Date of Award
Master of Science (MS)
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, Jack, "Geology of the Lucea Inlier, Western Jamaica" (1978). Geology Theses and Dissertations. 31.
Plate 1 - Geologic Map - Lucea Inlier, Western Jamaica (uncoloured geological map; scale 1:15,840)
grippipl1a.pdf (728 kB)
Plate 1A - Stratigraphic columns of the Central Block - Lucea Inlier, Western Jamaica (scale 1:2500)
grippipl1b.pdf (366 kB)
Plate 1B - Geologic cross sections - Lucea Inlier, Western Jamaica (uncoloured; scale 1:15,840)
grippipl2.pdf (2533 kB)
Plate 2 - Geologic Map - Cascade-Maryland area - Lucea Inlier, Western Jamaica (uncoloured geological map; scale 1:12,500)
grippipl2a.pdf (406 kB)
Plate 2A - Stratigraphic columns of the Cash Hill Anticline - Lucea Inlier, Western Jamaica (scale 1:3000)
grippipl2b.pdf (551 kB)
Plate 2B - Geologic cross sections - Cascade-Maryland area - Lucea Inlier, Western Jamaica (uncoloured; scale 1:12,500)