The application of Tb/Ca-Tb/La abundance ratios to problems of fluorspar genesis

Möller, P.; Parekh, P. P.; Schneider, Hans-Jochen

doi:10.1007/bf00203098

Cited by 165 publications

(115 citation statements)

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“…c) Definir los procesos asociados a la mineralización: existen diferentes relaciones entre concentraciones de lantánidos para cuantificar el fraccionamiento y determinar cuando éste está asociado a procesos evolutivos del fluido, a remobilización tardía o a la asimilación del encajonante (p. ej., Möller et al, 1976;William-Jones et al, 2000;Xu et al, 2012). d) Condiciones redox del fluido: las anomalías de Eu y Ce indican las condiciones de fugacidad de oxígeno del fluido a partir del cual precipitó la fluorita (p.…”

Section: Posibles Aplicaciones De La Geoquímica De Lantánidos En Fluounclassified

“…ej., Bau et al, 2003). e) Génesis del mineral: en casos favorables la utilización de las relaciones entre concentraciones de lantánidos permite discriminar entre fluorita de origen neumatolítico, hidrotermal o sedimentario (Möller et al, 1976). f) Fines exploratorios: discriminar si la fluorita está asociada a sulfuros.…”

Section: Posibles Aplicaciones De La Geoquímica De Lantánidos En Fluounclassified

“…Möller et al, (1976) basándose en las relaciones Tb/Ca y Tb/La definen tres tipos genéticos de fluoritas: pegmatíticas (valores más altos de estas relaciones), hidrotermales (valores intermedios) y sedimentarias (valores más bajos). Según estos autores la relación Tb/La puede considerarse un índice de fraccionamiento (máximo en fluorita de cuerpos pegmatíticos y mínimo en fluorita sedimentaria) ya que el La, que es el más abundante de los lantánidos trivalentes, es extraído pronto de la solución con lo que la relación Tb/La crece en las fluoritas tardías.…”

Section: La Ce Pr Ndunclassified

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Geoquímica de lantánidos de los yacimientos de fluorita de los distritos mineros de Taxco y Zacualpan, sur de México: implicaciones sobre el origen y la evolución de los fluidos

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Morton-Bermea

et al. 2017

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We present and evaluate lanthanide contents measured by inductively coupled plasma mass spectrometry (ICP-MS) in fluorite samples from the fluorite deposits in Zacualpan and Taxco mining districts in the south of Mexico. The information is used to distinguish different generations of fluorite, to establish a correlation between mineralization episodes and the wall rock nature, and to identify postdepositional processes.The total lanthanide content of the fluorites are variable, and early- stage fluorite samples are usually enriched in LREE. The concentration of REE in fluorite is low in comparison with the volcanic and metamorphic rocks (∑REE > 100 ppm) and is generally high respect the carbonates (∑REE < 30 ppm). There is host rock influence. The higher REE concentra- tions are in fluorites hosted by volcanic rocks. The fluorite that replaced carbonate is characterized by low REE to very low concentrations. Fluorite samples associated with sulfurs are typically enriched in HREE. Nearly all fluorites show a negative Eu anomaly similar to the REE anomaly observed in the volcanic rock. Only some early stage dark, uranium rich fluorites, from la Azul deposit, have a strong positive Eu anomaly. Direct correlation between color and REE patterns is observed in some samples.In the Zacualpan mining district, only an episode of mineralization has been discriminated, where fluorite presents flat to HREE- enriched chondrite-normalized REE patterns.In the Taxco mining district and particularly in the “Mina la Azul”, multiple hydrothermal events of mineralization have been determined. The first generation of fluorite is formed by replacement of carbonates and is characterized by very low contents of lanthanides, chondrite- normalized REE patterns similar to the limestone, high strontium content and primary textures (e.g. massive fluorite and rhythmites). The second generation of fluorite is related to the entry of new fluid to the system and has higher REE concentrations, chondrite-normalized REE patterns similar to volcanic rocks, low strontium content and secondary textures (i.e. breccias, nodules). Most of the samples show a genetic relationship between fluorite and fluids of magmatic origin.

