| | Journal (article/letter/editorial) | GEM-MINERALIZED AND “HYBRID” ANJANABONOINA GRANITIC PEGMATITE, CENTRAL MADAGASCAR: A RECORD OF MAGMATIC AND... Moro 5, I–00185 Roma, Italy Abstract The Anjanabonoina rare-element-enriched granitic pegmatite dikes...dikes, located about 40 km southwest of Betafo, in central Madagascar, are emplaced in a complex environment...strongly zoned and, in the mineralized area called Sarodivotra, they show a rich paragenetic assemblage in which...spodumene, and hambergite) typical of much of the Anjanabonoina dike. Large crystals of pyrochlore of the first | | | Journal (article/letter/editorial) | earmark of NYF-type granitic pegmatites? Clues from hybrid pegmatites in Madagascar Robert F. Martin,1,* Caterina...is considered an earmark of evolved granitic pegmatites of NYF type. Elements of an explanation of the...a study of the classic Anjanabonoina “hybrid” granitic pegmatite in Madagascar. The NYF assemblages there...there and at the Sakavalana and Anjahamiary pegmatites contain magmatic U- and Th-rich accessory phases...perthite. The amazonitic microcline perthite at Anjanabonoina has a δ18O value above 15‰, and that at Sakavalana | | | Journal (article/letter/editorial) | (2005) THE PATTERNS OF ENRICHMENT IN FELSIC PEGMATITES ULTIMATELY DEPEND ON TECTONIC SETTING Robert...Abstract The classification scheme of granitic pegmatites currently in vogue is largely an offshoot of...it to pegmatites in silica-saturated and -undersaturated systems. Small-scale bodies of pegmatites are...felsic magma. We consider LCT (Li–Cs–Ta-enriched) pegmatites to be members of orogenic (calc-alkaline suites)...subduction setting; in contrast, NYF (Nb–Y–F-enriched) pegmatites, are affiliated with anorogenic suites, formed | | | Journal (article/letter/editorial) | 165 THE LATE-STAGE MINIFLOOD OF Ca IN GRANITIC PEGMATITES: AN OPEN-SYSTEM ACID-REFLUX MODEL INVOLVING PLAGIOCLASE...Abstract As Richard H. Jahns used to say, granitic pegmatites are prone to stew in their own juice. The early...country rock, mostly from the apical parts of zoned pegmatites. There, it interacts with plagioclase in any...original cavities and creates new ones. Miarolitic pegmatites of either NYF and LCT affiliation contain clear...ramifications concerning the economic aspects of granitic pegmatites. In particular, the cycles of hydrothermal enrichment |
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