Probing the edge of the West African Craton: A first seismic glimpse from Niger

Autor: James Wookey, Jeanette F. Di Leo, Neil D. Selby, J. Michael Kendall
Rok vydání: 2015
Předmět:
Zdroj: Di Leo, J F, Wookey, J, Kendall, J M & Selby, N D 2015, ' Probing the edge of the West African Craton : a first seismic glimpse from Niger ', Geophysical Research Letters, vol. 42, no. 6, pp. 1694-1700 . https://doi.org/10.1002/2014GL062502
ISSN: 1944-8007
0094-8276
DOI: 10.1002/2014gl062502
Popis: Constraints on crustal and mantle structure of the Eastern part of the West African Craton have to date been scarce. Here we present results of P receiver function and SK(K)S wave splitting analyses of data recorded at International Monitoring System array TORD in SW Niger. Despite lacking in lateral coverage, our measurements sharply constrain crustal thickness (∼41 km), VP∕VS ratio (1.69 ± 0.03), mantle transition zone (MTZ) thickness (∼247 km), and a midlithospheric discontinuity at ∼67 km depth. Splitting delay times are low with an average of 0.63 ± 0.01 s. Fast directions follow the regional surface geological trend with an average of 57 ± 1 ◦ . We suggest that splitting is due to fossil anisotropic fabrics in the crust and lithosphere, incurred during the Paleoproterozoic Eburnean Orogeny, with possible contributions from the later Pan-African Orogeny and present-day mantle flow. The MTZ appears to be unperturbed, despite the proximity of the sampled region to the deep cratonic root.
Databáze: OpenAIRE
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