Dating cole in brea
The tar is often covered with dust, leaves, or water.
Over many centuries, the tar preserved the bones of trapped animals. Page Museum is dedicated to researching the tar pits and displaying specimens from the animals that died there.
They were believed to be from the last glacial period, believed to be about 30,000 years ago.
After radiocarbon dating redated the last glacial period as still occurring 11 to 12,000 years ago, the fossils were redated to be 10–20,000 years old.
The original Rancho La Brea land grant stipulated that the tar pits be open to the public for the use of the local Pueblo. Orcutt is credited, in 1901, with first recognizing that fossilized prehistoric animal bones were preserved in pools of asphalt on the Hancock Ranch.
Asphalt and methane appear under surrounding buildings and require special operations for removal to prevent the weakening of building foundations.
The pits still ensnare organisms today, so most of the pits are fenced to protect humans and animals.
The Native American Chumash and Tongva people living in the area built boats unlike any others in North America prior to contact by settlers.
In 2007, researchers from UC Riverside discovered that the bubbles were caused by hardy forms of bacteria embedded in the natural asphalt.
After consuming petroleum, the bacteria release methane.
The Portolá expedition, a group of Spanish explorers led by Gaspar de Portolá, made the first written record of the tar pits in 1769.