Structural Relations Among Lesser Antilles, Venezuela, and Trinidad-Tobago

Abstract

More than 2,500 n. mi (4,630 km) of seismic reflection profiling, gravity, magnetics, and bathymetric data were collected in the southeastern Caribbean by the ESSA Coast and Geodetic Survey ship Discoverer in 1968-1969. A review of the structural geology of the southeastern Caribbean and the South American continent in conjunction with the ESSA data supports a relatively simplistic explanation for the geologic structure. The Barbados Ridge is a greatly fractured anticlinorium, supported by basement rocks, and consisting of two parallel arches with a central syncline. The Lesser Antilles volcanic arc, the Tobago trough, and the Barbados anticlinorium are traceable into the Venezuelan and Trinidadian shelves (South American continent). An analogy between the Caribbean and Indonesian island arcs shows the validity of the concept of continuation of continental mobile belts into island arc systems. The mobile belt and the island arc system are analogous manifestations of orogeny in different crustal types. Evidence is against wrench faulting, with its implication of vast horizontal movements of individual blocks. The island arc structural belts and the mobile belts of the continent are interrelated, gradational, and interlocked.