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Geologic Investigations In The Cayman Trough And The Nature Of The Plutonic Foundation Of The Oceanic Crust, Janet B. Stroup
Geologic Investigations In The Cayman Trough And The Nature Of The Plutonic Foundation Of The Oceanic Crust, Janet B. Stroup
Geology Theses and Dissertations
A survey of the literature that deals with the gabbroic rocks believed to comprise the foundation of the oceanic crust indicates that the overwhelming majority of these rocks are recovered from escarpments associated with transform faults. The wide range of mineral and chemical compositions characterizing oceanic gabbroic rocks suggests that the lower oceanic crust is much more heterogeneous in nature than was previously suggested by the results of geophysical investigations. The examination of gabbroic rocks recovered in situ from the walls of the Mid-Cayman Rise rift valley by the submersible ALVIN not only supports the notion that oceanic gabbroic rocks …
Petrography, Mineral Chemistry And Microstructures Of Gabbros From The Mid-Cayman Rise Spreading Center, Frieda L. Malcolm
Petrography, Mineral Chemistry And Microstructures Of Gabbros From The Mid-Cayman Rise Spreading Center, Frieda L. Malcolm
Geology Theses and Dissertations
The suite of gabbroic rocks collected by the DSRV ALVIN in 1976 and 1977 from the walls of the Mid-Cayman Rise spreading center were studied in detail to provide the best available data on plutonic rocks sampled directly from the ocean floor. The rock types studied include variably deformed and altered gabbros, orthopyroxene gabbros, olivine gabbros and troctolites, and a few amphibolites. Mineral chemical analyses suggest that the various rock types are representative of a fractionation trend from magnesian troctolites through olivine and clinopyroxene gabbros to iron-enriched orthopyroxene gabbros. Within many individual samples, the primary mineral phases are apparently chemically …