Name: Rancho La Brea.
Location: Los Angeles, California.
Age: 38,000 years old to recent.

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The taphonomy of Rancho La Brea

Figure 1. The beginning of another miring event in the La Brea tar pits. Once a herbivore is trapped, carnivores begin to become attracted and are themselves mired. (Modified after Turner and Anton, 1997.)

Figure 2. Once the animals have died and their soft-tissues have been removed by decay/scavengers their bones begin to accumulate. (Modified after Turner and Anton, 1997.)

Taphonmy of the tar pits:

A miring event begins with the entrapment of an animal of any type. Once this animal is dying/dead it begins to attract carnivores and scavengers. They themselves become mired in the tar and become part of the accumulation.

This sequence of events can explain many oddities of the assemblage, such as the apparent rarity of nocturnal animals. It is believed that at night the tar would have hardened slightly as the air cooled, and fewer animals would have become mored. In addition, this would explain the presence of some aquatic organisms in small pools of water on the surface of the tar.

The anoxic environment of the seeps has preserved the bones exceedingly well. However, no soft-body preservation is yet known.

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