The vanishing Carib Halite Formation (Neocomian), Colombia-Venezuela-Trinidad prolific petroleum province

Abstract

Abstract Literature survey reveals evidence of a thick ( c . 3 km), largely dissolved, Berriasian–Valanginian ‘Carib Halite Formation’, deposited in a Jurassic to Coniacian ‘Carib Graben’ from Colombia through Venezuela to Trinidad. From Campanian time the graben inverted into the (partly metamorphosed) south-verging nappe/thrust-belt of northern South America (Guajira to Trinidad), and later the bivergent Eastern Cordillera and Mérida Andes. Outcropping halite is confined to Colombia. Numerous lines of evidence suggest buried halite in Colombia, Venezuela and Trinidad: drowning coastal geomorphology (halite-solution subsidence); subaerial and submarine closed depressions (solution pits); saline springs; mud-volcano-fluid analysis; heat-flow anomalies; gravity anomalies; and thrust-belt structural style. Other data suggest thick (kilometres) vanished halite: a Berriasian regional faunal gap; highly organic shales/phyllites (solution residues); intense fracturing (solution collapse); metamorphic-grade discontinuities (solution weld); and Neogene supraorogen basins attributable to buried-halite solution, for example Gulf of Venezuela, Monagas thrust belt, Gulf of Paria and onshore Trinidad. Halite solution by circulating meteoric water is inferred to have begun near 11 Ma, reflecting climate change (wetter) accompanying the onset of the Gulf Stream, induced by collision of the Panamá Arc against Colombia, interrupting deep-sea Caribbean–Pacific interchange. The Carib Halite concept has important implications for exploration in the oil-rich thrust belts of Colombia, Venezuela and Trinidad. There is also potential for new finds of emeralds and other evaporite-associated minerals.