Distribution of Planktonic Foraminifera in Surface Sediments of the Gulf of Mexico

Abstract

Frequency distributions of planktonic foraminifera from 140 trigger core-tops in the Gulf of Mexico generally reflect major oceanographic features. The distribution of Globigerinoides sacculifer outlines the Loop Current in the eastern Gulf and Globigerinoides ruber maxima marks salinity extremes, whereas the distributions of Pulleniatina obliquiloculata, Globorotalia truncatulinoides and Globigerinita glutinata parallel winter isotherms in the Gulf. Q-mode factor analysis was used to extract 5 assemblages from 23 species and compare their distributions in the Gulf to those of the well-studied Atlantic Ocean. The 5 assemblages are interpreted as: 1) subtropical, dominated by G. ruber; 2) temperate, composed of Globorotalia inflata, Globigerina falconensis, Globorotalia truncatulinoides, Globigerina buloides and Neogloboguadrina dutertrei; 3) dissolution-resistant, consisting of Globorotalia menardii, Pulleniatina obliquiloculata and N. dutertrei; 4) equatorial, composed of G. sacculifer and P. obliquiloculata; and 5) subpolar, consisting of N. dutertrei, G. inflata, Neogloboguadrina pachyderma and G. bulloides. The modern distributions of these assemblages have been used to develop 4 transfer functions from which the winter and summer temperatures and salinities for the Late Quaternary have been estimated. Distribution of planktonic foraminifera in surface sediments of the Gulf of Mexico