Distribución de Mg en conchas de Crassostrea gigas : control microestructural y correlaciones cristaloquímicas

Abstract

The realization of geochemical studies on the right valve of Crassostrea gigas's shells has allowed demonstrating a microestructural control on the concentration of Mg. The transects studied in this work show that the ratio Mg/Ca is higher in the Prismatic (SP) and Chalk microstructures than in the Regular Foliated (RF) one. Fhe faster precipitation of SP and Chalk could be the reason for the behaviour of the Mg.

Fhe unit cell parameters of the principal microstructures in a C. gigas valve have been determined, looking for good correlation between the content of Mg (ppm) and the volume of the unit cell. Fhe presence of Mg2+ (ionic radius=0.65 A) instead ofCa2+ (ionic radius=0.99 A), generate an important lattice distortion along the c-axis, allowing the presence ofanother cations, such as Na+(ionic radius=0.96 A).