of Trinidad. The Los Bajos
wrench fault cuts across the southwest portion of the island. for Trinidad 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 evaporate under the hot tropical sun, leaving behind the heavier asphalt. Bacterial action on the asphalt at low pressures creates petroleum in asphalt. The researchers indicated that
extremophiles inhabited the asphalt lake in populations ranging between 106 and 107 cells/gram. The Pitch Lake is one of several natural
asphalt lakes in the world, including
La Brea Tar Pits (
Los Angeles), the
McKittrick Tar Pits (
McKittrick) and the
Carpinteria Tar Pits (
Carpinteria) in the
U.S. state of
California, and
Lake Guanoco in the
Republic of Venezuela. The regional geology of southern Trinidad consists of a trend of
ridges,
anticlines with
shale diapiric cores, and
sedimentary volcanoes. According to Woodside, "host muds and/or shales become
over pressured and
under compacted in relation to the surrounding sediments...mud or shale diapirs or mud volcanoes result because of the unstable semi-fluid nature of the methane-charged, undercompacted shales/muds." The mud volcanoes are aligned along east-northeast parallel trends. Woodside goes on to say, "The Asphalt Lake at Brighton represents a different kind of sedimentary volcanism in which gas and oil are acting on asphalt mixed with clay. This asphalt lake cuts across
Miocene/
Pliocene formations overlying a complicated
thrust structure." The first wells were drilled into Pitch Lake
oil seeps in 1866.
Kerosene was
distilled from the
pitch in the lake from 1860 to 1865. The Guayaguayare No. 3 well was drilled in 1903, but the first commercial well was drilled at the west end of the lake in 1903. Oil was then discovered in Point Fortin-Perrylands area, and in 1911, the Tabaquite Field was discovered. The Forest Reserve Field was discovered in 1914 and the Penal Field in 1941. The first offshore well was drilled in 1954 at Soldado. ==Microbiology==