In-situ cosmogenic 36C1 denudation rates of carbonates in Guizhou karst area

This study quantifies surface denudation of carbonate rocks by the first application of in-situ cosmogenic 36C1 in China. Concentrations of natural C1 and in-situ cosmogenic 36C1 in bare carbonates from Guizhou karst areas were measured with isotope dilution by accelerator mass spectrometer. The C1 concentration varied from 16 to 206 ppm. The 36C1 concentrations were in range of （0.8-2.4）x106 atom g-l, resulting in total denudation rates of 20-50 mm ka-1 that averaged over a 104-105 a timescale. The 36Cl-denudation rates showed roughly a negative correlation with the local mean temperature. This preliminary observation may suggest the variations of proportions of chemical weathering and physical erosion in denudation process, depending upon local climatic conditions.