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Title: A Top to Bottom Lithospheric Study of Africa and Arabia

Abstract

We study the lithospheric structure of Africa, Arabia and adjacent oceanic regions with fundamental-mode surface waves over a wide period range. Including short period group velocities allows us to examine shallower features than previous studies of the whole continent. In the process, we have developed a crustal thickness map of Africa. Main features include crustal thickness increases under the West African, Congo, and Kalahari cratons. We find crustal thinning under Mesozoic and Cenozoic rifts, including the Benue Trough, Red Sea, and East, Central, and West African rift systems. Crustal shear wave velocities are generally faster in oceanic regions and cratons, and slower in more recent crust and in active and formerly active orogenic regions. Deeper structure, related to the thickness of cratons and modern rifting, is generally consistent with previous work. Under cratons we find thick lithosphere and fast upper mantle velocities, while under rifts we find thinned lithosphere and slower upper mantle velocities. There are no consistent effects in areas classified as hotspots, indicating that there seem to be numerous origins for these features. Finally, it appears that the African Superswell has had a significantly different impact in the north and the south, indicating specifics of the feature (temperature,more » time of influence, etc.) to be dissimilar between the two regions. Factoring in other information, it is likely that the southern portion has been active in the past, but that shallow activity is currently limited to the northern portion of the superswell.« less

Authors:
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
922094
Report Number(s):
UCRL-JRNL-225868
Journal ID: ISSN 0040-1951; TCTOAM; TRN: US200803%%229
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
Tectonophysics
Additional Journal Information:
Journal Volume: 444; Journal ID: ISSN 0040-1951
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; AFRICA; RED SEA; SHEAR; THICKNESS

Citation Formats

Pasyanos, M. A Top to Bottom Lithospheric Study of Africa and Arabia. United States: N. p., 2006. Web.
Pasyanos, M. A Top to Bottom Lithospheric Study of Africa and Arabia. United States.
Pasyanos, M. 2006. "A Top to Bottom Lithospheric Study of Africa and Arabia". United States. https://www.osti.gov/servlets/purl/922094.
@article{osti_922094,
title = {A Top to Bottom Lithospheric Study of Africa and Arabia},
author = {Pasyanos, M},
abstractNote = {We study the lithospheric structure of Africa, Arabia and adjacent oceanic regions with fundamental-mode surface waves over a wide period range. Including short period group velocities allows us to examine shallower features than previous studies of the whole continent. In the process, we have developed a crustal thickness map of Africa. Main features include crustal thickness increases under the West African, Congo, and Kalahari cratons. We find crustal thinning under Mesozoic and Cenozoic rifts, including the Benue Trough, Red Sea, and East, Central, and West African rift systems. Crustal shear wave velocities are generally faster in oceanic regions and cratons, and slower in more recent crust and in active and formerly active orogenic regions. Deeper structure, related to the thickness of cratons and modern rifting, is generally consistent with previous work. Under cratons we find thick lithosphere and fast upper mantle velocities, while under rifts we find thinned lithosphere and slower upper mantle velocities. There are no consistent effects in areas classified as hotspots, indicating that there seem to be numerous origins for these features. Finally, it appears that the African Superswell has had a significantly different impact in the north and the south, indicating specifics of the feature (temperature, time of influence, etc.) to be dissimilar between the two regions. Factoring in other information, it is likely that the southern portion has been active in the past, but that shallow activity is currently limited to the northern portion of the superswell.},
doi = {},
url = {https://www.osti.gov/biblio/922094}, journal = {Tectonophysics},
issn = {0040-1951},
number = ,
volume = 444,
place = {United States},
year = {Tue Oct 31 00:00:00 EST 2006},
month = {Tue Oct 31 00:00:00 EST 2006}
}