Encontrados 98 documentos, a visualizar página 1 de 10
Geoquímica de feldspato, mica, berilo e turmalina e geocronologia U-Pb em monaz...
Costa, Flávia Compassi da; Cipriano, Ricardo Augusto Scholz; Marques, Rodson de Abreu; Queiroga, Gláucia Nascimento; Castro, Marco Paulo deOs pegmatitos Fazenda Concórdia e São Domingos, inseridos no contexto geotectônico do limite entre as faixas Ribeira e Araçuaí, dentro da Província Pegmatítica Oriental do Brasil, estão localizados, respectivamente, nos municípios de Mimoso do Sul e de Muqui – sul do Espírito Santo. O objetivo principal deste trabalho é estudá-los, a partir de aspectos geoquímicos, a fi m de caracterizar a evolução desses corpo...
Formation conditions and 40Ar/39Ar age of the Gem-Bearing Boqueirão Granitic Pe...
Palinkaš, Sabina Strmic; Palinkaš, Ladislav; Neubauer, Franz; Cipriano, Ricardo Augusto Scholz; Šoštaric, Sibila Borojevic; Bermanec, VladimirThe Boqueirão granitic pegmatite, alias Alto da Cabeça pegmatite, is situated in Borborema Pegmatitic Province (BPP) in Northeast Brazil. This pegmatitic province hosts globally important reserves of tantalum and beryllium, as well as significant quantities of gemstones, including aquamarine, morganite, and the high-quality turquoise-blue “Paraíba Elbaite”. The studied lithium-cesium-tantalum Boqueirão granitic...
Prospecção geoquímica de berilo variedade esmeralda na região da fazenda Bonfim...
Cipriano, Ricardo Augusto Scholz; Romano, Antônio Wilson; Belloti, Fernanda Maria; Chaves, Mario Luiz de Sá CarneiroA recente descoberta de uma nova ocorrência de esmeralda no Brasil, no Rio Grande do Norte, levou à condução de trabalhos de mapeamento geológico associados à prospecção por geoquímica de solos, visando a melhor definição do depósito. As principais estruturas geológicas e as rochas com potencial de mineralização em esmeralda apresentam-se orientadas segundo a direção geral NNESSW, correspondendo à direção de ci...
A vibrational spectroscopic study of the silicate mineral normandite – NaCa(Mn2...
Frost, Ray Leslie; López, Andrés; Theiss, Frederick L.; Cipriano, Ricardo Augusto Scholz; Romano, Antônio WilsonWe have studied the mineral normandite using a combination of scanning electron microscopy with energy dispersive spectroscopy and vibrational spectroscopy. The mineral normandite NaCa(Mn2+,Fe2+)(Ti,Nb,Zr)Si2O7(O,F)2 is a crystalline sodium calcium silicate which contains rare earth elements. Chemical analysis shows the mineral contains a range of elements including Na, Mn2+, Ca, Fe2+ and the rare earth element...
Raman and infrared spectroscopic study of kamphaugite-(Y).
Frost, Ray Leslie; López, Andrés; Cipriano, Ricardo Augusto ScholzWe have studied the carbonate mineral kamphaugite-(Y)(CaY(CO3)2(OH) H2O), a mineral which contains yttrium and specific rare earth elements. Chemical analysis shows the presence of Ca, Y and C. Back scattering SEM appears to indicate a single pure phase. The vibrational spectroscopy of kamphaugite-(Y) was obtained using a combination of Raman and infrared spectroscopy. Two distinct Raman bands observed at 1078 ...
A SEM, EDS and vibrational spectroscopic study of the clay mineral fraipontite.
Theiss, Frederick L.; López, Andrés; Cipriano, Ricardo Augusto Scholz; Frost, Ray LeslieThe mineral fraipontite has been studied by using a combination of scanning electron microscopy with energy dispersive analysis and vibrational spectroscopy (infrared and Raman). Fraipontite is a member of the 1:1 clay minerals of the kaolinite-serpentine group. The mineral contains Zn and Cu and is of formula (Cu,Zn,Al)3(Si,Al)2O5(OH)4. Qualitative chemical analysis of fraipontite shows an aluminium silicate m...
A vibrational spectroscopic study of the copper bearing silicate mineral ludden...
Frost, Ray Leslie; López, Andrés; Xi, Yunfei; Cipriano, Ricardo Augusto ScholzThe molecular structure of the copper–lead silicate mineral luddenite has been analysed using vibrational spectroscopy. The mineral is only one of many silicate minerals containing copper. The intense Raman band at 978 cm 1 is assigned to the m1 (A1g) symmetric stretching vibration of Si5O14 units. Raman bands at 1122, 1148 and 1160 cm 1 are attributed to the m3 SiO4 antisymmetric stretching vibrations. The ban...
A Raman and infrared spectroscopic study of the phosphate mineral laueite.
Frost, Ray Leslie; Cipriano, Ricardo Augusto Scholz; López, AndrésA laueite mineral sample from Lavra Da Ilha, Minas Gerais, Brazil has been studied by vibrational spectroscopy and scanning electron microscopy with EDX. Chemical formula calculated on the basis of semi-quantitative chemical analysis can be expressed as (Mn2+0.85,Fe2+0.10Mg0.05)P1.00(Fe3+1.90,Al0.10)P2.00(PO4)2(OH)2_8H2O. The laueite structure is based on an infinite chains of vertex-linked oxygen octahedra, wi...
A SEM, EDS and vibrational spectroscopic study of the tellurite mineral : sonor...
Frost, Ray Leslie; López, Andrés; Cipriano, Ricardo Augusto ScholzWe have undertaken a study of the tellurite mineral sonorite using electron microscopy with EDX combined with vibrational spectroscopy. Chemical analysis shows a homogeneous composition, with predominance of Te, Fe, Ce and In with minor amounts of S. Raman spectroscopy has been used to study the mineral sonoraite an examples of group A(XO3), with hydroxyl and water units in the mineral structure. The free tellu...
A vibrational spectroscopic study of the phosphate mineral vantasselite Al4(PO4...
Frost, Ray Leslie; Cipriano, Ricardo Augusto Scholz; Belotti, Fernanda Maria; López, Andrés; Theiss, Frederick L.We have studied the phosphate mineral vantasselite Al4(PO4)3(OH)3 9H2O using a combination of SEM with EDX and Raman and infrared spectroscopy. Qualitative chemical analysis shows Al, Fe and P. Raman bands at 1013 and 1027 cm 1 are assigned to the PO43 m1 symmetric stretching mode. The observation of two bands suggests the non-equivalence of the phosphate units in the vantasselite structure. Raman bands at 1051...