Pitch Lake, La Brea, Trinidad

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.
Microbial life exists in the lake. The researchers indicated that extremophiles inhabited the asphalt lake in populations ranging between 106 to 107 cells/gram.