PITCH LAKE, TRINIDAD AND TOBAGO
Though it looks a lot like treacle, this lake is the largest natural deposit of asphalt in the world. Other natural pitch lakes include the La Brea Tar Pits (Los Angeles), McKittrick Tar Pits (McKittrick) and Carpinteria Tar Pits (Carpinteria) in the US state of California, and Lake Guanoco in the Republic of Venezuela. The lake is found at La Brea in southwest Trinidad and covers around 40 hectares and is 75 metres deep. Debris such as boulders, fallen trees and refuse can get caught in the sticky surface; the pitch hardens around the object and effectively turns it to stone.
The lake was discovered by Sir Walter Raleigh in 1595; asphalt exported from Pitch Lake was used to pave the streets of some regions of New York. It is currently mined for asphalt.
The lake is believed to be at the intersection of two faults which allowed oil from a deeper deposit to be forced up. The faults formed in connection with subduction under the Caribbean Plate. The lighter elements in the oil evaporated and left the heavier asphalt. The bacterial action on the asphalt at low pressures creates the petroleum in asphalt.
Extremophiles inhabit the lake in populations between 106 and 107 cells/gram. Single celled organisms like archaea and bacteria co-exist, thriving in the oxygen-free environment, eating hydrocarbons and respiring with metals. Novel fungal life forms have also been found, they use the available asphaltenes as a sole carbon and energy source.
It has been suggested by various scientists that Pitch Lake is the closest thing on Earth to the kind of hydrocarbon lakes found on Saturn’s moon Titan.
Photo essay: http://www.richard-seaman.com/Travel/TrinidadAndTobago/Trinidad/PitchLake/
Photo credit: http://www.richard-seaman.com/Wallpaper/Travel/Caribbean/PitchLake.jpg