The Basal Complex of Jamaica, with special reference to the Kingston District

Publisher Website
Google Scholar
Abstract
I. I ntroduction . The Greater Antilles have had a complicated geological history, and much remains to be learned of the course of events, even in Tertiary times; but the pre-Tertiary history is especially obscure, and has been the subject of various changes of opinion. The older view was that throughout the Greater Antilles there lay, beneath a cover of Cretaceous and Tertiary sedimentary and volcanic deposits, an axis of ancient rocks which some authorities considered to be Archæan, others Palæozoic. The tendency of later work is to cast doubt on the antiquity of the older rocks, and to relegate many of them to the Cretaceous and Eocene Systems. The prevailing view now is that, in Jamaica, Porto Rico, and the Virgin Islands, there are no rocks older than Cretaceous, although they contain an igneous and metamorphic suite which in Cuba and Hispaniola is still regarded as pre-Cretaceous, and thought to range from Palæozoic to Jurassic. It is not surprising that discordant results have been reached in the several islands, when the difficulties of field investigation are considered. Throughout the Antilles the older rocks have been involved in intense mountain-making movements, vulcanicity, and igneous intrusions. The areas in which they occur are usually mountainous, intersected by deep gorges often clad with dense forest, and rarely provided with driving roads. The climate is tropical or sub-tropical, periods of heavy rainfall are prevalent, and tropical weathering has decomposed the strata for many feet below the surface. Finally, that all-important requirement of the field-geologist, an