EPIDOTE-BEARING CALC-ALKALIC GRANITOIDS IN NORTHEAST BRAZIL
نویسندگان
چکیده
منابع مشابه
Merguerian, Charles, 1985c, Tectonic significance of mylonitic Paleozoic gneissic granitoids in the Shoo Fly Complex, Tuolumne County, California
Paleozoic gneissic granitoids are an important lithologic component of the Shoo Fly Complex of the central Sierra Nevada, California. Field relations, petrographic, and geochemical studies indicate that the gneisses were originally intruded as a seri.es of plutons ranging from gabbro (oldest) to granite and granodiorite (median age) to syenite (youngest) with the granitoid types predominating. ...
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We recognize eight types of ferroan granitoid that can be distinguished on the basis of major element chemistry.These include alkalic granitoids that may be metaluminous or peralkaline, alkali-calcic granitoids that may be metaluminous, peraluminous or peralkaline, calc-alkalic granitoids that may be metaluminous or peraluminous, and rare calcic ferroan granitoids. These granitoids may form by ...
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The Proterozoic eon is characterized by an unusual abundance of ferroan feldspathic rocks that range in composition from granite to quartz syenites to feldspathoid-bearing syenites. Three associations of ferroan rocks may be recognized on the basis of major element compositions: (1) metaluminous alkalic to alkali-calcic syenites and granites associated with anorthosites and iron-rich basaltic r...
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Five calc-alkaline plutons; Um Tagher, Abu Zawil, Um Gidri, Um Anab and El Ghuzah, in the northern Eastern Desert of Egypt were subjected to petrographic and mineralogical investigations. They are composed of varying proportions of quartz + plagioclase +potash feldspar+ biotite + hornblende± epidote ± calcite + titanite +magnetite + apatite and zircon. Electron microprobe analyses of coexisting...
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A pilot program was implemented in 1975 in rural areas surrounding the city of Fortaleza in northeastern Brazil to improve maternal and infant health care using previously untrained local personnel and limited resources. The ongoing program has been unusual, in that not only have traditional birth attandants received basic training, but they have overseen deliveries in small maternity centers ...
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ژورنال
عنوان ژورنال: Revista Brasileira de Geociências
سال: 1990
ISSN: 0375-7536
DOI: 10.25249/0375-7536.199088100