Crustal thickness and Vp/Vs ratio in NW Namibia from receiver functions: Evidence for magmatic underplating due to mantle plume‐crust interaction. Issue 9 (14th May 2015)

• Record Type: Journal Article
• Authors: Heit, Benjamin; Yuan, Xiaohui; Weber, Michael; Geissler, Wolfram; Jokat, Wilfried; Lushetile, Bufelo; Hoffmann, Karl‐Heinz
• Is Part Of: Geophysical research letters. Volume 42:Issue 9(2015:May)
• Page Start: 3330
• Page End: 3337
• Publication Date: 2015-05-14
• Subjects: Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2015GL063704
• Languages: English
• ISSNs: 0094-8276

Abstract

<abstract abstract-type="main" id="grl52916-abs-0001"> <title>Abstract</title> <p>A seismological network was operated at the junction of the aseismic Walvis Ridge with the northwestern Namibian coast. We mapped crustal thickness and bulk <italic>V_p</italic>/<italic>V_s</italic> ratio by the H‐k analysis of receiver functions. In the Damara Belt, the crustal thickness is ~35 km with a <italic>V_p</italic>/<italic>V_s</italic> ratio of &lt;1.75. The crust is ~30 km thick at the coast in the Kaoko Belt. Strong variations in crustal thickness and <italic>V_p</italic>/<italic>V_s</italic> ratios are found at the landfall of the Walvis Ridge. Here and at ~150 km northeast of the coast, the crustal thickness increases dramatically reaching 44 km and the <italic>V_p</italic>/<italic>V_s</italic> ratios are extremely high (~1.89). These anomalies are interpreted as magmatic underplating produced by the mantle plume during the breakup of Gondwana. The area affected by the plume is smaller than 300 km in diameter, possibly ruling out the existence of a large plume head under the continent during the breakup.</p> </abstract>