La Brea Tar Pits Los Angeles California

The Historical La Brea Tar Pits

Located in urban Los Angeles, the La Brea Tar Pits are a collection of tar pits around which Hancock Park was built. It has been a tens of thousands of years since natural asphalt (also known as asphaltum or bitumen, pitch or tar; in Spanish, brea) has crept up from the earth in this area. Dust, leaves, and water are frequently used to hide the tar. The bones of caught animals were kept in tar for many decades.


Oil seeps from the ground into tar pits, which are made up of heavy oil fractions known as gilsonite. Crude oil flows up through the 6th Street Fault into Hancock Park from the Salt Lake Oil Field, which underlies part of the Fairfax District to the north of the park.


After reaching the surface and forming pools of oil, the lighter parts of the petroleum biodegrade or evaporate, causing the asphalt to harden and solidify. Normally, the asphalt hardens into stubby mounds as a result of the process. Multiple locations throughout the park have pools and mounds.


A total of 100 sites were excavated between 1913 and 1915 in search of large mammal bones, and the tar pits that can be seen today were all created by humans: the lake pit was originally an asphalt mine, and the other visible pits were created as a result of explorers excavating more than 100 sites between 1913 and 1915 in search of large mammal bones. Because of an accumulation of asphaltum, dust, leaves, and water, these excavations have progressively been filled in over time; yet the tar pits that were created by them still remain.


Since the beginning of recorded history, this seepage has occurred on a regular basis, resulting in the formation of a layer of asphalt thick enough to imprison animals. Eventually, water, dust, and leaves would accumulate on the deposit.


It was common for animals to wander into the building and become trapped, eventually dying. Animals would be confined, and predators would be drawn in to eat them. Predators would get trapped as well. Asphalt seeps through the bones of a dead animal as they sink, turning them a dark brown or black color as the asphalt absorbs the moisture.


Lighter fractions of petroleum evaporate from the asphalt, leaving behind a more solid substance that encases the bones and acts as a protective barrier. Extraction of huge animal fossils has revealed that asphalt also contains microfossils such as wood and plant fragments, rodent bones, insects, mollusks, dust, seeds, leaves, and even pollen grains, which have been discovered in the asphalt.


This article was originally posted at Once Over Restoration.