The asphalt seeps of Rancho La Brea, aka the La Brea Tar Pits, constitute one of the world’s richest fossil sites. Although the asphalt had been used for a variety of different purposes since prehistoric times, it wasn’t until the late nineteenth century that the seeps were recognized as a prolific source of fossils. The asphalt acts as a superb preservative that enables anatomical studies, radiometric dating, and isotopic analysis of the fossils and these provide a panoramic view of life in southern California during the waning phases of the Pleistocene Ice Age. The number and diversity of recovered fossils led to the site’s recognition as the type locality of the Rancholabrean North American Land Mammal Age and public interest led to its selection as a state historic site and one of the first National Natural Landmarks.
During the first part of the twentieth century the scientific focus was on documenting the iconic late Pleistocene megafauna. The proportions of the recovered skeletal elements of these animals suggested that the asphalt seeps formed a carnivore trap. Subsequent emphasis on smaller elements of the biota doubled the number of recognized species and helped document the local habitats. More recent studies have placed emphasis on evolutionary and environmental changes during the 50,000 year sequence. After more than a century of study, the Rancho La Brea biota is still a fertile source of new information about the late Pleistocene biota.
8-28-2015 Updates for programs and CGS Officers 2015-2016, Add New CGS-PSAAPG Convention Page