Geologists have discovered a link between recent ice mass loss, rapid rock uplift and a gap between tectonic plates that underlie Patagonia.
Scientists at Washington University in St. Louis, led by seismologist Douglas Wiens, the Robert S. Brookings Distinguished Professor in Arts & Sciences, recently completed one of the first seismic studies of the Patagonian Andes. In a new publication in the journal Geophysical Research Letters, they describe and map out local subsurface dynamics.
“Variations in the size of glaciers, as they grow and shrink, combined with the mantle structure that we’ve imaged in this study are driving rapid and spatially variable uplift in this region,” said Hannah Mark, a former Steve Fossett postdoctoral fellow in earth and planetary sciences at Washington University, the first author of the publication. Mark is now a postdoctoral investigator at the Woods Hole Oceanographic Institution.
The seismic data that Mark and Wiens analyzed reveals how a gap in the down-going tectonic plate about 60 miles beneath Patagonia has enabled hotter, less viscous mantle material to flow underneath South America.
Above this gap, the icefields have been shrinking, removing weight that previously caused the continent to flex downward. The scientists found very low seismic velocity within and around the gap, as well as a thinning of the rigid lithosphere overlying the gap.
Read more at: Washington University in St. Louis
Mount Fitz Roy and surrounding peaks as seen during the drive west from the Patagonian desert into the Cordillera, with the details of these monolithic peaks coming into view. (Photo Credit: Ben Tiger)