1. Height of faceted spurs, a proxy for determining long-term throw rates on normal faults: Evidence from the North Baikal Rift System, Siberia
- Author
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Vladimir San'kov, Bertrand Meyer, Carole Petit, Nahossio Gonga-Saholiariliva, Marc Jolivet, Yanni Gunnell, and Vincent Strak
- Subjects
Rift ,010504 meteorology & atmospheric sciences ,Structural basin ,010502 geochemistry & geophysics ,Fault scarp ,01 natural sciences ,Proxy (climate) ,Paleontology ,Tectonics ,Geophysics ,13. Climate action ,Geochemistry and Petrology ,Statistical analysis ,Triangular facet ,Geology ,0105 earth and related environmental sciences - Abstract
[1] 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.
- Published
- 2009
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