QRC members lead and participate in a wide range of disciplinary and interdisciplinary research projects from the study of past earth climates and glaciations to shifts in the geographic distributions and evolution of vegetation and faunal communities, to the evolution and dispersals of the genus Homo and the increasing scales of human modification of earth environments through the Holocene. QRC provides a venue for meeting and collaborating with scholars across Quaternary disciplines. We are also fortunate to be able to provide seed funding and small grants for member research projects. We are especially happy to support grad student and junior scholar research activities, much of which leads to larger, external funding from agencies like the National Science Foundation.
Addressing Rock Artifact Erosion in Mount Diablo State Park, California
Abstract: Artifact bearing sandstone surfaces located in Mount Diablo State Park, California face vandalization and surface degradation from graffiti, foot traffic, grazing, and other anthropogenic influences in addition to broader, longer term effects from Holocene scale microclimatic and environmental changes in the region. Artifacts in the park are currently protected under vandalization clauses, yet a surface stability study may assist in the development of and support toward more effective protection efforts by providing a clearer understanding of the erosive mechanisms altering artifact surfaces. Thus, it is desired from the Mount Diablo community to conduct a quantified, millennial scale study of artifact surface stability. This project attempts to address this desire by selecting four non-artifact sandstone surfaces from two artifact bearing campground sites in the park and analyzing their surface stability histories using a combination of multidisciplinary procedures. Optically stimulated luminescence (OSL) depth profiling will be conducted on extracted rock cores from the sandstone surfaces to produce calculated steady-state centennial to millennial scale surface erosion rates and provide relative surface stability histories of the same scale using luminescence depth curves that document variations in surface luminescence though time. Steady-state erosion rates from sandstone surfaces will also be calculated with 10Be surface data using CRONUS, and then compared with OSL results to identify potential differences with each measurement’s interactions to surface variables (lichens, moss, mineralogy, etc.). Millennial scale probabilistic rock surface spalling analyses also using 10Be data will be incorporated in the analysis to determine possible sequences of surface re-zeroing events that may influence CRONUS and OSL data. Indications of artifact surface erosion influenced by local climatic changes and/or anthropogenic landscape alterations will be analyzed by connecting trends in luminescence attenuation, cosmogenic spalling, and erosion data to distinct historical and prehistorical variations in regional vegetation cover. To make these comparisons, pollen-derived landscape reconstruction algorithms (LRAs) that document regional Holocene vegetative cover through time will be conducted in the Mount Diablo region using pollen sampled from five regionally spaced soil cores within the region. Additional comparisons to historical data and geomorphic observations will also be made to observe direct anthropogenic influences on artifact surface erosion and the landscape. Through comparing millennial scale artifact surface erosion stability data to environmental, climatic and anthropogenic histories in the Mount Diablo region, primary agents and sequences of artifact erosion can be identified from our procedures, providing analytical support for park agendas that aim to mitigate identified erosive factors. The success of this analysis in Mount Diablo can justify the method’s use at other rock artifact bearing sites.