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Beryllium, thorium and protactinium isotope ratios in sediments from the Galapagos microplate

Biogenic particle fluxes from highly productive surface waters, boundary scavenging, and hydrothermal activity are the main factors influencing the deposition of radionuclides in the area of the Galapagos microplate, eastern Equatorial Pacific. In order to evaluate the importance of these three processes throughout the last 100 kyr, concentrations of the radionuclides 10Be, 230Th, and 231Pa, and of Mn and Fe were measured at high resolution in sediment samples from two gravity cores KLH 068 and KLH 093. High biological productivity in the surface waters overlying the investigated area has led to 10Be and 231Pa fluxes exceeding production during at least the last 30 kyr and probably the last 100 kyr. However, during periods of high productivity at the up welling centers off Peru and extension of the equatorial high-productivity zone, a relative loss of 10Be and 231Pa may have occurred in these sediment cores because of boundary scavenging. The effects of hydrothermal activity were investigated by comparing the 230Thex concentrations to the Mn/Fe ratios and by comparing the fluxes of 230Th and 10Be which exceed production. The results suggest an enhanced hydrothermal influence during isotope stages 4 and 5 and to a lesser extent during isotope stage 1 in core KLH 093. During isotope stages 2 and 3, the hydrothermal supply of Mn was deposited elsewhere, probably because of changes in current regime or deep water oxygenation. A strong increase of the Mn/Fe ratio at the beginning of climatic stage 1 which is not accompanied by an increase of the 230Thex concentration is interpreted to be an effect of Mn remobilization and reprecipitation in the sediment.

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Cite this as

Frank, Martin, Eckhardt, Joerg-Detlef, Eisenhauer, Anton, Kubik, Peter W, Dittrich-Hannen, Beate, Segl, Monika, Mangini, Augusto (1994). Dataset: Beryllium, thorium and protactinium isotope ratios in sediments from the Galapagos microplate. https://doi.org/10.1594/PANGAEA.726083

DOI retrieved: 1994

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.726083
Author Frank, Martin
Given Name Martin
Family Name Frank
More Authors
Eckhardt, Joerg-Detlef
Eisenhauer, Anton
Kubik, Peter W
Dittrich-Hannen, Beate
Segl, Monika
Mangini, Augusto
Source Creation 1994
Publication Year 1994
Resource Type application/zip - filename: Frank_1994
Subject Areas
Name: Lithosphere

Name: Oceans

Name: Paleontology

Related Identifiers
Title: Beryllium 10, thorium 230, and protactinium 231 in Galapagos microplate sediments: Implications of hydrothermal activity and paleoproductivity changes during the last 100,000 years
Identifier: https://doi.org/10.1029/94PA01132
Type: DOI
Relation: IsSupplementTo
Year: 1994
Source: Paleoceanography
Authors: Frank Martin , Eckhardt Joerg-Detlef , Eisenhauer Anton , Kubik Peter W , Dittrich-Hannen Beate , Segl Monika , Mangini Augusto .