Chemical labelling of oyster shells used for time-calibrated high-resolution Mg/Ca ratios: A tool for estimation of past seasonal temperature variations
The geochemical compositions of biogenic carbonates are increasingly used for palaeoenvironmental reconstructions. The skeletal δ18O temperature relationship is dependent on water salinity, so many recent studies have focused on the Mg/Ca and Sr/Ca ratios because those ratios in water do not change significantly on short time scales. Thus, those elemental ratios are considered to be good palaeotemperature proxies in many biominerals, although their use remains ambiguous in bivalve shells. Here, we present the high-resolution Mg/Ca ratios of two modern species of juvenile and adult oyster shells, Crassostrea gigas and Ostrea edulis. These specimens were grown in controlled conditions for over one year in two different locations. In situ monthly Mn-marking of the shells has been used for day calibration. The daily Mg/Ca ratios in the shell have been measured with an electron microprobe. The high frequency Mg/Ca variation of all specimens displays good synchronism with lunar cycles, suggesting that tides strongly influence the incorporation of Mg/Ca into the shells. Highly significant correlation coefficients (0.70
UPMC Univ Paris 06, UMR 7193 ISTeP, Laboratoire Biominéralisations et, Environnements Sédimentaires, Case postale 116, 4 place Jussieu, 75005 Paris, France; UPMC Univ Paris 06, CNRS FRE 3350, Laboratoire d'Ecogéochimie des Environnements Benthiques (LECOB), Observatoire Océanologique, av. du Fontaulé, 66650 Banyuls-sur-Mer, France; UPMC Univ Paris 06, Centre Camparis, 4, place Jussieu, 75005 Paris, France; Institut de Géologie et Paléontologie, Université de Lausanne, Anthropole, CH-1015 Lausanne, Switzerland
Recommended Citation:
Mouchi V.,de Rafélis M.,Lartaud F.,et al. Chemical labelling of oyster shells used for time-calibrated high-resolution Mg/Ca ratios: A tool for estimation of past seasonal temperature variations[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2013-01-01,373