HR: 1340h
AN: T43C-1349    [Abstracts]
TI: Compositional Variations in the Continental Lithosphere Constrained by Non-Geochemical Data
AU: * Artemieva, I M
EM: irna@swave.wr.usgs.gov
AF: US Geological Survey, 345 Middlefield Rd. MS 977, Menlo Park, CA 94025 United States
AB: A substantial part of the present knowledge on mantle composition is based on geochemical studies of locally abundant mantle-derived xenoliths. However, because xenoliths provide random, uneven, and in many areas only a sparse sampling of the Earth's deep interior, it is challenging to see if geochemical constraints on global-scale compositional variations in the mantle are consistent with modern geophysical data. Furthermore, large-scale compositional variations in the mantle reflected in seismic tomography models and mantle gravity anomalies are substantially masked by temperature anomalies. New data on the thermal regime of stable continental lithosphere (Artemieva and Mooney, 2001) allow separation of thermal and non-thermal effects in global geophysical models. A global anelastic seismic tomography model based on Rayleigh waves (Billien et al., 2000) was analyzed jointly with the new thermal model to outline regions where Qs anomalies cannot be explained by T anomalies alone. Bouguer gravity data (Kaban et al., 2003) corrected for the effect of thermal expansion were used to constrain density anomalies in subcrustal lithosphere of the continents. The results show that large variations in lithospheric composition are well correlated with regional variations in lithospheric thickness.
DE: 8180 Tomography
DE: 8120 Dynamics of lithosphere and mantle--general
DE: 8124 Earth's interior--composition and state (old 8105)
DE: 8159 Rheology--crust and lithosphere
DE: 7218 Lithosphere and upper mantle
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting