 | | Journal (article/letter/editorial) | | 377–392 Tracing the chemical evolution of primary pyrochlore from plutonic to volcanic carbonatites: the role...Agostinho Neto, Av. 4 de Fevereiro 7, 815 Luanda, Angola Earth and Ocean Sciences, School of Natural Sciences...carbonatites and the Catanda carbonatites are volcanic in origin. In Tchivira pyrochlore, zoning is poorly...inferred vacancies also increase. Pyrochlores from Catanda display complex textures. They generally have a...volcanic carbonatites. K EY WORDS : Angola, carbonatite, zonation in pyrochlore, fluorine, high field strength |  | Amores-Casals, , Melgarejo, , Bambi, , Gonçalves, , Morais, , Manuel, , Neto, , Costanzo, , Molist, (2019) Lamprophyre-Carbonatite Magma Mingling and Subsolidus Processes as Key Controls on Critical Element Concentration in Carbonatites—The Bonga Complex (Angola) Minerals, 9 (10) 601 doi:10.3390/min9100601 | Journal (article/letter/editorial) | | Concentration in Carbonatites—The Bonga Complex (Angola) Sandra Amores-Casals 1,2, *, Joan-Carles Melgarejo...Universidade Agostinho Neto, Luanda, Caixa Postal 815, Angola; aurorabambi@hotmail.com (A.B.); tonygoncalves72@hotmail...reconstruct the dynamics of the complex, the pyrochlore composition and distribution have been used as...evolution of the complex. An early Na-, F-rich pyrochlore is disseminated throughout the carbonatite plug...dykes. Crystal accumulation led to enrichment of pyrochlore crystals in the plug margins, phoscoritic units |  | | Journal (article/letter/editorial) | | Monte Verde Carbonatite–Alkaline–Agpaitic Complex (Angola) Sandra Amores-Casals 1,2, *, Antonio Olimpio Gonçalves...Universidade Agostinho Neto, Luanda, Caixa Postal 815, Angola; tonygoncalves72@hotmail.com Institut de Ciències...rare earth elements (REE) are concentrated in pyrochlore crystals in the carbonatite and alkaline breccias...and overgrown by five secondary generations of pyrochlore formed during subsolidus stages and have higher...and Ti contents. The second, third, and fourth pyrochlore generations are associated with late fluids also |  | Melgarejo, Joan C., Costanzo, Alessandra, Bambi, Aurora C.J.M., Gonçalves, Antonio O., Neto, Andrés B. (2012) Subsolidus processes as a key factor on the distribution of Nb species in plutonic carbonatites: The Tchivira case, Angola. Lithos, 152. 187-201 doi:10.1016/j.lithos.2012.06.024 | Journal (article/letter/editorial) | | species in plutonic carbonatites: The Tchivira case, Angola Joan C. Melgarejo a, Alessandra Costanzo b,⁎, Aurora...Geologia, Universidade Agostinho Neto, Luanda, Angola a r t i c l e i n f o Article history: Received...Available online 28 June 2012 Keywords: Carbonatite Pyrochlore Niobium Magmatic Hydrothermal Supergenic a b...Tchivira carbonatites contain several pyrochlore generations. Rare pyrochlore crystals, close to the fluorcalciopyrochlore...carbonates and fluorite are also common. Distinct pyrochlore compositions are characteristic for each altered |  | | Journal (article/letter/editorial) | | xxxx Keywords: Carbonatites Niobium ore deposits Pyrochlore Laterite Supergene ores a b s t r a c t This...deposit is unique with respect to the varieties of pyrochlore present; extent of replacement by other minerals;...units of carbonatite contain distinct suites of pyrochlore. Bulk rock analysis for Nb gives no indication...and physical concentration of resistant primary pyrochlore. Intense lateritization results initially in...pyrochlores, and ultimately complete decomposition of pyrochlore and formation of Nb-bearing rutile, brookite |  | | Journal (volume) | | .............................245 EG52 Platinum-group minerals in the new millennium....................[1]. Chromium-rich spinels MCr2O4 are part of a group of exciting and challenging materials that have...materials. They were studied by J.E. Shelby’s research group in Alfred University, New York, USA, according to...(2009) Appl. Clay. Sci., 43, 224-227. Apatite group minerals and their secondary alteration phases were...probably similar to that known in the nagelschmidtite group or as berlinite substitution in silicates. The determination |
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