SEDIMENT MINERALOGY IN THE BAY-OF-HAVANA (CUBA) - ITS RELATION TO NATURAL AND ANTHROPOGENIC PROCESSES

The mineralogical analysis by means of X-ray diffraction of the surfic ial sediments from the Bay of Havana (Cuba) allows us to identify and quantify the presence of quartz, feldspars, calcite, magnesium calcite , aragonite and dolomite. The distribution of these minerals permits u s to distinguish the occurrence of five sedimentary environments (coas tal marine, transitional bay-marine, bay, prodelta and Luyano Drain en vironments) and relate them to the general trends of sedimentary dynam ics in the bay. The mineralogy of the coastal marine sediments is domi nated by the composition of the local calcareous substratum, i.e., by magnesium calcite and dolomite. These minerals are associated with ara gonite in the transitional environment existing between the marine and the bay environments. The sediments in the bay show high contents of aragonite and calcite, while quartz and feldspars are in important qua ntities in the sediments from the prodelta environments. These mineral ogical features are consistent with the natural processes occurring in the Bay of Havana, while the composition of the sediments from the Lu yano Drain environment seem affected by the anthropogenic supply of th is drain, showing very high contents of calcitic biogenic products.