ANTILLEAN-CARIBBEAN REGION 



fvSl 



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LOWER MIOCENE TO 

 LOWER EOCENE 



UPPER CRETACEOUS 



V - VOLCANIC ROCKS 

 S - SERPENTINE 



GRANODIORITE 



METAMORPHIC ROCKS 



NAUTICAL MILES 

 25 



Fig. 42.7. Geologic map of Jamaica. Shoreline and 2000-foot contour (clotted line) from World Aero- 

 nautical Chart No. 647. Geology adopted from Butterlin, 1956. Dotted contour line outlines Blue Mountains. 



Geology. Jamaica, like the other islands of the Greater Antilles, has 

 a basal complex in part older than Late Cretaceous. Three cycles of 

 deposition followed the basal complex, each with a sequence of conglom- 

 erate, sand, shale, mudstone, calcareous shale, and limestone, and each 

 separated by an unconformity ( Butterlin, 1956 ) . The third cycle ended in 

 early Eocene with intense deformation and intrusions. Thrusting has been 

 noticed and is assigned to this time. 



The Yellow limestone of mid-Eocene age was then deposited. White 

 limestone accumulation continued to mid-Miocene time when block- 

 faulting occurred. The faults trend generally north-northwest or north- 



west, and rejuvenate in places the earlier structures. Extrusions of lavas 

 also occurred. 



During the Pliocene, block faulting continued and raised up the cal- 

 careous tablelands and in places tilted them. The Cayman Islands across 

 the trench were possibly connected with Jamaica before the block faulting 

 (Butterlin, 1956). 



Virgin Islands and Anegada Trough 



A bank not more than 165 feet deep extends 100 miles eastward from 



Puerto Rico like a crescent curving northward. From this bank rise about 



