Microbial oxidation of lithospheric organic carbon in rapidly eroding tropical mountain soils.

Lithospheric organic carbon ("petrogenic"; OC) is oxidized during exhumation and subsequent erosion of mountain ranges. This process is a considerable source of carbon dioxide (CO) to the atmosphere over geologic time scales, but the mechanisms that govern oxidation rates in mountain landscapes are poorly constrained. We demonstrate that, on average, 67 ± 11% of the OC initially present in bedrock exhumed from the tropical, rapidly eroding Central Range of Taiwan is oxidized in soils, leading to CO emissions of 6.

Links between erosion, runoff variability and seismicity in the Taiwan orogen.

The erosion of mountain belts controls their topographic and structural evolution and is the main source of sediment delivered to the oceans. Mountain erosion rates have been estimated from current relief and precipitation, but a more complete evaluation of the controls on erosion rates requires detailed measurements across a range of timescales. Here we report erosion rates in the Taiwan mountains estimated from modern river sediment loads, Holocene river incision and thermochronometry on a million-year scale.