High resolution distribution of magnesium and strontium and the evaluation of Mg/Ca thermometry in recent brachiopod shells

Perez-Huerta, A., Cusack, M. , Jeffries, T. and Williams, C.T. (2008) High resolution distribution of magnesium and strontium and the evaluation of Mg/Ca thermometry in recent brachiopod shells. Chemical Geology, 247(1-2), pp. 229-241. (doi: 10.1016/j.chemgeo.2007.10.014)

Abstract

High resolution distribution of magnesium and strontium determined by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry (LA-ICP-MS) are presented in this study for Recent brachiopod shells. The concentration of magnesium and strontium decreases in a similar fashion from the outer to inner regions of shells of rhynchonelliform species but remains unaltered in craniid brachiopods. In rhynchonelliform brachiopods with low-magnesium shells, there is a characteristic chemical profile with an abrupt decrease in magnesium concentration from the primary layer towards the secondary layer until it reaches a region in which the values are almost constant. In addition, there is a proportional relationship in magnesium concentration between primary and secondary layers. Both findings demonstrate the biological control in magnesium incorporation in rhynchonelliform brachiopods confirming previously reported findings. Calculated Mg/Ca ratios based on magnesium concentrations within the innermost region of the secondary layer show that rhynchonelliform brachiopods can record seawater temperature. This finding opens up the possibility of using Mg/Ca (palaeo) thermometry even within the context of biological control and the potential application of Mg/Ca ratios as a seawater temperature proxy in fossil brachiopods.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Cusack, Professor Maggie and Perez-Huerta, Dr Alberto
• Authors: Perez-Huerta, A., Cusack, M., Jeffries, T., and Williams, C.T.
• Subjects: Q Science > QH Natural history > QH345 Biochemistry; Q Science > QH Natural history
• College/School: College of Science and Engineering > School of Geographical and Earth Sciences
• Journal Name: Chemical Geology
• ISSN: 0009-2541
• ISSN (Online): 1872-6836
• Published Online: 04 November 2007