Characterization of contaminant phases in foraminifera carbonates by electron microprobe mapping

Pena, L.D. and Cacho, I. and Calvo, E. and Pelejero, C. and Eggins, S. and Sadekov, A. (2008) Characterization of contaminant phases in foraminifera carbonates by electron microprobe mapping. Geochemistry Geophysics Geosystems, 9 (7). DOI 10.1029/2008GC002018

[img] PDF
3_G_2008GC002018.pdf
Restricted to Registered users only

Download (1MB)
Official URL: http://www.scopus.com/inward/record.url?eid=2-s2.0...

Abstract

The advent of new microanalytical techniques such as electron microprobe mapping (EMP) and laser ablation microsamplers coupled to mass spectrometers (LA-ICP-MS) provides a new array of possibilities to explore in great detail the trace elements distribution in foraminiferal carbonates. Here we apply these techniques to characterize diagenetic phases present in foraminiferal shells from Ocean Drilling Program Site 1240 in the Panama Basin, a region characterized by the presence of manganese-rich minerals in the sediments. The combined application of these techniques allows us to characterize the elemental and spatial distribution on the surface and across the foraminiferal shells. Results illustrate the presence of at least two different Mn-rich contaminant phases in the foraminiferal carbonates: Mn-rich carbonates and ferromanganese oxides. Elemental maps also highlight the relevance of the foraminifera shell texture and porosity in the distribution and formation of these contaminant phases. In the case of Neogloboquadrina dutertrei, Mn phases form a continuous thin layer in the inner part of the chambers, whereas for Globigerinoides ruber, Mn phases have a rather patchy distribution and are usually found within the pores. Significant high magnesium concentrations are always associated with these Mn-rich phases. These new findings support the need of removing these Mn-rich contaminant phases in order to measure accurately the Mg/Ca ratios in the foraminifera shell and therefore obtain reliable Mg/Ca paleotemperature reconstructions. Copyright 2008 by the American Geophysical Union.

Item Type: Article
Uncontrolled Keywords: NILAREP
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Geochemistry Geophysics Geosystems
Volume: 9
Identification Number: 10.1029/2008GC002018
Depositing User: Sarah Humbert
Date Deposited: 02 Apr 2012 11:27
Last Modified: 23 Jul 2013 10:03
URI: http://eprints.esc.cam.ac.uk/id/eprint/2438

Actions (login required)

View Item View Item

About cookies