Fossils

 

Fossils: A Glimpse into Our Geological History

Over 515 million years ago, ocean waters engulfed what is now present-day Lake Mead for more than 200 million years - kick-starting the extensive paleontological history of the Lake Mead National Recreation Area. It wasn’t until 315 million years ago that those oceans began to subside and the area rotated between hollow seawater and coastline habitats during the course of the next 100 million years. With numerous unique fossils found throughout the 1.5-million-acre park, Lake Mead is home to an exceptional fossil collection discovered by countless researchers in the last 150 years. With these finds, we have a glimpse into our geological past and remarkable species that once lived on earth.

 

Cambrian Period

The Cambrian period – part of the Paleozoic era – could easily be argued the most enormous explosion of evolution known to date. The Cambrian period is regarded as a crucial moment in the emergence of life on earth for a variety of reasons. Before the start of the Cambrian period, most life forms were simple organisms and as they evolved, multicellular life forms evolved and multiplied in the millions of years to follow. Readily fossilized organisms weren’t very common prior to this era, making the Cambrian period significant in our earth’s history. Today, fossils such as Trilobites and Cenozoic Bivalves are found along Cottonwood Wash in Lake Mead, and at the base of Frenchman Mountain on the east side of the Las Vegas valley.

 

Jurassic Period

The Jurassic Period, a 54-million-year time span of the Mesozoic Era, is widely recognized as the age of the dinosaurs. The remnants of aquatic creatures are typically found within Creataceous and Jurassic-age rocks. Frequently found scattered throughout the sedimentary rock formations composing the mountains around Las Vegas are fossils such as crinoids, corals, and brachiopods. As terrestrial landscapes dried up into the Jurassic period 180 million years ago, the present-day Lake Mead area underwent a period of extensive erosion affecting numerous rock layers, resulting in a geological ‘gap’ between the rock record of fossils until the later portion of the Oligocene Era.

 

Oligocene Epoch

The Oligocene epoch, part of the Tertiary Period in the Cenozoic Era, is considered a relatively short span of geologic time compared to other identified periods; however there is an extensive terrestrial record from the fossilized remains of distinct forms of mammals, amphibians, birds and reptiles. Despite the Oligocene epoch lasting fewer centuries, a significant number of transformations occurred during this era such as the development of actual proboscis manifesting as trunks on elephants. An abundance of plant life soon appeared bringing the slow but steady evolution of global grasslands in the time following the Miocene epoch. With the evidence discovered and catalogued over the years, Lake Mead was able to document an impressive list of fossils from this transitional time period.

 

Tule Springs Fossil Beds National Monument

Tule Springs Fossil Beds National Monument (TUSK) is known for one of the most remarkable Pleistocene vertebrae faunas in the southwestern United States: the Tule Springs Local Fauna. The Pleistocene Epoch (commonly referred to as the Ice Age) began almost 2.6 million years ago and lasted until about 11,700 years ago. Thousands of fossils preserved at TUSK include animals such as freshwater snails, dire wolf, sabertooth cat, horses, camel, bison, and the massive Columbian mammoth. TUSK features exposures of the Las Vegas Formation, which provide an invaluable chronologic and climatic context for the dynamic ecosystems of our not-so-distant past between ~570,000 to 8,500 years ago. Today, the National Park Service, TUSK’s partners, volunteers, and researchers work together to continue protecting the land, educating visitors, and preserving the stories of our monumental past.

Learn more about Tule Springs Fossil Beds