ABSTRACT

Mineral compositions have long been used as indicators of the provenance and tectonic setting of source rocks for sandstones and shales. Extraction of the same information from limestones is less common because of the general paucity of the non-carbonate phase and the greater processing time that is required to concentrate the small quantities of detrital (and authigenic) minerals usually encountered. The insoluble component, however, contains a great deal of information and should not be ignored. The clays and other insoluble minerals in limestones from southeastern United States and the Caribbean region clearly reflect volcanic and tectonic activity that was taking place in the Caribbean and Gulf of Mexico. Similarly, major periods of uplift and orogeny during the Paleozoic and Mesozoic have left their signature, even in carbonate rocks that originated far from sites where uplift was taking place. In other cases, the insoluble residue component clearly reflects periods of quiescence in adjacent land areas or to the airborne transport of insoluble components from sources as far distant as the Saharan Desert of Africa. Further, insoluble residue analyses have convincingly shown that the thick bauxite deposits found on Jamaican limestones are the result of alteration of interbedded volcanic ash units and have not resulted from accumulation of the detritus in the limestones. Conversely, similar analyses from the Yucatan Peninsula of Mexico confirm that the terra rosa soils of that region have formed by accumulation and transformation of insoluble residues from the underlying limestones.