December 2, 2013
GECSC Geologist Sarah Shafer co-authored chapters 3, 4, and 5 in the report Climate Change in the Northwest: Implications for Our Landscapes, Waters, and Communities published by Island Press. The report is a regional technical input contribution to the U.S. National Climate Assessment and has been covered by popular media. The report reviews the current understanding of potential future climate changes and their effects in Oregon, Washington, and Idaho.
December 2, 2013
Comparing approaches to spatially explicit ecosystem service modeling: A case study from the San Pedro River, Arizona
By Ken Bagstad (GECSC), Darius Semmens (GECSC), and Robert Winthrop. Published in Ecosystem Services.
This study compares results obtained from two leading open-source ecosystem services modeling tools, ARIES and InVEST, when applied to a project in the San Pedro River watershed on the U.S.-Mexico border. Locally important services that both modeling systems could address—carbon, water, and scenic viewsheds—were modeled. It was found that results were more closely aligned for landscape-scale urban-growth scenarios and more divergent for a site-scale mesquite-management scenario.
November 27, 2013
Chronology and provenance of last-glacial (Peoria) loess in western Iowa and paleoclimatic implications
By Dan Muhs (GECSC), Arthur Bettis III, Helen Roberts, Stephen Harlan, Jim Paces (GECSC), and Rich Reynolds (GECSC). Published in Quaternary Research.
Modeling suggests that the increased dustiness Earth experienced during the last glacial period was due to generally stronger, more frequent winds. This study tested that model by creating a chronology of the loess deposits found in Loveland, Iowa—one of the thickest such deposits from last-glacial-age found in the world. The findings confirmed that increased dustiness during the last glacial period was driven largely by enhanced gustiness, forced by a steepened meridional temperature gradient.
November 25, 2013
Evaluation of Pleistocene groundwater flow through fractured tuffs using a U-series disequilibrium approach, Pahute Mesa, Nevada, USA
By Jim Paces (GECSC), Paul Nichols, Leonid Neymark, and Harihar Rajaram. Published in Chemical Geology.
Groundwater flow through fractured felsic tuffs and lavas at the Nevada National Security Site represents the most likely mechanism for transport of radionuclides away from underground nuclear tests at Pahute Mesa. The methods employed for this study found that many Pahute Mesa fractures represent stable hydrologic pathways over million-year timescales. Furthermore, these methods can potentially identify areas within the saturated zone that represent zones of greater or lesser groundwater flow, the nature of geochemical processes affecting U mobility and transport, and the likelihood of whether or not rock matrix contributes to retardation or dispersion of constituents of contaminant plumes.