Relationships between the distribution of Amphistegina and the submerged Pleistocene reefs off western Puerto Rico

Seiglie, G.A.

Tulane Studies in Geology 6(4): 139-147


More than 100 samples were taken from Holocene and Pleistocene reef sediments in an area of about 12 by 11 km. Pleistocene reef remnants submerged to 80 m depth and a wave-cut terrace at 55 m depth were found with five echo-sounding profiles. Three main foraminiferal reef assemblages exist today in the Caribbean region: the Amphistegina-Archaias fauna in the warm waters of the Antilles (including study area), and two Amphistegina (without Archaias) faunas, one in the Gulf of Mexico, the other off eastern Venezuela, in less warm waters. The submerged Pleistocene reefs are correlated with those in the Gulf of Mexico and off Barbados. The highest percentages of Amphistegina gibbosa, both Pleistocene and modern, are associated with the position of submerged Pleistocene reefs in these areas.