooler, but less productive waters. The glacial to biogenic marine sediment transition in core 11JC occurs at 1280 cmbsf (centimeters below sea floor), probably representing rising sea level and deglaciation early in the Bø–Al. Freshwater and sea-ice related diatoms are common in the lower part of the core (Bø–Al and YD), but upwelling-related diatoms and silicoflagellates quickly increased in relative abundance up-core, dominating the record of the past 11,000 years. Low oxygen conditions in the bottom water as reconstructed using geochemical proxies (U and Mo concentration) were most intense between ~6.5 and 2.8 cal kyr BP, the beginning of which is coincident with increases in abundance of upwelling-related diatoms. The records from these three cores jointly thus made it possible to ... |
format |
Text |
author |
Barron, John A. Bukry, David Dean, Walter E. Addison, Jason A. Finney, Bruce |
author_facet |
Barron, John A. Bukry, David Dean, Walter E. Addison, Jason A. Finney, Bruce |
author_sort |
Barron, John A. |
title |
Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry |
title_short |
Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry |
title_full |
Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry |
title_fullStr |
Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry |
title_full_unstemmed |
Paleoceanography of the Gulf of Alaska During the Past 15,000 Years: Results From Diatoms, Silicoflagellates, and Geochemistry |
title_sort |
paleoceanography of the gulf of alaska during the past 15,000 years: results from diatoms, silicoflagellates, and geochemistry |
publisher |
DigitalCommons@University of Nebraska - Lincoln |
publishDate |
2009 |
url |
https://digitalcommons.unl.edu/usgsstaffpub/326 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1323/viewcontent/Dean_MM_2009_Paleoceanography_Gulf_Alaska.pdf |
long_lat |
ENVELOPE(103.217,103.217,71.533,71.533) ENVELOPE(12.567,12.567,66.167,66.167) |
geographic |
Gulf of Alaska Pacific Kayak Bø |
geographic_facet |
Gulf of Alaska Pacific Kayak Bø |
genre |
Sea ice Alaska |
genre_facet |
Sea ice Alaska |
op_source |
USGS Staff -- Published Research |
op_relation |
https://digitalcommons.unl.edu/usgsstaffpub/326 https://digitalcommons.unl.edu/context/usgsstaffpub/article/1323/viewcontent/Dean_MM_2009_Paleoceanography_Gulf_Alaska.pdf |
_version_ |
1782340147318095872 |