DETAILED STRATIGRAPHY OF UPPER JURASSIC SEDIMENTARY AND VOLCANOCLASTIC ROCKS FROM WESTERN PANGEA OUTCROPPING ALONG THE PROTO CARIBBEAN

The breakup of Supercontinent Pangea resulted in several extensional basins along the Proto-Caribbean region. The Lower Jurassic to Lower Cretaceous sedimentary record of these basins display predominantly basal continental environments which grade upward to marine environments. This transition in depositional environments has been interpreted as the result of a widespread rapid sea level rise along the Proto Caribbean. However, in the Northern most Andes, continental red beds and volcanic rocks display a lateral variation to marine shales that suggest a continuous continental-marine depositional profile and do not necessarily represent sea level variations. Here we present detailed sedimentological and stratigraphic information from Jurassic sedimentary successions that crop out to the south (Perija Range) and to the north of Oca Fault (Cosinas Range, Alta Guajira Basin). While Jurassic sedimentary rocks from the Perija Range mostly consists of volcanic, volcaniclastic and redbeds rocks (La Quinta Formation), the Jurassic sedimentary record in the NE Cosinas Range is instead dominated by marine shales and carbonates (Cosinas Group), and in the SW Cosinas Range displays the transition from the redbeds and volcanic rocks trough the marine rocks (Rancho Grande Formation and Uitpana Formation, respectively). We conclude that Jurassic-Cretaceous sedimentary record of the Northernmost Andes were deposited along a single extensional basin during the Pangea break-up, and that the lateral variations of facies are not related to the changes of eustatic sea level changes.