Mantle velocity structure and anisotropy beneath the Gulf of Mexico and adjacent areas: constraining the geometry of the north american continental keel and possible asthenospheric flow field around it
This presentation summarizes existing seismic tomographic models obtained using surface and P- and S-waves for the GoM region. Most of the models show that the edge of the North American continent has a NW-SE trending beneath Texas, and approximately parallel to the continental margin from Louisiana to Florida. Due to the low resolution and limited amount of data used in the studies, important discrepancies understandably exist between the velocity models, such as whether there is a plume-like low-velocity structure beneath the coastal area in Texas, and if the mantle velocities beneath the GoM oceanic crust are significantly lower than those beneath adjacent continental areas. Recent shear-wave splitting measurements using data from 8 seismic stations beneath TX, OK, and AR found large (up to 1.7 s) splitting times and fast directions that are parallel to the GoM continental margin (Gao et al., 2008). One of the causes of such anisotropy is asthenospheric flow around the keel of the North American continent. This is consistent with the dominantly E-W fast directions observed in the eastern part of the northern continental margin of the GoM.
S. S. Gao and K. H. Liu, "Mantle velocity structure and anisotropy beneath the Gulf of Mexico and adjacent areas: constraining the geometry of the north american continental keel and possible asthenospheric flow field around it," 2008 Joint Meeting of The Geological Society of America, Soil Science Society of America, American Society of Agronomy, Crop Science Society of America, Gulf Coast Association of Geological Societies with the Gulf Coast Section of SEPM, Geological Society of America, Oct 2008.
Geosciences and Geological and Petroleum Engineering
Keywords and Phrases
Asthenospheric Flow; Continental Keel; Plate Motion
Article - Conference proceedings
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