Abstract Previous workers, mainly mapping on-land active faults on Caribbean islands, defined the northern Caribbean plate boundary zone as a 200-km-wide and bounded by two active and parallel strike-slip faults: the Oriente fault along the northern edge of the Cayman trough having a GPS rate of 14 mm/yr, and the Enriquillo-Plaintain Garden fault zone (EPGFZ) having a rate of 5-7 mm/yr. In this study, we used 5,000 km of industry and academic data from the Nicaraguan Rise south and southwest of the EPGFZ in the maritime areas of Jamaica, Honduras, and Colombia to define an offshore, 700-km-long, active, left-lateral strike-slip fault in what had been considered previously the stable interior of the Caribbean plate as determined from plate-wide GPS studies. The fault was named by previous workers as the Pedro Banks fault zone (PBFZ) because a 100-km-long segment of the fault forms an escarpment along the Pedro carbonate bank of the Nica-raguan Rise. Two fault segments of the PBFZ are defined: the 400-km-long eastern segment that exhibits large negative flower structures 10-50 km in width; fault segments rupture the sea floor as defined by high resolution 2D seismic data; and a 300-km-long western segment that is defined by a narrow zone of anomalous seismicity first observed by previous workers. The western end of the PBFZ terminates on a Quaternary rift structure, the San Andres rift, associated with Plio-Pleistocene volcanism and thickening trends indicating initial rifting in the late Miocene. The southern end of the San Andreas rift terminates on the western Hess fault which also exhibits active strands consistent with left-lateral, strike-slip faults. The total length of the PBFZ-San Andres rift-Southern Hess escarpment fault is 1,200 km and traverses the entire western end of the Caribbean plate. Our interpretation is similar to previous models that have proposed the “stable” western Caribbean plate is broken by this fault, the rate of displacement of which is less than the threshold recognizable from the current GPS network (~3 mm/yr). The late Miocene age of the fault indicates it may have activated during the late Miocene to recent His-paniola-Bahamas oblique collision event.

Without a resident population of informed experts, the study of the geology of Jamaica during the nineteenth century relied upon visits by peripatetic specialists. Such visitors were rare, coming about every 35 years or so: H.T. De la Beche (mid–1820s), Lucas Barrett and J.G. Sawkins (1860s), and R.T. Hill (late 1890s). The theory and practice of geology had moved on with every visit. In the 1920s and 1930s, with improved international travel, geologists were more common visitors. C.A. Matley, of the second geological survey of the island, and C.T. Trechmann, a wealthy amateur, sought data that supported their conflicting theories of Jamaica's geological evolution, although their primary interests were field mapping and paleontology, respectively. At the same time, W.P. Woodring described the diverse mollusks of the Bowden shell bed, a key biostratigraphic horizon in the Antillean Neogene, without actually visiting the island until much later. Following the Second World War, the foundation of the modern Geological Survey Department based in Kingston encouraged new field studies, under the leadership of V.A. Zans and L.J. Chubb. Following Draper's model, the geological evolution of the island is considered to have involved four phases: island arc volcanism during much of the Cretaceous; early Paleogene uplift and intrusion; mid-Cenozoic quiescence and limestone deposition; and late Cenozoic tectonic revival. This framework relies on a plate tectonic synthesis which was only formulated after the death or retirement from active research of the geologists that form the focus of this volume.

ABSTRACT (S.K. Donovan) Henry Thomas De la Beche (1796–1855) was one of a distinguished group of gentleman geologists whose activities and abilities inspired and drove the Geological Society in London in the first half of the nineteenth century. De la Beche, both a devoted field geologist and, later, an expert administrator, is best remembered for his contribution as the first director of the first national geological survey, that of Great Britain. De la Beche was also the first Antillean geologist, visiting Jamaica for a year in 1823–1824 to inspect his family estate at Halse Hall, parish of Clarendon. In Jamaica, De la Beche made a geological map of the eastern half of the island, a tremendous achievement for one man in 12 months; the principal features of this map are still recognizable to the modern geologist. De la Beche identified the main lithological divisions of the Jamaican rock record; his white limestone formation is still current, as the White Limestone Group, for the most extensive lithological unit on the island. De la Beche's correlation of the lower part of this formation (= Yellow Limestone Group of modern usage), containing giant Cerithium snails (= Campanile trevorjacksoni Portell and Donovan, 2008), with European successions containing similar fossils was the earliest example of intercontinental biostratigraphic correlation. His intercontinental lithostratigraphic correlations were erroneous, but accepted at a time when the value of biostratigraphy was poorly understood. In particular, his recognition of many pre-Cretaceous deposits was a glaring, if understandable, error based on De la Beche's correlations which relied on lithostratigraphic similarities between European and Jamaican formations.