Continental erosion and large‐scale relief
Continental erosion and large‐scale relief
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DOI：
10.1029/tc007i003p00563
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发表时间：
1988-06
期刊：
影响因子：
4.2
通讯作者：
P. Pinet;M. Souriau
中科院分区：
文献类型：
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作者：
P. Pinet;M. Souriau
世界范围内的大陆侵蚀调查是通过对大型流域的研究，根据水文数据、环境因素和流域地形分布进行的。在每个盆地内部，定义了平均的化学剥蚀率和机械剥蚀率。多元相关分析表明，机械剥蚀率DS与环境因子无关，与流域平均海拔H相关，而化学剥蚀率DD对地形不敏感，但与年均降水量相关。(1)DS(m/10yr)=419×10−6H(M)-0.245，V(解释方差)=95.1%；这一规律适用于与250 Ma以下造山作用有关的盆地。负截距解释为245m/m.y的大陆沉积速率。另一种模型采用临界高程，将侵蚀与沉积分开，同样成功，并导致较低的沉积速率(60-110米/年)。对于这两个模型，一个是由调整的斜率得出的，侵蚀时间常数约为2.5英里/年。(2)DS(m/10yr)=61×10−6H(M)，V=86.5%；零截获表明缺乏大陆存储。由于数据的离散性较大，每个盆地的侵蚀时间常数都是单独计算的；它的范围从15到360英里。讨论了这些结果的构造意义。特别是，短时间常数2.5m.y。与在活动山脉中观察到的约1毫米/年的造山抬升速率相一致。
A worldwide investigation of continental erosion is carried out by the study of large drainage basins, on the basis of hydrological data, environmental factors, and basin relief distribution. Inside each basin, mean geochemical and mechanical denudation rates are defined. A multicorrelation analysis shows that the mechanical denudation rates Ds are uncorrelated with environmental factors and correlated with mean basin elevation H, while chemical denudation rates Dd are insensitive to relief but correlated with mean annual precipitation. Furthermore, two linear relationships between H and Ds are detected: (1) Ds (m/10³ yr) = 419×10−6 H (m) - 0.245, with V (explained variance) = 95.1%; this law concerns basins related to orogenies younger than 250 Ma. The negative intercept is interpreted as a continental sedimentation rate of 245 m/m.y. An alternative model in which one invokes a critical elevation, separating erosion from sedimentation, is equally successful and leads to lower sedimentation rates (60–110 m/m.y.). For both models, one derives from the slope of the adjustments, erosion time constants on the order of 2.5 m.y. (2) Ds (m/10³ yr) = 61×10−6 H (m), with V = 86.5%; this law concerns basins related to older orogenies. The null intercept suggests the lack of continental storage. Because of the more important dispersion of the data, the erosion time constant is calculated separately for each basin; it ranges from 15 to 360 m.y. The tectonic implications of these results are discussed. In particular, the short time constant 2.5 m.y. agrees with orogenic uplift rates on the order of 1 mm/yr, observed in active mountain chains.