Now showing items 1-6 of 6

  • The effect of a shallow low viscosity zone on mantle convection and its expression at the surface of the earth 

    Robinson, Elizabeth M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1987-08)
    Many features of the oceanic plates cannot be explained by conductive cooling with age. A number of these anomalies require additional convective thermal sources at depths below the plate: mid-plate swells, the evolution ...
  • Geochemical characterization of endmember mantle components 

    Workman, Rhea K. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2005-06)
    This thesis uses trace elements and radiogenic isotope tracers to define elemental abundances in reservoirs of the Earth's mantle, including EM2 (the Enriched Mantle 2), as seen in the Samoan hotspot track, and DMM (the ...
  • Mantle plume-midocean ridge interaction : geophysical observations and mantle dynamics 

    Ito, Garrett T. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-09)
    We analyze bathymetric and gravity anomalies at five plume-ridge systems to constrain crustal and mantle density structure at these prominent oceanic features. Numerical models are then used to explore the physical ...
  • Mantle upwelling, melt generation, and magma transport beneath mid-ocean ridges 

    Magde, Laura S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-03)
    The formation of new oceanic crust is the result of a complex geodynamic system in which mantle rises beneath spreading centers and undergoes decompression melting. The melt segregates from the matrix and is focused to ...
  • Petrologic and microstructural constraints on focused melt transport in dunites and the rheology of the shallow mantle 

    Braun, Michael Geoffrey (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2004-06)
    Observations at mid-ocean ridges indicate that magmas are focused to the ridge axis by a network of porous dunites in near chemical isolation. This thesis investigates several of the outstanding questions regarding the ...
  • A search for layering in the oceanic crust 

    Collins, John A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1988-10-06)
    The results of numerous seismic refraction and reflection experiments have shown that the seismic structure of the oceanic crust can be usefully parameterized by a small number of locally horizontal layers within which ...