Clay mineral sources of the Grenada Basin, southeastern Caribbean

ABSTRACT: This study of the Quaternary clay sedimentation i the Grenada Basin (Southeastern Caribbean) is based on six cores raised from depths of 1800 to 3000 m. Mineralogical analysis of <2 #m and <0-3 #m fractions revealed the presence of a four-component association-- smectites, illite, kaolinite and chlorite-- in which smectites were always dominant. These minerals were derived from two sources: the Lesser Antilles Arc, which contributed only smectites and kaolinite, and the South American continent, where smectites, kaolinite, chlorite and illite coexist. Geochemical data indicate that Ba and Cr are specific indicators of the South American minerals, whereas Cu characterizes the Antillean clays. The South American contribution, now prevailing, was less important during the Sangamon. The Antillean contribution was episodically predominant during the Wisconsin. The Quaternary clay mineral assemblage of the Grenada Basin consists of four components-- smectites, illite, kaolinite and chlorite-- which are known to be derived from two sources: the Lesser Antilles Arc, which contributes only smectites and kaolinite, and the South American continent where smectites, illite, kaolinite and chlorite coexist (Pautrizel, 1982). The purpose of the present study was to compare the trace-element compositions of the clay minerals with those of the source area minerals with the aim of estimating the relativ