Carbonate dissolution episodes in Paleocene and Eocene sediment, Shatsky Rise, west-central Pacific

Hancock, Haidi J.L., and Dickens, Gerald R. (2006) Carbonate dissolution episodes in Paleocene and Eocene sediment, Shatsky Rise, west-central Pacific. Proceedings of the Ocean Drilling Program. Scientific Results, 198. 198SR-. pp. 1-24.

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Abstract

Holes 1209A and 1211A on Southern High, Shatsky Rise contain expanded, nearly continuous records of carbonate-rich sediment deposited in deep water of the equatorial Pacific Ocean during the Paleocene and Eocene. In this study, we document intervals of carbonate dissolution in these records by examining temporal changes in four parameters: carbonate content, coarse size fraction (>38 µm), benthic foraminiferal abundance, and planktonic foraminiferal fragmentation ratio. Carbonate content is not a sensitive indicator of carbonate dissolution in the studied sections, although rare intervals of low carbonate may reflect times of relatively high dissolution. The proportion of coarse size fraction does not accurately record carbonate dissolution either because the relative abundance of nannofossils largely determines the grain-size distribution. Benthic abundance and fragmentation covary (r2 = 0.77) and are probably the best indicators for carbonate dissolution. For both holes, records of these parameters indicate two episodes of prominent dissolution. The first of these occurs in the upper Paleocene (~59–58 Ma) and the second in the middle to upper Eocene (~45–33.7 Ma). Other intervals of enhanced carbonate dissolution are located in the upper Paleocene (~56 Ma) and in the upper lower Eocene (~51 Ma). Enhanced preservation of planktonic foraminiferal assemblages marks the start of both the Paleocene and Eocene epochs.

Item ID: 4612
Item Type: Article (Research - C1)
ISSN: 1096-7451
Keywords: carbonate; dissolution; Paleogene; Pacific; foraminifera; carbon cycle
Additional Information:

Reproduced with permission from the Proceedings of the Ocean Drilling Program Scientific Results.

Hancock, Haidi J.L., and Dickens, Gerald R. (2006) Carbonate dissolution episodes in Paleocene and Eocene sediment, Shatsky Rise, west-central Pacific. Proceedings of the Ocean Drilling Program Scientific Results, 198 . pp. 1-24. Doi: 10.2973/odp.proc.sr.198.116.2005

Date Deposited: 11 Sep 2009 03:59
SEO Codes: 96 ENVIRONMENT > 9603 Climate and Climate Change > 960399 Climate and Climate Change not elsewhere classified @ 100%
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