Premium
Probing the edge of the West African Craton: A first seismic glimpse from Niger
Author(s) -
Di Leo Jeanette F.,
Wookey James,
Kendall J.Michael,
Selby Neil D.
Publication year - 2015
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2014gl062502
Subject(s) - orogeny , craton , geology , lithosphere , crust , receiver function , mantle (geology) , discontinuity (linguistics) , transition zone , seismology , seismometer , geophysics , tectonics , mathematical analysis , mathematics
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 S K ( 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), V P / V S 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.