The Palaeozoic strata near Moeche in Galicia, NW Spain

Coral fragments, crinoidal debris and foraminifers found in limestone beds near Moeche (Galicia) are evidence of a Devonian-Silurian age for the strata in the greenschist facies belt around Cabo Ortegal, hitherto considered on the Spanish 1:200,000 map-La Coruña Hoja 1 (IGME), to be Precambrian in age. Their deposition by turbidity currents into troughs on an ancient ocean floor is being suggested

Calcium carbonate precipitation in the Cueva di Watapana on Bonaire, Netherlands Antilles

Calcium carbonate precipitates as low Mg-calcite and aragonite in slightly brackish water in a cave in the Pleistocene Middle Terrace of southern Bonaire. The calcium carbonate precipitates at the atmosphere-water interface forming floating calcite scales (calcite ice). Aragonite crystals frequently link the calcite scales together. The juxtaposition of calcite and aragonite is explained by calcite precipitation at the water-surface in nearly fresh water, with low Mg/Ca ratio, followed by the formation of aragonite near the bottom of the pool in more saline water with higher Mg/Ca ratio. The saline water with a higher magnesium content is most likely Caribbean sea water working its way inland through underground fissures