Experimental Petrology and Geochemistry of Continental Rift Volcanics: Petrogenesis of Evolved, Alkaline Magmas

点击翻译按钮获取中文摘要

9316197 Wendlandt The proposed research involves experimental investigations of alkali basalts, demonstrated by previous geochemical and inverse-approach experimental studies to be parental to voluminous, rift-associated, volcanic occurrences. High pressure and temperature forward-approach melting experiments will be used to characterize the processes and the physical and chemical conditions within the crust necessary for the genesis of these lavas. Specific experimental objectives are: (1) to determine liquid lines of descent (fractionation paths) for melts derived by equilibrium partial melting or crystallization of alkali basalt compositions for a range of mid-crustal to upper mantle pressures and temperatures; (2) to determine the compositions of mineral phases present at these pressure and temperature conditions; (3) to characterize residual phase assemblages (cumulate lithologies); and (4) to compare compositions of phases from alkali basalt melting experiments with those documented at liquidus conditions for intermediate composition lavas. The results of the proposed experimental and analytical studies will provide a basis for evaluating polybaric paths for melt evolution at crustal conditions and enable development of integrated models for continental models for continental rift structure and evolution and for the involvement of crust in rifting processes.