Height of faceted spurs, a proxy for determining long‐term throw rates on normal faults: Evidence from the North Baikal Rift System, Siberia
Height of faceted spurs, a proxy for determining long‐term throw rates on normal faults: Evidence from the North Baikal Rift System, Siberia
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DOI：
10.1029/2009tc002555
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发表时间：
2009-12
期刊：
影响因子：
4.2
通讯作者：
C. Petit;B. Meyer;Y. Gunnell;M. Jolivet;V. San'kov;V. Strak;N. Gonga-Saholiariliva
中科院分区：
文献类型：
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作者：
C. Petit;B. Meyer;Y. Gunnell;M. Jolivet;V. San'kov;V. Strak;N. Gonga-Saholiariliva
我们提出了在北贝加尔裂谷（NBR），西伯利亚东部的活动正断层的长期抛出率的新结果，基于三角刻面陡坎的统计分析。NBR中的断层边界脊显示出典型的形态，具有由断层垂直集水区分隔的几个连续小平面。在分析的20个断层段的范围内，三角面高度从200米到>900米不等。由于断层崖是在类似的长期气候条件下发展起来的，我们推断，平均小面高度的分散是由于断层落差率的长期差异造成的。我们比较了NBR刻面的形态与先前发表的刻面生长的数值模型中获得的结果。使用刻面高度作为输入，模型结果提供了长期断层抛出率的估计值。丁腈橡胶的抛撒率在0.2和1.2毫米/年之间变化。然后将落差率与累积落差进行比较，累积落差受到盆地地球物理和地层数据的约束。这提供了断层和盆地形成的年龄估计。我们发现，现代阶段的盆地发展开始约3百万年前，除了北贝加尔盆地（1.8Ma）。我们的研究结果还表明，所观察到的投掷的一部分是从早期构造阶段继承。
We present new results on the long‐term throw rates of active normal faults in the North Baikal Rift (NBR), eastern Siberia, based on a statistical analysis of triangular faceted scarps. Fault‐bounded ridges in the NBR display typical morphologies with several contiguous facets separated by fault‐perpendicular catchments. Over a range of 20 fault segments analyzed, triangular facet heights vary from ∼200 to >900 m. As fault scarps have been developing under similar long‐term climatic conditions, we infer that the scatter in mean facet height arises from long‐term differences in fault throw rate. We compare the morphology of NBR facets with results obtained in a previously published numerical model of facet growth. Using facet height as an input, model results provide estimates of the long‐term fault throw rate. NBR throw rates vary between 0.2 and 1.2 mm yr−1. The throw rates are then compared with the cumulated throw, which has been constrained by geophysical and stratigraphic data in the basins. This provides an estimate of the age of fault and basin initiation. We show that the modern stage of basin development started circa 3 Myr ago, except for the North Baikal basin (∼8 Ma). Our results also suggest that a proportion of the observed throw is inherited from an earlier tectonic stage.