Rare earth elements and hydrothermal ore formation processes

Lottermoser, Bernd G.

doi:10.1016/0169-1368(92)90017-f

Cited by 240 publications

(88 citation statements)

References 129 publications

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“…Compared to the Aljustrel jaspers, in addition to higher apparent temperatures of formation, the Masa Valverde cherts show a positive Eu anomaly and undepleted Ce concentrations. The positive Eu anomaly may reflect higher concentration in this element in hotter hydrothermal fluids, as suggested by Lottermoser (1992). areas with strong negative Eu anomalies (evidence of channel-ways used by high temperature mineralising fluids) .…”

Section: Siliceous Exhalitesmentioning

confidence: 99%

Mineralogy and geochemistry of the Masa Valverde blind massive sulphide deposit, Iberian Pyrite Belt (Spain)

Ruiz¹,

Arribas²

2002

Ore Geology Reviews

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Masa Valverde is a blind, volcanic-hosted massive sulphide deposit recently discovered in the Spanish sector of the Iberian Pyrite Belt (IPB). The deposit is more than 1 km long and is located at depths between 400 and 850 m, in direct spatial association with a residual gravimetric anomaly. The ore body is concealed beneath Culm sedimentary rocks which cover the westem extension of a Hercynian age anticline, a few kilometers west of an area where older massive sulphide workings existed. The Masa Valverde deposit consists of two main ore bodies composed dominantly of massive and banded pyrite which are hosted by a volcano-sedimentary sequence made up of felsic tuffs interlayered with shale, siliceous exhalite and radiolarian chert. The abundance of sedimentary host rocks to the deposit is a feature shared by other large massive sulphide deposits in the eastem sector of the IPB and is interpreted as significant with respect to the origin of the deposit (a break in volcanic activity). The thickness of the upper massive sulphide orebody varies between a few meters and 70 m, and it consists of lenses and blankets of massive sulphides with interbedded tuff and shale and occasionally stockwork zones. The lower orebody is smaller and thinner than the upper one, but this may be due to incomplete drilling. Two types of stockwork occur beneath the massive sulphide bodies, the more common type consists of irregular and anastomosing sulphide veinlets and irregular blebs formed by replacement. Stockwork with cross-cutting, generally straight-sided, sulphide veins is, by contrast, suggestive of formation by hydraulic fracturing. The mineralogy and alteration processes of the ore and host rocks at Masa Valverde are analogous to those of other IPB massive sulphides. The average temperature of formation of the components of the ore zones estimated on the basis of chlorite thermometry are as follows: siliceous exhalites (290 OC), massive sulphides (325 OC) and stockworks (305 OC). Rare earth element measurements indicate that the lowest metal concentrations occur in chloritites, which occasionally host Cu-rich stockwork and are characterised by a strongly negative Eu anomaly. By contrast, rocks hosting the sulphide lenses, where silicification, sericitization and carbonatization are more intense, are enriched in LREE. Two main stages of hydrothermal activity are suggested for the Masa Valverde deposit. During an early stage, ore fluids would have discharged onto the sea floor resulting in the deposition of pyrite with sphalerite and galena. Later on, with continued input of high temperature fluids (290 to 315 OC), chalcopirite precipitated, especially in the stockworks and at the base of the sulphide lenses. At Masa Valverde, this late Cu-rich hydrothermal event would have produced an ascending Cu-front which overpassed the stockwork zone and reached a higher temperature (325 OC) at the base of the massive sulphide lenses. The combination of geological, mineralogical and geochemical features of the Masa Valverde deposit p...

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Section: Siliceous Exhalitesmentioning

confidence: 99%

Mineralogy and geochemistry of the Masa Valverde blind massive sulphide deposit, Iberian Pyrite Belt (Spain)

Ruiz¹,

Arribas²

2002

Ore Geology Reviews

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“…ej., Irving, 1978), es decir, a sistemas de alta temperatura y presión y no a sistemas que se forman en condiciones más superficiales. Por otra parte, como muchos sulfuros y óxidos no son buenos huéspedes para los lantánidos (Lottermoser, 1992), los estudios sobre la distribución de estos elementos en yacimientos hidrotermales se limitan a los minerales de ganga como son la calcita, la fluorita y la barita.…”

Section: Introductionunclassified

“…ej., Lottermoser, 1992). La variación de uno de estos parámetros, puede producir una desestabilización de los complejos químicos que transportan a los lantánidos y determinar a su vez modificaciones importantes en los patrones.…”

Section: Introductionunclassified

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

revmexcg

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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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“…al., 1984;Giere, 1986;Whitford et al, 1988;Lottermoser, 1992;Parr, 1992;Wood and Williams-Jones, 1994;Bierlein, 1995;Bierlein et al, 1999). The mobility of trace elements in altered host-rocks, and their distribution in host rocks and ores may provide constraints regarding the physico-chemical characteristics of the ore-bearing fluids, and may contribute to understanding the ore-forming processes (Lottermoser, 1992).…”

Section: Rare Earth Elements and High Field Strength Elementsmentioning

confidence: 99%

Geochemistry of the sediment-hosted disseminated gold deposits in Southwestern Guizhou Province, China /

Bao¹

2001

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Rare earth elements and hydrothermal ore formation processes

Cited by 240 publications

References 129 publications

Mineralogy and geochemistry of the Masa Valverde blind massive sulphide deposit, Iberian Pyrite Belt (Spain)

Mineralogy and geochemistry of the Masa Valverde blind massive sulphide deposit, Iberian Pyrite Belt (Spain)

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

Geochemistry of the sediment-hosted disseminated gold deposits in Southwestern Guizhou Province, China /

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