| Title: |
Constraints on what controls millennial-scale basin-wide denudation across mountain belts, Asia. |
| Authors: |
Yang, Ye, Binnie, Steven A., Xu, Sheng, Liu, Cong-Qiang, Dunai, Tibor J. |
| Source: |
SCIENCE CHINA Earth Sciences; Jan2025, Vol. 68 Issue 1, p74-93, 20p |
| Subject Terms: |
PHYSICAL geology, EARTH sciences, OROGENIC belts, COSMOGENIC nuclides, MONTE Carlo method, NEOTECTONICS, LANDSLIDES |
| Abstract: |
The terrestrial cosmogenic nuclide dataset consisting of 1233 10Be measurements of fluvial sediment samples across the Asian mountain belts is used to constrain the influence of climate, tectonics and topography on Earth-surface denudation processes. 10Be-derived basin-wide denudation rates were recalculated using a Monte Carlo simulation approach that relied on pixel-by-pixel production rates. The rates derived span four orders of magnitude, from 7.4±0.7 mm kyr-1 (1σ; Central Tibetan Plateau) to 9,646744+777 mm kyr-1 (1σ; Southern Tibetan Plateau), with a median of 186 mm kyr-1. Comparing our results with the traditional basin-wide production rate scaling model using a centroid coordinate and mean elevation, suggests that 96.6% of production rates will be underestimated using the latter method, especially for basins with a large relief. The bias between both methods reaches as large as 40%, caused by basin hypsometry and the nonlinear scaling of production rate with elevation and latitude. Quantification of the correlations between uniformly recalculated denudation rates and tectonics, climate, topography, and rock lithology will facilitate the extrapolation of denudation rates in unknown basins using available data. From the perspective of local scales, precipitation coupled with neotectonics-driven landslides is likely the most influential factor in subtropical Taiwan Island, while topography primarily constrains surface denudation rates in the eastern Tibetan Plateau within a narrow range of precipitation. In highland regions with glacier coverage, such as the Pamir, central and southern Tibetan Plateau, high denudation rates are affected by glaciation, whereas lower precipitation and high erosion base level may limit river incision and evolving relief in the Central Tibetan Plateau. In contrast to local-scale findings highlighting a dominant factor constraining denudation rate, our large-scale quantitative analyses across the Asian mountain belts finds that (1) topographic metrics including slope, relief and normalized channel steepness index show similar, first-order, power-law relationships with denudation rates over millennial timescales, as opposed to the linear relationships suggested to control the surface denudation rate; (2) precipitation, temperature, and vegetation cover relative to elevation and a modern tectonic metric of neotectonic activity based on the kernel density distribution of earthquakes, subordinately constrain the surface denudation, approximating a first-order power-law correlation with denudation rate; and (3) the lithology, as represented by an erodibility index, appears not to correlate with denudation rates at the macro-scale of the Asian mountain belts, possibly due to the complex mixture of different types of rocks and the relative low resolution of erodibility index database. [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |
