Geochemistry, Geophysics, Geosystems

Cover image for Vol. 18 Issue 10

Impact Factor: 3.201

ISI Journal Citation Reports © Ranking: 2016: 20/84 (Geochemistry & Geophysics)

Online ISSN: 1525-2027

Increased erosion rates due to uplift and glacial erosion

Around the world, geologists have found overwhelming evidence that starting about 5 million years ago, erosion rates began to increase. Geoscientists, puzzled about the cause of this increase, are specifically debating whether it is due to climate change or an increase in rock uplift as the Earth’s topography evolved.

In the Swiss Alps, the Bergell intrusion—a massive igneous sequence that is exposed in several locations—has the lithology and high relief needed to test hypotheses of why erosion rates dramatically changed. Recently, Fox et al. developed a new model linking radiometric ages, recording the cooling of mineral grains as they approached Earth's surface, across the Bergell to the topographic evolution of the region. The authors identified a period of slow uplift that corresponded to slow erosion rates from 20 to 5 million years ago, then an increase in erosion rates up to 0.7 kilometer per million years.

The authors propose that this change is due to increased glacial erosion and rock uplift that started 4 million years ago, rather than a changing climate.

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