T51G-3006
Mantle Flow Implications across Easter and Southern Africa from Shear Wave Splitting Measurements
Friday, 18 December 2015
Poster Hall (Moscone South)
Cristo Ramirez, Pennsylvania State University Main Campus, University Park, PA, United States, Andrew Nyblade, Penn St Univ, University Park, PA, United States, Brian C Bagley, University of Minnesota Twin Cities, Minneapolis, MN, United States, Gabriel Daudi Mulibo, University of Dar es Salaam, Dar es Salaam, Tanzania, Fred Tugume, Geological Survey Department, Entebbe, Uganda, Michael Edward Wysession, Washington Univ, Saint Louis, MO, United States, Douglas Wiens, Washington University in St Louis, Department of Earth and Planetary Sciences, St. Louis, MO, United States and Mark van der Meijde, University of Twente, Enschede, Netherlands
Abstract:
In this study, we present new shear wave splitting results from broadband seismic stations in Botswana and Namibia, and combine them with previous results from stations in Kenya, Uganda, Tanzania, Malawi, Zambia, South Africa, Mozambique, Zimbabwe, and Angola to further examine the pattern of seismic anisotropy across southern Africa. The new results come from stations in northern Namibia and Botswana, which help to fill in large gaps in data coverage. Our preliminary results show that fast polarization directions overall trend in a NE orientation. The most noticeable measurements that deviate from this pattern are located around the Archean Tanzania Craton in eastern Africa. The general NE pattern of fast polarization directions is attributed to mantle flow linked to the African superplume. Smaller scale variations from this general direction can be explained by shape anisotropy in the lithosphere in magmatic regions in the East African rift system and to fossil anisotropy in the Precambrian lithosphere.
