Coexisting Pyroxenes
نویسندگان
چکیده
منابع مشابه
Nomenclature of pyroxenes
This is the final report on the nomenclature of pyroxenes by the Subcommittee on Pyroxenes established by the Commission on New Minerals and Mineral Names of the International Mineralogical Association. The recommendations of the Subcommittee as put forward in this report have been formally accepted by the Commission. Accepted and widely used names have been chemically defined, by combining new...
متن کاملSome high-pressure pyroxenes
Microprobe analyses of Ca-rich pyroxenes crystallized in the melting ranges of a magnesian alkali basalt, a transitional basalt, an olivine tholeiite, a tholeiitic andesite, and an augite leucitite at pressures between 8 and 45 kb show complex variation. Ca-poor pyroxene precipitated only from the alkali basalt at pressures between 14 and 18 kb. Pyroxene falling near the Di-Hed join in the pyro...
متن کاملModel pyroxenes III: Volume of C2/c pyroxenes at mantle P, T, and x
Variations in unit-cell volumes of mantle minerals as functions of P and T are important parameters in the description of the interior of the Earth and the behavior of materials. Recently, Thompson and Downs (2004) presented a model for the crystal structures of pyroxenes parameterized in terms of the O3-O3-O3 angle, θ, and the oxygen radius, r. This model has proven useful in the analysis of c...
متن کاملModel pyroxenes I: Ideal pyroxene topologies
Ideal pyroxenes are hypothetical structures based on ideal closest-packed arrangements of O anions. They are modeled after observed pyroxene structures and have the general formula M2M1T2O6, where M2 and M1 represent octahedrally coordinated cations, and T represents tetrahedrally coordinated cations. An algorithm has been created to construct all possible ideal pyroxenes based on closest-packe...
متن کاملPyroxenes from Governador Valadares and Lafayette: a Nitrogen and Noble
Introduction: The Martian meteorites Governador Valadares (GV hereafter) and Lafayette (Laf. hereafter) are finds [1]. GV was found in the Minas Gerais Region (Brazil) in 1958. Laf. was recognized in the collections of Purdue University in Lafayette (Indiana) in 1931. Both belong to the group of nakhlites, which consists of 7 meteorites, including 2 from Antarctica and 2 from Northwest Africa. ...
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ژورنال
عنوان ژورنال: Geological Magazine
سال: 1969
ISSN: 0016-7568,1469-5081
DOI: 10.1017/s0016756800058027