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Find Your Science at GSA
2 Aug 2011
GSA Release No. 11-45
Christa Stratton
Director of Education, Communication, & Outreach

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August 2011 GSA Today cover


Understanding Earth's eroding surface with 10Be
Eric W. Portenga, Dept. of Geology, University of Vermont, 180 Colchester Ave., Burlington, Vermont 05405, USA,; and Paul R. Bierman, Dept. of Geology and Rubenstein School of the Environment and Natural Resources, University of Vermont, 180 Colchester Ave., Burlington, Vermont 05405, USA,; doi: 10.1130/G111A.1, pages 410,

Boulder, CO, USA –The modification of Earth's surface by erosion is one of the most important geological processes in terms of its impact on society, as well as its influence on the geological record, but geologists have been lacking a well-determined compilation of pre-human rates of erosion. In a groundbreaking compilation of 1528 calculations of surface erosion rates from 80 study areas from all over the world, authors Eric Portenga and Paul Bierman of the University of Vermont provide a valuable look at how rates of erosion vary in differing climates and tectonic settings in the recent geological past.

The erosion rates in their compilation are determined by measuring the abundance of radioactive isotopes produced in rocks exposed to cosmic radiation at Earth's surface. Their compilation has found that bare rock outcrops had significantly lower rates of erosion than surfaces covered with even thin layers of soil, pointing out the global importance of soil formation as a geomorphic process. They also found several factors that are most important to erosion rates; not surprisingly, the highest rates of erosion in the recent geologic past occur in drainage basins and in areas with the steepest slopes. The analysis of their compilation has revealed that variations in global and regional erosion rates are best explained by an interaction of several processes including surface slope and elevation, tectonic activity, and climatic setting. One of the more interesting applications of this global analysis of erosion rates will be to better understand how changes in present climate and land use will likely influence long-term rates of erosion.

Peer-reviewed GSA TODAY articles are open access. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GSA TODAY in articles published. Contact Christa Stratton for additional information or assistance.


GSA TODAY is The Geological Society of America's science and news magazine for members and other earth scientists. Refereed lead science articles present exciting new research or synthesize important issues in a format understandable to all in the earth science community. GSA Today also often features a refereed "Groundwork" article — tightly focused papers on issues of import to earth science policy, planning, funding, or education. All GSA Today articles are open access at