Previously Funded Projects
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.
-
Reconstructing 500 years of relative sea level change in the northern section of Cascadia using a foraminiferal-Bayesian transfer function at Port Alberni, British Columbia, Canada
Abstract: The Cascadia coastline, spanning southern British Columbia to northern California, is prone to some of the greatest megathrust earthquakes (magnitude 8-9) and subsequent tsunamis. Throughout the Holocene, these earthquakes produce patterns of vertical land motion that’s recorded in salt marsh stratigraphy as relative sea-level (RSL) change caused by uplift or subsidence. Given the lack of great earthquakes since 1700 C.E., geological investigation remains the only way to assess reoccurrence intervals and intensities. Proxies including microfossils (i.e., foraminifera) have been used as a reconnaissance tool for obtaining changes in RSL because their assemblages vary strongly to tidal elevation. By using tidally sensitive foraminifera, we can capture an earthquakes full cycle (preseismic and postseismic signals) and quantify coseismic subsidence estimates. Therefore, RSL reconstructions shed light into the magnitude and habit of great Cascadia subduction zone (CSZ) earthquakes. Despite the wealth of successful geologic records documenting coseismic subsidence estimates in Cascadia, most studies have taken place in the U.S., with major knowledge gaps existing in the northern section of the CSZ in British Columbia. The aim of my research is to reconstruct the sea level history over the last ~500 years at Port Alberni, British Columbia. Resolving whether coseismic subsidence occurred at Port Alberni will allow current rupture models to be better constrained. To better understand estimation and variability of past earthquake in the northern section, I will apply a foraminiferal Bayesian transfer function (B-TF) and incorporate prior information to resolve the ongoing debate if Port Alberni subsided during the 1700 C.E. Cascadia earthquake. 48 surface sediment samples were collected at the Port Alberni salt marsh along three transects representing key elevation changes within the marsh spanning from upland to subtidal zones. Surface sediment samples will be used for micropaleontological analysis and loss-on-ignition. Three 1.5 m sediment cores were retrieved from the marsh, will be used to access the microfossil record, and establish a chronology (137Cs, 210Pb and 14C). A B-TF will be used to relate the surface foraminifera assemblages and their elevations, to their fossil assemblage, creating the first high-resolution sea level history reconstruction at Port Alberni.
It is anticipated that the results will determine better understanding of plate boundary processes whether Cascadia produces full trench or multi-segment ruptures. We can additionally prepare coastal communities into resilient ones’, by equipping them with risk assessment plans, evacuation strategies, and inundation and coastal erosion maps.
Report: pending