Platinum-group element resources in podiform chromitites from California and Oregon

Page, Norman J; Singer, Donald A.; Moring, Barry C.; Carlson, Carl A.; Mcdade, J. M.; Wilson, Stephen

doi:10.2113/gsecongeo.81.5.1261

Cited by 16 publications

(6 citation statements)

References 23 publications

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“…The chondrite values used are those of Naldrett and Duke (1980), while the deposit data are taken from Crocket (1981); Page et al (1982Page et al ( , 1986 and Prichard and Lord (19'90). A comparison of the results from the two deposits shows that:…”

Section: Chondrite Normalized (Cn) Datamentioning

confidence: 99%

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Remobilization of PGE in podiform chromitite in the Coolac Serpentinite Belt, Southeastern Australia

Franklin¹,

Marshall²,

Graham³

et al. 1992

Australian Journal of Earth Sciences

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Section: Chondrite Normalized (Cn) Datamentioning

confidence: 99%

“…(a) MLA dunitic host rocks (b) QOC dunitic host rocks (c) MLA chromitite pods (d) Chondrite normalized graph for chromitites from other ophiolites. Data fromCrocket, 1981;Page et al (1982Page et al ( , 1986Prichard and Lord (1990). (•) Troodos Ophiolite Complex; (A) New Caledonia; (o) Oman; (•) Dunite massif northwestern China; (A) Josephine ophiolite.…”

mentioning

confidence: 99%

Remobilization of PGE in podiform chromitite in the Coolac Serpentinite Belt, Southeastern Australia

Franklin¹,

Marshall²,

Graham³

et al. 1992

Australian Journal of Earth Sciences

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“…22 Within the ophiolitic sequences the PGE are, in general, poorly concentrated except in podiform chromitites, where minor concentrations have been reported. 19,23,25 Stratiform and podiform chromitite deposits are clearly distinguishable. Stratiform chromitite deposits are Pt-Pd-Rh-rich and have chondrite-normalized patterns that display a strong positive slope, whereas podiform chromitite patterns display a strong negative slope to B113 their chondrite-normalized patterns.…”

Section: Pge In Chromitesmentioning

confidence: 96%

Platinum-group element distribution in chromite ores from ophiolite complexes, western Turkey

Uçurum¹,

Lechler²,

Larson³

2000

Applied Earth Science

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Selected chromite mines in western Turkey (Fig. 1) were the focus for a study of platinum-group element (PGE) and Au concentrations in chromite ores and host rocks. Forty-six underground chromite mines were sampled in ten districts. The chromite is hosted in peridotite, dunite, serpentinized harzburgite and lherzolite rocks of late Jurassic to late Cretaceous age. A total of 113 ore and rock samples were collected and examined.High PGE concentrations are a feature of chromite-rich rocks worldwide in ultramafic complexes of Alpine type. 1,6,8,23,29 Knowledge of the geology and geochemistry of these deposits is, therefore, critical to understanding of the mechanism of PGE mineralization and its genesis. The study area contains numerous chromite deposits in a complex, ENE-trending suture zone between the I . zmir-Ankara ophiolite zone in the north and the Taurides platform in the south. More than 200 chromite occurrences, prospects and mines are scattered throughout the peridotites, dunites and serpentinized lherzholite-harzburgites. 10 General geological settingOphiolites of the I . zmir-Ankara zone differ from others in the study area in that they have been subjected to high-pressure, low-temperature metamorphism with the development of glaucophane, lawsonite and jadeite. 14 The ophiolitic massifs of the I . zmir-Ankara zone consist mainly of ultrabasic rocksmore than 70% harzburgite and dunites-all of which are strongly serpentinized and show a metamorphic schistosity. 24 They also include more or less recrystallized and layered metagabbros and pyroxenite; scattered dolerite dykes, which intersect all coarse-grained rocks; and crushed and dismembered volcanic and sedimentary units, all of which appear as mélanges tectonically associated with the ultrabasic masses. Finally, a discontinuously exposed blue-schist metamorphic belt immediately flanks the northern margin of the large ultrabasic massifs in the eastern part of the I . zmir-Ankara ophiolite zone. Moreover, the ophiolites are intersected by intrusive plutons, stocks and dykes of dioritic, granodioritic and tonalitic composition.The Tauric ophiolite belt, which includes ophiolites of Lycian nappes and Antalya nappes, was affected by Alpine tectonics. The ophiolite sequence at Antalya (Fig. 1) extends from harzburgitic tectonites to the dyke complex and includes a well-developed cumulate sequence. All massifs in the Tauric ophiolite belt are allochtonous and belong to a complex system of nappes, thrust over the Tauric calcareous axis. The oldest tectonic emplacement is dated as late Cretaceous and the first post-tectonic transgressive deposits are Palaeocene. 14 The ophiolites of the Lycian nappes ( Fig. 1) are mainly peridotite. They cover more than 3000 km 2 with a thickness of between 1 and 2 km. The lithology of this giant ultramafic mass is known to be extremely monotonous. In the bay of Marmaris and the Datça peninsula the whole mass is a complex of dunite-harzburgite-orthopyroxenite. Most of the harzburgites are folded, foliated and lineated tecton...

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“…Gold appears to have been derived from goldbearing quartz veins, and chromite and platinumgroup minerals from podiform chromite deposits in the ultramafic portion of ophiolite complexes in the western Paleozoic and Triassic terrane (Irwin, 1972;Page et al, 1986). Mr.…”

Section: Sourcementioning

confidence: 99%

Recent Discoveries of Large Diamonds in Trinity County, California

Kopf¹,

Hurlbut²,

Koivula³

1990

Gems & Gemology

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During the 1 9 8 0~~ Edgar J. Clarlz, a retired geologist and miner, recovered four large diamonds, three of record-breaking size, in northern California. According to Mr. Clarlz, all were found on Hayfork Creek, in the Trinity County portion of the Klamath Mountains. The first and smallest, found in the early 1980s, weighed 3.90 ct. Burton Westman, a consulting geologist in Boulder City, Nevada, examined the stone and confirmed its identity as diamond. Mr. Clarlz has since named the diamond "Jeopardy."

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Platinum-group element resources in podiform chromitites from California and Oregon

Cited by 16 publications

References 23 publications

Remobilization of PGE in podiform chromitite in the Coolac Serpentinite Belt, Southeastern Australia

Remobilization of PGE in podiform chromitite in the Coolac Serpentinite Belt, Southeastern Australia

Platinum-group element distribution in chromite ores from ophiolite complexes, western Turkey

Recent Discoveries of Large Diamonds in Trinity County, California

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