Crustal structure and evolution of the Nicaraguan Rise from regional gravity, well, and seismic reflection data

Abstract

The Caribbean island of Jamaica (~11,500 km2) rises over 2.2 km above sea level at the eastern end of the much larger and shallowly submerged Nicaraguan Rise (~500,000 km2) in the western Caribbean. Upper Cretaceous to Miocene rocks exposed on land record a complex tectonic history that may have also affected the adjacent Nicaraguan Rise, is now submerged and covered by up to 2.5 km of shallow carbonate banks that form a challenging barrier for both seismic imaging and drilling. This study combines 10,000 km of 2D seismic reflection data, as well as 13 onshore and offshore wells with previous onland studies to define four tectonic phases affecting the Nicaraguan Rise that are compared to those events known from Jamaica. These events include: (1) Late Cretaceous to Paleocene arc-continent collision that resulted in transverse intra-arc rifting; these rifts are now exposed on land in a NW to SE orientation; (2) Paleocene-Eocene transtension that resulted in the formation of the Walton Basin at the boundary between the Nicaraguan Rise and Jamaica; this E—W basin is the deformed, eastern equivalent of the Honduran borderlands at the western end of the Nicaraguan Rise; (3) an Eocene to late Miocene post-rift thermal sag phase; this subsidence event followed the opening of the Cayman Trough and marks the beginning of widespread carbonate growth on the Nicaraguan Rise; and 3) late Miocene to Recent uplift and inversion related to E—W strike-slip faulting. Previous work has shown widespread Eocene type II and III source rocks of the Chapelton Formation of Jamaica and its offshore equivalents on the Nicaraguan Rise; that are immature where encountered in wells onland, but may be mature in the deeper buried areas of the Nicaraguan Rise, including the Walton Basin.

AAPG Datapages/Search and Discovery Article #90330©2018 AAPG Hedberg: Geology of Middle America – the Gulf of Mexico, Yucatan, Caribbean, Grenada and Tobago Basins and Their Margins “Integration of the geology of the area from the southern onshore of North America to the northern onshore of South America”, Siguenza, Guadalajara, Spain, July 2-5, 2018