FOSSIL VERTEBRATE TRACKS OF DEATH VALLEY NATIONAL PARK: INDICATION OF A LARGE MAMMAL AND BIRD POPULATION IN DEATH VALLEY DURING THE MIOCENE AND PLIOCENE

Extremely well preserved fossil tracks and trackways of birds, camels, horses, cats, proboscidians and other vertebrate ichnotaxa are preserved in Miocene and Pliocene lacustrine deposits of Death Valley National Park. Four localities within Death Valley are known however only one locality within the Copper Canyon Formation is well documented. The other three localities are within unnamed and unmapped deposits. The Copper Canyon Formation represents approximately 1800 m of conglomerates, basalt flows, and fluvial-lacustrine sediments exposed within Copper and Coffin Canyons on the west side of the Black Mountains in southern Death Valley National Park, California. Twenty-six ichnospecies of cat, camel, horse, mastodon, and bird tracks have been identified from 60+ localities spanning over 1200 meters of lacustrine deposits. These deposits have been dated between 5-3Ma. The other localities within Death Valley contain similar tracks as those found within the Copper Canyon Formation and therefore are assumed to be of similar age. Tracks are preserved with mudstone beds interpreted as play-mudflats that also preserve numerous shoreline features including mud cracks, ripples, and raindrop impressions. In comparison fossil vertebrate bones are rare within the Cenozoic deposits of Death Valley. The abundance and diversity of mammal and bird tracks within Death Valley suggest a large animal population existed in Death Valley at this time. On-going research looking at mammal and bird track diversity will enable a better understanding of the animal population in Death Valley at this time.