Geologic maps of the southwestern Puerto Rico Parguera to Guanica insular shelf
These maps describe the sediments and sedimentary environment of the southwestern Puerto Rico shelf (index). In addition to presenting new data, the maps summarize earlier geological investigations. There are two morphological zones separated along a line extending southward from Punta Jorobaflo. The Parguera shelf extends from this line to the western boundary of the study area, and the Guanica shelf extends from Punta Jorobado to the eastern study limit (fig. 1). The age and character of the underlying limestone bedrock, the depositional environment, the history of subaerial erosion, and the intensity of modem physical processes differ in each of these shelf areas. However, the bedrock surface of both the Parquera and Guanica shelves is primarily karst; the limestone surface was modified by reef growth and sediment deposition after the last glacial lowstand. Although several anticlines and faults that trend parallel to the shoreline have been mapped on the adjacent land areas (Volckmann, 1984), no evidence was found to suggest major structural features on the shelf.