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

Abstract

This study quantifies surface denudation of carbonate rocks by the first application of in-situ cosmogenic 36 Cl in China. Concentrations of natural Cl and in-situ cosmogenic 36 Cl in bare carbonates from Guizhou karst areas were measured with isotope dilution by accelerator mass spectrometer. The Cl concentration varied from 16 to 206 ppm. The 36 Cl concentrations were in range of (0.8-2.4)10 6 atom g −1 , resulting in total denudation rates of 20-50 mm ka −1 that averaged over a 10 4 -10 5 a timescale. The 36 Cl-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. in-situ cosmogenic 36 Cl, denudation rate, climatic condition, carbonate, Guizhou Citation:Xu S, Liu C Q, Freeman S, et al. In-situ cosmogenic 36 Cl denudation rates of carbonates in Guizhou karst area.

Limited influence of climatic gradients on the denudation of a Mediterranean carbonate landscape

“…Matsushi et al (2010) showed the importance of chemical dissolution in karst areas under subtropical climates in Japan and the greater impact of physical erosion in subarctic environments. Xu et al (2013) came to similar conclusions studying samples collected in various climatic contexts in China and whose sampling altitudes ranged from 500 to 2300 meters above sea level. They determined denudation rates varying from 17 to 47 mm/ka that are roughly inversely proportional to the Mean Annual Temperature (MAT) at the sampling sites.…”

Morphological controls on the dynamics of carbonate landscapes under a mediterranean climate

“…Xu et al. () found similar denudation rates in the Guizhou karst, China (MAP 900–1,300 mm). Both studies obtained denudation rates with similar ranges to that of our dataset in the Luberon where MAP is 700 mm, which highlights the importance of water availability and chemical dissolution in controlling carbonate weathering, as proposed by Ryb, Matmon, Erel, Haviv, Benedetti et al.…”

“…Most of these studies have focused on areas dominated by quartz‐rich bedrock, due to the routine use of in‐situ 10 Be to determine denudation rates. In contrast, only a few studies have used 36 Cl to investigate the denudation in carbonate‐dominated landscapes (Matsushi et al., ; Stone, Allan, Fifield, Evans, & Chivas, ; Xu et al., ). Recent work by Ryb, Matmon, Erel, Haviv, Benedetti et al.…”

Chemical Versus Mechanical Denudation in Meta‐Clastic and Carbonate Bedrock Catchments on Crete, Greece, and Mechanisms for Steep and High Carbonate Topography

“…Stone et al () first established the use of the 36 Cl cosmogenic nuclide to determine bedrock denudation rates in limestones. Previous studies of 36 Cl denudation rates have focused on exposed bedrock denudation rates, where dissolution is the dominant lowering process (Godard et al, ; Schaller et al, ; Thomas et al, ; Xu et al, ). However, quantification of carbonate denudation at the catchment scale is needed to integrate the effects of mechanical denudation processes along hillslopes and channels and to understand its impact on relief generation.…”

“…Note that carbonate lithologies are disproportionately over-represented at high elevations. Xu et al, 2013). However, quantification of carbonate denudation at the catchment scale is needed to integrate the effects of mechanical denudation processes along hillslopes and channels and to understand its impact on relief generation.…”