DISTRIBUTION OF FORAMINIFERS IN THE CABO ROJO PLATFORM AND THEIR PALEOECOLOGICAL SIGNIFICANCE

摘要

Eighty seven sediment samples were taken from the Cabo Rojo platform, southwestern Puerto Rico, to study the sediments, mineralogy and foraminifers. This part deals with the foraminifers and their distribution. Glauconitized foraminifers were found in four different facies: beach, back-reef, middle reef basin, and middle to outer shelf glauconite facies. The Glauconitized foraminifers are characteris¬tic of the middle and rear part of the reef. Foraminifers with carbonized or pyritized protoplasm occur only in muddy sediments. None of the muddy bottom foraminifers were glauconitized and no reef foraminifer was carbonized or pyritized. Glauconite is formed in a different environment than pyrite. Five foraminiferal facies were determined: beach, back-reef bay, reef flat, middle reef basin and reef talus and middle to outer shelf facies. The reef flat facies is subdivided in northern and southern sub-facies.