The Caribbean island of Trinidad is home to the world’s largest deposit of natural asphalt, called Pitch Lake.
The surface of the lake is a mostly solid carpet of asphalt that can be walked on, attracting some 200,000 tourists each year.
The lake is also mined for asphalt — called “pitch” in its crude, unrefined form — sold around the globe for the use in the paving highways, race tracks, bridge decks, and airport runways.
This is Pitch Lake. It may look like a giant parking lot, but make no mistake, it is the only commercial viable source of natural asphalt in the world.
The formation of natural asphalt lakes is not fully understood (Los Angeles' La Brea Tar Pits and Venezuela's Lake Guanoco are other examples of natural asphalt-like deposits). Scientists think Pitch Lake was created when the Caribbean continental plate forced its way below the edge of another plate. This pushed up oil deposits from deep within the earth to the surface.
When the oil rises to the surface, the lighter liquid ingredients slowly evaporate, leaving only the harder asphalt. This harder asphalt is mostly a mixture of water, gas, oil, and sand.
Most of the surface is safe to walk on, and the asphalt is soft and forgiving under a pair of shoes. In the rainy season, people often wade in sulfur-rich pools that form, which are believed to be healing.
Visitors are warned that the hot, softer tar in some parts acts like quicksand and can swallow wandering livestock or wayward tourists.
The lake has also been known to spit things out. The local visitor centre boasts a few ancient local pottery shards, and some fossilized remains of a mastodon and a giant prehistoric sloth.
The lake isn't just a tourist destination — it's also the centre of a booming industry. Crude asphalt is surface-mined and and then placed into large, metal bins. The bins are moved to a refinery close to the lake.
Pitch lake is not inexhaustible. The last estimate from 10 years ago, indicated that it would last another 400 years at its current rate of extraction.
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