Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

Encrustation and trace element composition of Neogloboquadrina dutertrei assessed from single chamber analyses - implications for paleotemperature estimates

Jonkers, Lukas, De Nooijer, L. J., Reichart,, G.-J., Zahn, R. and Brummer, G.-J. A. 2012. Encrustation and trace element composition of Neogloboquadrina dutertrei assessed from single chamber analyses - implications for paleotemperature estimates. Biogeosciences 9 (11) , pp. 4851-4860. 10.5194/bg-9-4851-2012

[img]
Preview
PDF - Published Version
Available under License Creative Commons Attribution.

Download (2MB) | Preview

Abstract

Abstract. Crust formation is a common phenomenon in planktonic foraminifera. Because of their different formation mechanism and hence composition, crusts affect the overall test composition and therefore complicate the use of crust-bearing foraminifera in paleoceanography. Such species are often used to estimate subsurface paleotemperatures, and although the influence of encrustation on the trace element/Ca ratio is recognised, it has not been systematically explored between and within tests. Here we use laser ablation ICP-MS to assess the variability in trace element composition of the crust of Neogloboquadrina dutertrei within individual chambers, as well as the effect of compositional heterogeneity of the crust on whole test chemistry. Compositionally, the outer crust differs from inner layer by lower Mg/Ca and Mn/Ca, but is indistinguishable in Sr/Ca. Crust thickness decreases towards the younger chambers, and it may be entirely absent from the last chamber. In contrast to Mn/Ca and Sr/Ca, crustal Mg/Ca ratios show a tendency towards higher values on the younger chambers. These patterns in crust thickness and in crust Mg/Ca indicate that temperature is not the dominant factor controlling crust composition. Temperature estimates based on N. dutertrei, and presumably other crust-forming species too, are therefore biased towards too low values. Through comparison of modern and glacial tests, we show that this bias is not constant and that changes in crust thickness and/or in Mg/Ca values can spuriously suggest temperature changes.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Earth and Ocean Sciences
Subjects: G Geography. Anthropology. Recreation > GC Oceanography
Publisher: Copernicus Publications
ISSN: 1726-4170
Date of First Compliant Deposit: 30 March 2016
Last Modified: 22 Oct 2016 03:19
URI: http://orca.cf.ac.uk/id/eprint/42374

Citation Data

Cited 9 times in Google Scholar. View in Google Scholar

Cited 20 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics