Scientific Value of Coring the Proposed Southern Appalachian Research Drill Hole (1987) / Chapter Skim
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CHEMICAL AND ISOTOPIC COMPOSITION OF ROCKS
CHEMICAL AND ISOTOPIC COMPOSITION OF ROCKS
Pages 10-15
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From page 10... ...
Any information obtained from lunar samples was extremely valuable, even for samples that could not be placed into accurate geologic context. The lunar sampling program and the continental drilling program are very dissimilar, and have vastly different geochemical sampling requirements.
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From page 11... ...
Thus, a good case can be made that continuous core is better for most geochemical sampling than the best surface outcrops. For many petrological purposes, it is important to make accurate major and trace element analyses of whole-rock samples.
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From page 12... ...
MAJOR ELEMENT GEOCHEMISTRY Characterization of igneous rocks recovered from continental drilling requires accurate knowledge of major element compositions. Such information is vital to correlations of metamorphic rocks beneath the drill site with those exposed elsewhere at the surface.
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From page 13... ...
Trace element studies will be critical in establishing correlations between geologic units in the southern Appalachian hole and surface outcrops. Carbonate rocks beneath the sole of the thrust brought up as lenses in the Brevard fault zone, for example, may be correlative with rocks exposed to the west in the Valley and Ridge province.
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From page 14... ...
For example, isotopic studies of igneous rocks within a tectonostratigraphic terrane, now present as a thin thrust sheet, and very likely to indicate whether that terrane originally formed on oceanic or continental crust; if continental, the age of the crust might also be obtained. Isotopic studies should be carried out on igneous rocks from all terranes encountered in the southern Appalachian drill hole in order to test hypotheses of terrane origins and indicate the nature of underlying crustal types.
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From page 15... ...
The character of protoliths of metasedimentary rocks, such as those below the master sole thrust, may be elucidated. Stable isotope data will also contribute to identifying crustal or mantle components of igneous rocks encountered in the hole.
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