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. Since the program’s launch in 2014, we have funded over 100 research projects.
Examining the Chronology of the Foothills Erratics Train, Alberta, with in-situ Optical Surface Exposure Dating
Abstract: Optically stimulated luminescence (OSL) depth profiles from quartz can be used to extrapolate rock surface exposure ages with an understanding of a sample’s light attenuation and OSL bleaching behaviors. However, the current measuring procedure for producing depth profiles, which involves measuring the luminescence of millimeter slices from surface core samples, offers low resolution data, limiting age and parameter extrapolative accuracy for the dating technique. Further, OSL anomalies from non-quartz mineralogical variations in the measured samples can cause depth profile data scatter in dating quartz rich rocks, further limiting age extrapolative accuracy.
Obtaining OSL depth profiles with the use of sub-millimeter OSL laser scanning measuring protocols on transverse core slices, rather than obtaining OSL from millimeter slice segments, has potential for improving the data resolution of OSL depth profiles. Further, with this spatially resolved OSL data, one can identify and eliminate OSL non-referential to light exposed quartz with the use of scanning electron microscopy energy dispersive x-ray spectroscopy (SEM-EDS) measures. This filtering process may reduce the amount of data scatter present in depth profile datasets of heterogeneous rock mediums, which may offer improvements in parameter extrapolative accuracy for quartz OSL dating.
Thus, the QRC sponsored project aims to trial using these enhanced luminescence measuring protocols to surface date three erratics from the Foothills Erratics Train in Alberta, Canada. The erratics are believed to have been deposited along the margins of the Cordilleran and Laurentide Ice Sheets during their latest glacial retreat. Ongoing controversies concerning the surface exposure dates of these erratics using cosmogenic nuclides have complicated interpretations of glacial histories and interactions between the Cordilleran and Laurentide ice sheets during the upper Pleistocene, with particular questions of when an ice-free corridor between the Laurentide and Cordilleran ice sheets opened up, which would have allowed for the migration of humans into North America. Optically stimulated luminescence is a chronometer more sensitive to millennial timescales than what cosmogenic nuclide dating can provide, and may be able to document retreat direction chronologies via surface exposure dating applications using the proposed novel OSL measuring techniques.