Rare-earth mineral deposits of the Mountain Pass District, San Bernardino County, California, with a foreword on history of the discovery at Mountain Pass, California

Olson, Jerry Chipman; Shawe, Daniel R.; Pray, Lloyd C.; Sharp, William N.

doi:10.3133/pp261

Cited by 46 publications

(61 citation statements)

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“…A notable feature of synchysite-(Ce) is the higher amount of Y, compared to other carbonatites worldwide, where yttrium has not been observed: Mountain Pass, California, U.S.A. (Olson et al 1954, Castor 2008, Kangankunde, Malawi (Wall & Mariano 1996), BayanObo, Inner Mongolia (Chao et al 1997) and Yuzhnoe and Arshan, Russia (Ripp et al 2000).…”

Section: Composition Of the Mineralsmentioning

confidence: 99%

Hydrothermal Ree Mineralization in the Amba Dongar Carbonatite Complex, Gujarat, India

Doroshkevich¹,

Viladkar²,

Рипп³

et al. 2009

The Canadian Mineralogist

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We have studied two groups of overprinted (altered) carbonatites at Amba Dongar, India: weakly overprinted and strongly overprinted. The mineral association of quartz, florencite-(Ce), strontianite, barite and sparse bastnäsite -parisite -synchysite typical of weakly overprinted carbonatites shows evidence of a high activity of OH -, (SO 4 ) 2-, Al and Si in the fluid. Later, the fluid was characterized by an increased activity of F -, (SO 4 ) On the basis of field observations, two phases of alvikite dikes have been recognized. Phase I is coeval with the main intrusion of sövite, and cross-cuts the sandstone, carbonatite breccia and pre-carbonatite basalt, whereas phase-II dikes were emplaced later. Ankeritic carbonatite, which is younger than the calciocarbonatite, invades sövite at several outcrops in the form of dikes and plugs of varying size. The ankeritic carbonatite occurs in three distinct phases. The first phase consists of thin dikes intruding sövite and fenite; the second phase forms large plugs within the sövite ring-dike, whereas the last phase is characterized by high radioactivity owing to the high abundances of cerite, monazite-(Ce), and thorite (Viladkar 1996). Veins of sideritic carbonatite, which are found in ankeritic carbonatites, also contain cerite, monazite and thorite. Locally, the total REE content is well above 15 wt.% (Viladkar 1996). The carbonatite activity appears to have ended with fluorite mineralization.

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Section: Composition Of the Mineralsmentioning

confidence: 99%

Hydrothermal Ree Mineralization in the Amba Dongar Carbonatite Complex, Gujarat, India

Doroshkevich¹,

Viladkar²,

Рипп³

et al. 2009

The Canadian Mineralogist

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“…Metasomatically formed allanite however, has only rarely been reported : in limestone skarns by Rudashevskiy (1969) and by Pavelescu and Pavelescu (1972), in regional metamorphic calc-silicate rocks by Sargent (1964). Allanite occurs also in carbonate veins of the Mountain Pass district, California (Olson et al 1954). …”

Section: Introductionmentioning

confidence: 99%

Zirconolite, allanite and hoegbomite in a marble skarn from the Bergell contact aureole: implications for mobility of Ti, Zr and REE

Gieré¹

1986

Contr. Mineral. and Petrol.

106

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Abstract. Zirconolite, allanite and hoegbomite are present as accessory phases in a metasomatically altered spinel-calcite-marble from the contact with the Bergell intrusives (Switzerland/Italy). Textural relationships indicate a stepwise alteration of spinel to 1) hoegbomite or corundum + magnetite, 2) margarite and 3) chlorite. Replacement of spinel by hoegbomite can be described by the substitution 1.94(M g2 + F e2 + z n 2 + m n 2+ ca2+),,T•4+ + 0.12(OH ) where Al' and Fe' are held constant. The average composition of the Bergell hoegbomites is given by the formula Fe u 7 Mg0.69 Zn 0.04 Ti 0.17 A1 3.94 F4.+060 7.98( OH )0.02 and seems to be imposed by the composition of pre-existing spinel. During the first two steps of spinel alteration, calcite was replaced by anorthite + phlogopite, and the rare earth element(REE)-bearing minerals zirconolite, allanite and sphene were formed. Allanites have characteristic chondrite-normalized REE patterns with enrichment in the light REE. The zirconolite patterns show a marked increase in concentration from La to Ce, followed by an almost constant section. Sphene lacks detectable La, and its REE patterns vary from grain to grain. Contemporaneous formation of phlogopite, REE-bearing minerals and hoegbomite during replacement of the spinel-calcite-marble indicates that the metamorphic fluid introduced potassium along with REE and other high valence cations (Ti', Zr4+ , U4+, Th', Nb', Y 3+ ) possibly as polynuclear complexes. The abundance of fluorine-bearing phlogopite and fluor-apatite as well as their close association with REE-bearing minerals and hoegbomite suggests F -and P01 -as likely ligands for complexing of the above mentioned elements.

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“…The Mountain Pass deposit shares features with other carbonatites in the world: (1) textural and structural features that support igneous intrusive origin (Olson et al 1954); (2) associated alkalirich fenitic alteration; and (3) low 87 Sr/ 86 Sr (Powell, Hurley, and Fairbairn 1966;E. DeWitt, personal communication).…”

Section: Origin Of Depositsmentioning

confidence: 93%

“…Like the Bayan Obo ore, the Mountain Pass carbonatite ore has extreme LREE enrichment with no europium anomalies ( Figure 4) and low 87 Sr/ 86 Sr. As at Bayan Obo, alkali-rich alteration is associated with the Mountain Pass carbonatite; in both areas, alteration assemblages include sodic amphibole and potash feldspar (Olson et al 1954;Drew, Meng, and Sun 1990). The Bayan Obo and Mountain Pass deposits are both enriched in barium and fluorine (Wu, Yuan, and Bai 1996;Castor and Nason 2004).…”

Section: Origin Of Depositsmentioning

confidence: 99%

International rare earth metals market and processing technologies: State-of-the-art and future prospects

Yushina¹,

Petrov²,

Grishaev³

et al. 2015

gzh

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Rare-earth mineral deposits of the Mountain Pass District, San Bernardino County, California, with a foreword on history of the discovery at Mountain Pass, California

Cited by 46 publications

References 0 publications

Hydrothermal Ree Mineralization in the Amba Dongar Carbonatite Complex, Gujarat, India

Hydrothermal Ree Mineralization in the Amba Dongar Carbonatite Complex, Gujarat, India

Zirconolite, allanite and hoegbomite in a marble skarn from the Bergell contact aureole: implications for mobility of Ti, Zr and REE

International rare earth metals market and processing technologies: State-of-the-art and future prospects

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