Series: Park Paleontology News - Fall 2017
Viva DEVA: A Valley of Death, Full of Life
Article by Matthew Ferlicchi, Paleontology Intern, Death Valley National Park
for Park Paleontology Newsletter, Fall 2017
Multicellular life begins to show up in the fossil record around 600 million years ago. The story of life from that time period has yet to be fully told, one reason being the earliest forms of life may not have had the resiliency to fossilize at all. I mention this because Precambrian fossils from around that time have been documented in Death Valley National Park, DEVA for short. The time represented by the rocks of DEVA spans over a billion years. Within them, fossils abound from various time periods, which means many different life forms are represented within the park boundaries. Some of the most famous of these are the 4 million year old Pliocene fossil tracks of Copper Canyon. Perhaps less well known are the 400 million year old Heterostracan fossils, a type of jawless fish from the Devonian. They may soon gain in popularity as they were chosen for the 2017 National Fossil Day logo. From 600 to 400 mya, all the way up to a "recent" 4 million years ago, one starts to get an appreciation of the deep history of DEVA and the story it can tell. It's a story of the history of our planet, and of life itself.
After receiving my Masters in Geoscience from Montclair State University in Montclair, New Jersey, I wanted an opportunity to work in paleontology. I knew I had a passion for fossils and understanding past life, but never really nailed down a specific time period or taxa to focus on. Luckily for me, Death Valley would never force me to choose. It would instead provide fossiliferous formations from the Precambrian to the recent, and my position would make them all accessible, provided I put in the work.
Death Valley is vast, equipped with harsh environments, long distances and of course heat. It can regularly reach 120° F in the summer and will usually exceed that. At that time, the only thing one should be discovering is air conditioning. During my internship as park paleontologist it was my job to document old sites for the park, and, if possible, discover new ones. While attempting to hunt them down in a park the size of the state of Connecticut proved difficult, there have been some discoveries on my watch.
One of my first weeks at DEVA, I went hunting into the red banded outcrops known as Kit Fox Hills, if only to get an up close look at the geology. What I stumbled upon was a wonderfully speckled rock that certainly seemed to be more than just that. It was a partial fossil palm stem with excellent preservation, preserving the network of fiber vascular bundles that carry nutrients and water through the plant. It had eroded out of the lacustrine sediment above, and just below a dated ash tuff layer dated just under 3.5 ma. The early indications are that this specimen belongs to the genus Washingtonia, a potential ancestor of the modern California fan palm. Success! If I accomplish nothing else, I've added to the parks fossil collection in an area not known to be fossiliferous. Instead of taking the next few months off, I decided to keep looking.
Though Death Valley's geology spans over a billion years of geologic time, Mesozoic sediments are not well represented in the park, and fossils of that time were said to not exist. With the help of the USGS map, I would seek out the only sliver of sedimentary rock from the era and find out for myself. This led me to the Butte Valley formation in the southwest area of the park. As I hiked across an alluvial plain and over a ridge, I questioned whether I was making good use of my time at the park. Fortunately, I was walking straight towards an outcrop teeming with ammonite impressions. This find has gotten the attention of paleontologists in Alaska and Budapest. As it turns out, they've been discovered before, but perhaps misidentified as early Triassic and may in fact be an early Jurassic assemblage, a difference of about 50 million years. Their biostratigraphic significance may have implications for our understanding of the tectonics of the region during the Mesozoic.
Perhaps it's our affinity with vertebrates that makes finding their fossilized bones so exciting to discover. I had hoped to come across some during my time in DEVA. With the suggestion of a long time park volunteer, I spent a Saturday afternoon hiking through the beautifully striated outcrops known as Lake Rogers. Vertebrate fossils are known from this formation, though most are highly fragmented and scattered. My timing could've been better, as winds began to pick up, providing me the experience of walking through a sandstorm. The late Pleistocene Lake Rogers sediments consist of what were thought to be ancient lake sediments that have been cut through by erosion, leaving many canals to walk through with the stratigraphy visible. As I came upon one of these outcrops, I noticed large clasts indicative of a high energy event. Among them, a cross-section of a mammoth tusk! It's still unclear how much of the Mammuthus tusk remains, as it has not yet been excavated. Subsequent trips back to Rogers have produced a Mammuthus mandible, Equus limb bones and a potential Camelid bone. Perhaps most importantly, it's caught the attention of the USGS's Kathleen Springer and others, who's work on Tule Springs fossil beds has provided a detailed account of the paleoclimate in the region. Her assessment of Lake Rogers is that it wasn't a lake at all, but an ancient marsh that has dried up and reemerged through time. These beds may be correlative to the beds of Tule Springs, thus providing a regional look at the changing paleoclimate.
My short time at DEVA has been a rewarding and unique experience. Six months is of course short when one realizes that even years spent in the park would not culminate in a full understanding of the deep history the park beholds. I've spent long hours driving on pavement and dirt roads, hiking and camping for days and nights with unsuccessful attempts at localities. I've also felt the thrill of discovery, the satisfying exhilaration for all the hard work put in. I plan to return to DEVA this fall, to continue projects that have been started, and hopefully create some new ones. Those Precambrian fossils that have been documented in the park are most certainly on the list. If they're out there, they just need to be found.