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Section: Posibles Aplicaciones De La Geoquímica De Lantánidos En Fluounclassified

Section: La Ce Pr Ndunclassified

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Geoquímica de lantánidos de los yacimientos de fluorita de los distritos mineros de Taxco y Zacualpan, sur de México: implicaciones sobre el origen y la evolución de los fluidos

Solé

Morton-Bermea

et al. 2017

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“…In case the above complexation mechanism is taken to be responsible for such fractionation in Banian, owing to REE complexation with ligands like CO 3 2-and OH -which form more stable complexes with the HREE. Therefore, LREE preferentially precipitate in the early stage, and the late stage fluid should be HREE-enriched (Möller et al, 1976). However, it is conflicting to the characteristics in Banian, where the latest stage of stibnite is enriched in LREE, especially in La element.…”

Section: Ree and Fe Mnmentioning

confidence: 99%

“…These minerals are ideal for Sm-Nd dating because they usually contain high amounts of Sm and Nd, and display enrichment of MREE and HREE, corresponding to a large variation in Sm/Nd ratios. As a result, the mechanism of LREE/HREE fractionation of hydrothermal Ca-bearing minerals becomes a considerable scientific interest, and remains controversial (Möller et al, 1976;Morgan and Wandless, 1980;Chesley et al, 1991;Bau and Möller, 1992;Schönenberger et al, 2008). Generally, carbonate shows LREE-enriched, low Sm/Nd ratio and in narrow range (0.1-0.3) (Graf, 1984).…”

Section: Introductionmentioning

confidence: 99%

Sm-Nd geochronology, REE geochemistry and C and O isotope characteristics of calcites and stibnites from the Banian antimony deposit, Guizhou Province, China

et al. 2012

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2001), a full understanding of the geodynamical setting, fluid evolution, and genesis of the epithermal antimony mineralization has been seriously hampered. Similar to other epithermal deposits (including Au, Hg, As and Tl) in southwestern China, the ore-forming ages of antimony deposits are poorly constrained due to the absence of minerals suitable for isotopic dating and the absence of ore-related intrusions in or near these deposits.According to mineral composition of ores and genesis, antimony deposits are subdivided into epithermal (e.g., Xikuangshan and Qinglong, China; Ashat, Roundnjany) and metamorphogene-hydrothermal (Woxi, China; La Lucette, France; Gravelot, South Africa) (Obolensky et al., 2007), and they are usually hosted within black shales or limestones (Williams-Jones and Norman, 1997;An and Zhu, 2010). The Sb-rich sedimentary rocks and metasedimentary rocks from Precambrian and palaeozoic constitute a possible source of Sb (Peng et al., 2003a;Fan et al., 2004;Peng and Frei, 2004 The Banian sediment-hosted antimony deposit is a medium-sized deposit located in the Dushan County, South Guizhou, China. Calcite is the dominant gangue mineral and can be divided into two types: white and pink. Pink calcite is intimately associated with mineralization. Sm-Nd dating of five white calcites yield an isochron age of 128.2 ± 3.2 Ma, with initial ε Nd = -4.3 and MSWD = 0.54, while six pink calcites yield an identical age of 126.4 ± 2.7 Ma with initial ε Nd = -6.0 and MSWD = 0.68. These new age constraints suggest that the Banian deposit formed during the late Yanshanian.Negative initial ε Nd values, C (-0.5 to -1.8), O (12.5 to 14.6) isotopic characteristics of calcites, and field observations of abundance of vuggy open spaces, all suggest significant interaction between fluid and wall rocks. Calcites are characterized by strongly LREE-depleted and MREE-and HREE-enriched (LREE/HREE = 0.11-0.61). Stibnites are LREEenriched, and MREE-and HREE-depleted (LREE/HREE = 105-500). Wall rocks are characterized by moderate LREEenriched (LREE/HREE = 6.2-12). Pink calcites are more enriched in LREE (LREE/HREE = 0.11-0.61) than white calcites (LREE/HREE = 0.11-0.23), while the concentration of HREE remains nearly constant in both. The high contents of Fe and Mn in calcites and the negative correlation between Fe+Mn (ppm) and LREE/HREE ratios suggest that the Fe-Mn impurities in calcites may dominate the enrichment of MREE and HREE in calcites from the Banian deposit.

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Cathodoluminescence Applied to Ore Geology and Exploration

Baele

Decrée

Rusk

2019

Geophysical Monograph Series

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The application of Tb/Ca-Tb/La abundance ratios to problems of fluorspar genesis

Cited by 165 publications

References 1 publication

Geoquímica de lantánidos de los yacimientos de fluorita de los distritos mineros de Taxco y Zacualpan, sur de México: implicaciones sobre el origen y la evolución de los fluidos

Geoquímica de lantánidos de los yacimientos de fluorita de los distritos mineros de Taxco y Zacualpan, sur de México: implicaciones sobre el origen y la evolución de los fluidos

Sm-Nd geochronology, REE geochemistry and C and O isotope characteristics of calcites and stibnites from the Banian antimony deposit, Guizhou Province, China

Cathodoluminescence Applied to Ore Geology and Exploration

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