Assertion: high mg calcite | /r/HasProperty | orthorhombic polymorph of caco
Facets:
Source sentences:
text: Since the beginning of the Paleozoic Era, there have been two intervals of “calcite seas,” in which nonskeletal carbonate precipitates from seawater have consisted of low-Mg calcite and three intervals of “aragonite seas,” in which these precipitates have consisted of high-Mg calcite or of aragonite, the orthorhombic polymorph of CaCO 3 (1) (Fig. 1).