Pitch Lake, La Brea, Trinidad

Since its re-discovery, there have been numerous research investigations into the use and chemical composition of this material. Above all, there have been countless theories, postulations, and conclusions as to the size, source, and origin of the asphalt.
Geology
The origin of Pitch Lake is related to deep faults in connection with subduction under the Caribbean Plate related to Barbados Arc. The lake has not been studied extensively, but it is believed that the lake is at the intersection of two faults, which allows oil from a deep deposit to be forced up. The lighter elements in the oil evaporated, leaving behind the heavier asphalt. Bacterial action on the asphalt at low pressures creates petroleum in asphalt.