Upwelling conditions and sea surface temperature off Northern California during early Pliocene
The early Pliocene is the most recent time in Earth history when average global temperatures were warmer than today. We present alkenone-derived SST estimates from ODP Site 1022 (40??N, 125??W, 1950m water depth) off northern California from the early Pliocene (4.2-2.8 Ma). The 2.8??C cooling is con...
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San Francisco State University
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ftcalifstateuniv:oai:dspace.calstate.edu:10211.3/98603 2023-05-15T18:28:23+02:00 Upwelling conditions and sea surface temperature off Northern California during early Pliocene Reed, Chelsea Marie Earth & Climate Sciences 2010 http://hdl.handle.net/10211.3/98603 en_US eng San Francisco State University http://hdl.handle.net/10211.3/98603 Copyright by Chelsea Marie Reed, 2010 AS36 2010 GEOL .R44 Thesis 2010 ftcalifstateuniv 2022-04-13T11:10:16Z The early Pliocene is the most recent time in Earth history when average global temperatures were warmer than today. We present alkenone-derived SST estimates from ODP Site 1022 (40??N, 125??W, 1950m water depth) off northern California from the early Pliocene (4.2-2.8 Ma). The 2.8??C cooling is consistent with previously published records from the southern California margin. In order to determine the cause of the cooling SST trend, diatom assemblages were used to constrain oceanographic conditions. The proportion of subarctic diatoms is unchanged from 4.2 to 3 Ma, suggesting a change in the strength of the California current cannot explain the cooling. The proportion of upwelling-indicative diatoms also shows no trend. Alkenone concentrations, diatom preservation, biosilica, and total organic carbon confirm that the upwelling of nutrientrich subsurface water did not change as SST cooled. Upwelling of nutrient-rich water while SST were warmer can be explained by a deeper early Pliocene thermocline. Thesis Subarctic California State University (CSU): DSpace |
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Open Polar |
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California State University (CSU): DSpace |
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ftcalifstateuniv |
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English |
description |
The early Pliocene is the most recent time in Earth history when average global temperatures were warmer than today. We present alkenone-derived SST estimates from ODP Site 1022 (40??N, 125??W, 1950m water depth) off northern California from the early Pliocene (4.2-2.8 Ma). The 2.8??C cooling is consistent with previously published records from the southern California margin. In order to determine the cause of the cooling SST trend, diatom assemblages were used to constrain oceanographic conditions. The proportion of subarctic diatoms is unchanged from 4.2 to 3 Ma, suggesting a change in the strength of the California current cannot explain the cooling. The proportion of upwelling-indicative diatoms also shows no trend. Alkenone concentrations, diatom preservation, biosilica, and total organic carbon confirm that the upwelling of nutrientrich subsurface water did not change as SST cooled. Upwelling of nutrient-rich water while SST were warmer can be explained by a deeper early Pliocene thermocline. |
author2 |
Earth & Climate Sciences |
format |
Thesis |
author |
Reed, Chelsea Marie |
spellingShingle |
Reed, Chelsea Marie Upwelling conditions and sea surface temperature off Northern California during early Pliocene |
author_facet |
Reed, Chelsea Marie |
author_sort |
Reed, Chelsea Marie |
title |
Upwelling conditions and sea surface temperature off Northern California during early Pliocene |
title_short |
Upwelling conditions and sea surface temperature off Northern California during early Pliocene |
title_full |
Upwelling conditions and sea surface temperature off Northern California during early Pliocene |
title_fullStr |
Upwelling conditions and sea surface temperature off Northern California during early Pliocene |
title_full_unstemmed |
Upwelling conditions and sea surface temperature off Northern California during early Pliocene |
title_sort |
upwelling conditions and sea surface temperature off northern california during early pliocene |
publisher |
San Francisco State University |
publishDate |
2010 |
url |
http://hdl.handle.net/10211.3/98603 |
genre |
Subarctic |
genre_facet |
Subarctic |
op_source |
AS36 2010 GEOL .R44 |
op_relation |
http://hdl.handle.net/10211.3/98603 |
op_rights |
Copyright by Chelsea Marie Reed, 2010 |
_version_ |
1766210836621164544 |