200 likes | 355 Views
Lecture #7: Challenges and Opportunities in Studies of Lithospheric Evolution. CAGS/SinoProbe Short Course: Lithospheric Evolution through Time April 8-12, 2011. Walter D. Mooney, Ph.D. US Geological Survey Menlo Park, California USA mooney@usgs.gov.
E N D
Lecture #7: Challenges and Opportunitiesin Studies of Lithospheric Evolution CAGS/SinoProbe Short Course: Lithospheric Evolution through Time April 8-12, 2011 Walter D. Mooney, Ph.D. US Geological Survey Menlo Park, California USA mooney@usgs.gov
Dehydration reactions in subduction zone Ranero et al., 2004
How much H2O within subducting plate? [Rüpke et al., 2006]
Faults and Fluid flow Tveranger et al., 2005
First continental crust Then: First Water out Komatiite partially melts, Basalt gets to surface, piles up. The stack sinks, partially melts when pressure high enough. Fractionation makes increasingly silica-rich magmas Density differencesallow subduction of mafic rocks. Further partial melting and fractionation makes higher silica melt that won’t subduct
Generation of Continental Crust through Time A based on Nd isotopes in shales44 B based on Pb isotopes77 C from Taylor & McLennan (1995) Hawkesworth & Kemp (2006)
Mantle Structure Source: Forte and Mitrovica (2001)
Van Heijst, Ritsema, and Woodhouse, 1999 Tomographic Model
Mantle Structure Homogeneous Heterogeneous Modified from: Meibaum and Anderson (2003)
Density model of the crust and upper mantle based on joint inversion of the new satellite gravity and seismic data. M. Kaban, M. Rothacher
Van Heijst, Ritsema, and Woodhouse, 1999 Tomographic Model
Mantle Structure Homogeneous Heterogeneous Modified from: Meibaum and Anderson (2003)
Density model of the crust and upper mantle based on joint inversion of the new satellite gravity and seismic data. M. Kaban, M. Rothacher