ABSTRACT
The Lucea Inlier exposes a Santonian to Campanian 4 km + thick sequence of shale-siltstone, resedimented volcaniclastics, lenses of shallow-water limestone, micritic limestone, pebbly mudstone and sandy pebble to boulder conglomerate. Clastics were deposited by a variety of gravity flow mechanisms. Petrographically sandstones are lithic or feldspathic arenites and contain only very small amounts of detrital quartz. Structurally the inlier is characterized by simple, open, east-west trending folds. A spaced, vertical axial-planar cleavage is developed in shales and fine siltstones. Two major east-west trending left-lateral fault zones, the Fat Hog Quarter and Maryland faults, cut the inlier into three blocks, northern, central and southern. The basal part of the sequence has been subjected to a prehnite-pumpellyite metamorphism.
The rocks of the Lucea Inlier are interpreted to represent a shelf to basin sequence within an upper slope basin of a Cretaceous intraoceanic arc trench system. Detritus shed from the arc was funneled down submarine canyons feeding a submarine fan complex. Between canyon heads, shoal areas fringing volcanic islands locally accumulated bioclastic, reef-type limestone.
The geology of the northern Caribbean plate boundary records a complex array of Cretaceous to Eocene arc-trench systems that has been modified by Cenozoic left-lateral slip along the Oriente and Swan transforms.
Ridge related north-south lineated topography of the Cayman Trough suggests that a minimum of 720 km of left-lateral movement has occurred between the North American and Caribbean plate since approximately Oligocene times. Presently active northwest, northeast and east-west trending structures within Jamaica are interpreted as being of compressional, extensional and strike-slip origin, respectively, and are thought to be related to Recent left-lateral slip along the northern Caribbean plate boundary.

Grippi, J., 1978. Geology of the Lucea Inlier, Western Jamaica. Unpublished MSc. thesis, State University of New York at Albany.
183pp., +x.; 6 folded plates (maps)
University at Albany Science Library call number:  SCIENCE Oversize (*) QE 224 G63X

Return to MS Theses completed in the Geological Sciences Program, University at Albany