A STUDY OF DOLOMITES IN ISLA DE MONITO

Isla de Monito is a carbonate island situated in the Caribbean Sea (South-central Mona Passage), between Puerto Rico and Hispaniola Island (Kaye, 1959). Abundant studies on dolomite (mineral), dolostone and dolomitization are available for the Bahamas limestones and the rest of the Caribbean (Vahrenkamp and Swart, 1994; Land, 1973; Mitchell et al., 1987; Machel, 2000; Ward and Halley, 1985); however a few data are available for the archipelagos of Puerto Rico in dolomite studies (Gonzalez et al., 1997; Ramírez, 2000). The profuse dolomite deposits in the limestones of Isla de Monito, Puerto Rico, have not been studied. The difficult access to the island makes it a remote place to visit and do research in the island permits by DRNA are required. Isla de Monito provides a perfect environment to study diagenesis and dolomitization processes in limestones since no terrigenous sediments are present in the area. The lithology and stratigraphy of Isla de Monito can be correlated in many aspects to Isla de Mona Dolomite. Isotopic signatures were consistent with a mixing zone environment. An equivalent to The Lirio Limestone was not found in Isla de Monito. The island is the result of a combination of a variety post depositional alterations that resulted in the development of different types of dolomite fabrics and textures in a mixing zone environments. The similarities and differences between both islands (Isla de Monito and Isla de Mona), are discussed from the stratigraphic, petrographic and geochemical point of view.