Abstract

The Sans Souci Formation of northeastern Trinidad is a sequence of basaltic clastic rocks and lavas, gabbros and terrigenous sedimentary rocks at the eastern end of the Caribbean Mountain orogen. A distinctive clastic character to many of the igneous rocks suggests a process of thermal erosion after internal brecciation of thick submarine lava flows and shallow intrusions. The tholeiites of the Sans Souci Formation were erupted on to the passive continental margin of northern South America during the interval Aptian–Santonian. The associated sedimentary rocks are limestones, shales, sandstones and conglomerates with a continental provenance. Chemically, the Sans Souci lavas have MORB affinities which distinguish them from the island arc tholeiites found on neighbouring Tobago. The Los Naranjos member of the Tucutenemo Formation of central Venezuela is probably the metamorphic equivalent of the Sans Souci Formation. A speculative source for these volcanic rocks is a period of mid-Cretaceous intraplate flood basalt volcanism. This appears to have occurred both to the north and to the south of the island arc which collided with the continental margin in the late Cretaceous.

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