Advancing planktonic foraminifera Mg/Ca thermometry: a microanalytical perspective

• Main Author: Sadekov, Aleksey Yu
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2011
• Subjects: Planktonic foraminifera
• Online Access: http://hdl.handle.net/1885/7155; https://digitalcollections.anu.edu.au/retrieve/31620/Sadekov-whole.pdf.jpg; https://digitalcollections.anu.edu.au/bitstream/1885/7155/1/Sadekov-front.pdf

Microanalytical techniques, specifically laser ablation - inductively coupled plasma mass spectrometry (LA-ICPMS) and electron microprobe analysis(EMPA), have been used to determine Mg/Ca compositional variation within and between tests of planktonic foraminifera. Micro-scale characterization of this increasingly widely-used seawater temperature proxy has allowed scrutiny of the factors that limit its applicability as well as the development of new microanalysis-based Mg/Ca proxy calibrations for sea surface temperature and thermocline temperatures.This study illustrates the potential for using novel microanalytical techniques to advance Mg/Ca thermometry, by both providing a framework for better understanding the nature of Mg/Ca dependence on seawater temperature and the effects of complicating factors (e.g. seafloor dissolution, seasonality), as well as providing insight into the underlying biomineralization mechanisms that control Mg incorporation into and the formation of foraminiferal calcite. Australian Research Council- via an ARC Discovery Grant DP0450358 to Prof. De Deckker and Dr. Eggins. The Australian National University by a tuition fee scholarship.