Magnesium/Calcium ratios in benthic foraminifera from surface sediments ...
We used modern epibenthic foraminifer tests of Cibicidoides mundulus and Planulina wuellerstorfi from South Atlantic core top sediments in order to establish Mg/Ca-temperature relationships for the temperature range from 0 to 15°C. We obtained the following calibrations: Mg/Ca (mmol/mol) = 0.830*exp...
Main Authors: | , , , |
---|---|
Format: | Dataset |
Language: | English |
Published: |
PANGAEA
2008
|
Subjects: | |
Online Access: | https://dx.doi.org/10.1594/pangaea.759564 https://doi.pangaea.de/10.1594/PANGAEA.759564 |
Summary: | We used modern epibenthic foraminifer tests of Cibicidoides mundulus and Planulina wuellerstorfi from South Atlantic core top sediments in order to establish Mg/Ca-temperature relationships for the temperature range from 0 to 15°C. We obtained the following calibrations: Mg/Ca (mmol/mol) = 0.830*exp(0.145*BWT (°C)) for P. wuellerstorfi, and Mg/Ca (mmol/mol) = 0.627*exp(0.143*BWT (°C)) for C. mundulus. However, a number of tests, especially those bathed in North Atlantic Deep Water, revealed higher Mg/Ca ratios than predicted from the calibration. Our data suggest that d[CO3 2-] of bottom water exerts a significant control on dMg/Ca (temperature-corrected) of C. mundulus (dMg/Ca = 0.017*d[CO3 2-] -0.14), while dMg/Ca of P. wuellerstorfi is more likely to be governed by TCO2 (dMg/Ca = -0.007*TCO2 + 15). Since both d[CO3 2-] and TCO2 are closely linked to [CO3 2-], it is inferred that carbonate ion acts as secondary control, after temperature, on benthic shell Mg/Ca below -4°C. A drop in [CO3 2-] by 25 ?mol/kg ... : Supplement to: Raitzsch, Markus; Kuhnert, Henning; Groeneveld, Jeroen; Bickert, Torsten (2008): Benthic foraminifer Mg/Ca anomalies in South Atlantic core top sediments and their implications for paleothermometry. Geochemistry, Geophysics, Geosystems, 9(5), Q05010 ... |
---|