Title of article :
Mg/Ca variation in planktonic foraminifera tests: implications for reconstructing palaeo-seawater temperature and habitat migration
Author/Authors :
Eggins، نويسنده , , Stephen and De Deckker، نويسنده , , Patrick and Marshall، نويسنده , , John، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2003
Pages :
16
From page :
291
To page :
306
Abstract :
The nature of compositional variability within the tiny calcitic shells (tests) that are precipitated by planktonic foraminifera has been investigated using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Systematic large and correlated variation of Mg/Ca, Mn/Ca, Ba/Ca and Zn/Ca but relatively uniform Sr/Ca are observed through the test walls of analysed species (Globigerinoides sacculifer, Globigerinoides ruber, Neogloboquadrina pachyderma and Neogloboquadrina dutertrei). Distinct chamber and chamber-wall layer compositions can be resolved within individual tests, and Mg/Ca compositional differences observed in sequentially precipitated test components of the different species analysed are consistent with seawater temperature changes occurring with habitat migration during their adult life-cycle stages. Estimated test calcification temperatures are in keeping with available seawater temperature constraints, indicating the potential for accurate seawater temperature reconstruction using LA-ICP-MS. Mg-rich (<1–6 mol% Mg) surface veneers that are also enriched in Mn, Ba, and Zn have been found on all species and all fossil tests, as well as on live-sampled tests of G. ruber, with the latter suggesting a possible biogenic origin. These Mg-rich surfaces bias bulk test compositions toward higher Mg/Ca values by between 5 and 35%.
Keywords :
laser ablation ICP-MS , planktonic foraminifera , palaeoceanography , Trace elements , Mg/Ca seawater thermometry
Journal title :
Earth and Planetary Science Letters
Serial Year :
2003
Journal title :
Earth and Planetary Science Letters
Record number :
2322954
Link To Document :
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