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.
Investigating fault scarp degradation in jointed basalt in southern Iceland
Abstract: Fault scarps in jointed bedrock hold information key to illuminating a region’s recent tectonic history, such as timing of faulting and magnitude of events, if their morphological evolution through time can be deciphered. This project will investigate how jointed bedrock fault scarps record fault activity and determine the principal drivers of bedrock scarp degradation. This study will focus on characterizing this evolution in basalt-hosted normal fault scarps in southern Iceland, where scarps are abundant and well-exposed. The ongoing oceanic rifting in southern Iceland is marked by late Quaternary-to-recent tectono-volcanic systems identified as the East and West Volcanic Zones (EVZ and WVZ) and is characterized by numerous zones of fissures and faults that affect recent basaltic lava flows. In multiple sites, a single fault cuts through flows of various ages. Close correlation exists between the vertical throw of the major faults and the age of the affected lavas in outcrops, with scarps in Pleistocene flows exhibiting throws of several tens of meters or more and those in Holocene flows less than ten meters. Assuming continuous faulting in this region through the Holocene, we can use the age of the basalt flow as an approximation of the time of scarp formation. The morphology of a scarp from the same fault in each differently aged flow will thus offer a snapshot of its evolution through time, providing the opportunity to establish a space-for-time substitution investigating the tempo and style of scarp growth and degradation along a fault. This study will focus on characterizing the morphology of these bedrock scarps of different ages. We will quantify the degree to which these scarps have retreated through time by measuring the setback between the trace of the scarp in the youngest lava flows and those that preceded it. We will also determine the principal mechanisms of retreat and their timing. The processes that control the retreat of bedrock scarps have been explored in the specific contexts of waterfalls and glacial headwalls, but are still poorly constrained for fault scarps. We hypothesize that scarp degradation is dominated by strong ground motion, with scarps in the more seismically active areas experiencing higher rates of retreat. Cosmogenic exposure dating on a selected scarp will provide the overall retreat rate of the scarp and shed light on the processes that govern its degradation.