Major components and major and trace elements from ODP Site 175-1085

We have analyzed 33 Pliocene bulk sediment samples from Ocean Drilling Program Site 1085 in the Cape Basin, located offshore of western Africa in the Angola-Benguela Current system, for 17 major and trace elements, and interpreted their associations and temporal variations in the context of an allied data set of CaCO3, opal, and Corg. We base our interpretations on elemental ratios, accumulation rates, inter-element correlations, and several multi-element statistical techniques. On the basis of qualitative assessment of downhole changes in the distributions of P and Ba, utilized as proxies of export production, we conclude that highs in bulk and biogenic accumulation that occur at 3.2 Ma, 3.0 Ma, 2.4 Ma, and 2.25 Ma were caused by increases in export production as well as terrigenous flux, and record a greater sequestering of organic matter during these time periods. Studies of refractory elements and other indicator proxies (SiO2, Al2O3, TiO2, Fe2O3, MgO, V, Cr, Sr, and Zr) strongly suggest that the terrigenous component of the bulk sediment is composed of two compositional end-members, one being 'basaltic' in composition and the other similar to an 'average shale'. The basaltic end-member comprises approximately 10-15% of the total bulk sediment and its presence is consistent with the local geology of source material in the drainage basin of the nearby Orange River. The increase in bulk accumulation at 2.4 Ma appears to reflect a greater relative increase in basaltic input than the relative increase in shale-type input. Although studies such as this cannot precisely identify the transport mechanisms of the different terrigenous components, these results are most consistent with variations in sea level (and associated changes in shelf geometry and fluvial input) being responsible for the changing depositional conditions along the Angolan Margin during this time period.

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Cite this as

Murray, Richard W, Christensen, Beth A, Kalbas, James L, Kryc, Kelly A (2002). Dataset: Major components and major and trace elements from ODP Site 175-1085. https://doi.org/10.1594/PANGAEA.744075

DOI retrieved: 2002

Additional Info

Field Value
Imported on November 30, 2024
Last update November 30, 2024
License CC-BY-3.0
Source https://doi.org/10.1594/PANGAEA.744075
Author Murray, Richard W
Given Name Richard W
Family Name Murray
More Authors
Christensen, Beth A
Kalbas, James L
Kryc, Kelly A
Source Creation 2002
Publication Year 2002
Resource Type application/zip - filename: Murray_2002
Subject Areas
Name: Lithosphere

Name: Oceans

Related Identifiers
Title: Pliocene export production and terrigenous provenance of the Southern Cape Basin, southwest African margin
Identifier: https://doi.org/10.1016/S0025-3227(01)00210-9
Type: DOI
Relation: IsSupplementTo
Year: 2002
Source: Marine Geology
Authors: Murray Richard W , Christensen Beth A , Kalbas James L , Kryc Kelly A .