California Desert Studies Consortium

Transdisciplinary Studies Provide Keys to Connecting Climate, Ancient Desert Lakes and People of the Past

 


On the shores of ancient Lake Mojave (today’s Soda and Silver Lake playas), Dr. Edward Knell, professor of anthropology at California State University, Fullerton, and Dr. Matthew Kirby, professor of geological sciences at California State University, Fullerton, have undertaken a transdisciplinary, long-term research program to better understand the linkages between past human lifeways and changes in past climate. The Desert Studies Center (DSC) has served as a base for this research since 2009. Transdisciplinary research collaborations focused on Lake Mojave began in earnest in the 1930s and continue today. Much like previous researchers who sought to date the shorelines and place the many archaeological sites in chronological context, Dr. Knell and Dr. Kirby have combined the efforts of archaeologists, geologists and students to address similar and more nuanced research goals, but now with the advantage of newer methods and technologies.

Kirby and his geology students focus on paleolimnology, or the study of past climates from lake sediments, to improve our understanding of Lake Mojave’s shorelines, including the chronology, extent of wetland habitat and changes in past climate. These interests dovetail nicely with Knell’s research on determining how past peoples adjusted their lifeways to meet changes in climate—changes that affected the availability of food resources, how people moved across the landscape and where people settled or conducted their activities along the lake margins. Together, one of the biggest questions the Knell/Kirby collaboration is addressing is how chronological changes in lake level influenced the extent and placement of wetlands and the potential plant and animal foods available for humans. Understanding these responses will help determine how such changes affected the way Paleoindians (possibly as early as the end of the last ice age) and later groups moved to and around pluvial Lake Mojave and the playa lakes that followed (i.e., Silver and Soda Lake playas).

Some of the latest geological findings are the product of climate reconstruction from a recently acquired lake sediment core. Kirby and colleagues (including undergraduate and graduate co-authors) reconstructed 14,800 years of lake history, inferring a more complex late glacial-through-Holocene lake history than previously known. Moreover, their results suggest a strong 14,800-year coupling between Pacific Ocean-atmosphere processes and winter precipitation over the Silver Lake drainage basin. Comparisons to other regional paleoclimatic archives reveal a consistent spatial pattern of Holocene climate change in the southwestern United States, including Southern California. Perhaps most striking is evidence for a sustained, millennial-scale period of aridity in the mid-Holocene.

Knell’s research began in 2009 with field seasons each summer through 2017 that resulted in the systematic pedestrian (walking) survey and in-field analysis of nearly 5,000 stone artifacts from 6.5 square miles of shoreline along Soda and Silver Lake playas. At two bedrock quarries, his team determined how stones from fine-grained volcanic outcrops were reduced at the quarry sites and then transported to shoreline sites for further modifications. Furthermore, by making geochemical links between the stone artifacts and specific quarry sources, he determined that people arrived at Lake Mojave primarily from the northwest, where obsidian from the Coso volcanic field (about 175 km to the northwest) and Goldstone dacite (about 70 km to 80 km to the northwest) are found. Others came from directly north, from the Shoshone Mountain obsidian source (about 140 km).

Knell and Kirby’s teams consistently include graduate and undergraduate students from Cal State Fullerton and other CSU and state university schools. Participants have used their experiences to produce anthropology master’s theses as well as geology master’s and bachelor’s theses. While statione​d at the Desert Studies Center for fieldwork, students not only gain important hands-on experience in their field of science, they also understand how their science links to the many past and present natural and cultural phenomena around the center. This transdisciplinary archaeology and geology research helps students make these important connections, which has made the DSC an invaluable aspect of their joint research program.

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