DESCRIPTIVE MODEL OF PODIFORM CHROMITE By John P. Albers APPROXIMATE SYNONYM Alpine type chromite (Thayer, 1964). DESCRIPTION Podlike masses of chromitite in ultramafic parts of ophiolite complexes (see fig. 20). GENERAL REFERENCE Dickey (1975). GEOLOGICAL ENVIRONMENT Rock Types Highly deformed dunite and harzburgite of …
The podiform chromities occur in a well-preserved mantle sequence consisting of lherzolite-harzburgite with abundant lenses of olivine dunite. The podiform chromitite deposits are common as small and irregularly shaped masses in the Southeastern Desert (SED) of Egypt. The podiform chromities exhibit a wide range of compositions from high Cr to high Al varieties. …
We have identified 1,124 individual podiform chromite deposits, based on a 100-meter spatial rule, and have compiled them in a database. Of these, 619 deposits have been used to create three new grade and tonnage models for podiform chromite deposits. The major podiform chromite model has a median tonnage of 11,000 metric tons and a mean grade ...
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Podiform chromitites in the mantle sections of ophiolites belong to either high-Cr (metallurgical) or high-Al (refractory) varieties. Their highly variable compositions are reflected by different Cr#s [100Cr / (Cr + Al)] and Cr 2 O 3 and Al 2 O 3 contents of the chromite, falling in the boninitic and MORB fields, respectively. Parental magmas of high-Cr chromitites have higher …
Podiform chromite deposits containing chromite. Name of deposit. Deposit type. State or Province. Country. Blow-Me-Down. minor podiform chromite. Newfoundland. Canada.
Abstract. Podiform chromite deposits are lenticular, chromite-rich autoliths in deformed dun-ites and harzburgites of ophiolite complexes. The ophiolite association is assumed to be created along accreting plate boundaries in the oceanic lithosphere. It is suggested that podiform chromite deposits form as magmatic cumulates in elongate magma ...
Podiform chromite deposits occur in peridotite and mafic complexes of alpine type, and are tabular, pencil-shaped, or irregular in form. In contrast with stratiform deposits, whose textures and structures reflect crystal settling and suggest analogies with sedimentary rocks, the textures of podiform deposits reflect extensive flowage, under magmatic conditions, as a stiff crystal …
The minor podiform chromite model has a median tonnage of 100 metric tons and a mean grade of 43 percent Cr 2 O 3. The banded podiform chromite model has a median tonnage of 650 metric tons and a mean grade of 42 percent Cr 2 O 3. Observed frequency distributions are also given for grades of rhodium, iridium, ruthenium, palladium, and platinum.
Most podiform chromite deposits are found in dunite or peridotite near the contact of the cumulate and tectonite zones in ophiolites. We have identified 1,124 individual podiform chromite deposits, based on a 100-meter spatial rule, and have compiled them in a database.
The purpose of this report is to present the data used to develop indices of soil and ecosystem quality associated with mineralized terranes (areas enriched in metal-bearing minerals), specifically podiform chromite, quartz alunite, and Mo/Cu porphyry systems.
Location and characteristics of podiform chromite deposits worldwide Download . Web Resource Visit page . Web Resource Visit page . Web Resource Visit page . Dates. Metadata Date: March 7, 2018: Metadata Created Date: March 22, 2021: Metadata Updated Date: March 22, 2021: Reference Date(s) January 1, 2012 (publication) ...
Exploration models for podiform chromite in the Medford-Coos Bay quadrangles must consider the facts that (1) one deposit occurs for every 5 km 2 of ultramafic outcrop; similarly for a 5 km 3 volume, and (2) the average deposit has a tonnage of 206 tonnes, a volume of 8.9 m 3 and a grade between 43 and 51 percent Cr2O3.
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When these results are applied to the lithospheric mantle, podiform chromite deposits may form when droplets of olivine-normative high-pressure, low-viscosity melt mingle with siliceous low-pressure, more viscous melt in shallow magma conduits. It is inferred from the experimental analogue that chromite only nucleates in the melt where γSL is ...
Podiform chromite deposits. Location and characteristics of 1,124 individual podiform chromite mineral deposits, with grade and tonnage models for chromium as well as several related elements. View. Show in a web browser window: Global. Show in …
Podiform chromite deposits occur in peridotite and mafic complexes of alpine type, and are tabular, pencil-shaped, or irregular in form. In contrast with stratiform deposits, whose textures and ...
Stratiform, Podiform, and Beach Sands. Small amounts of chromite are found in many types of rock. However, chromite deposits that are large enough for mining are generally found in: 1) stratiform deposits (large masses of igneous rock such as norite or peridotite that slowly crystallized from subsurface magma); 2) podiform deposits (serpentines and other …
Монгол улсын хэмжээнд 1:500, 1:1000, 1:2000, 1:5000–ны масштабтай байр зүйн болон дэвсгэр зураг зохиох, шинэчлэх, хэвлэх үйл ажиллагаанд байгууллага, аж ахуйн…
Box plots of deposit tonnages by podiform chromite deposit subtypes. Dots are values for individual deposits. Median value is the center line of box, 25th and 75th quartiles are top and bottom of...
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Chromite is a crystalline mineral composed primarily of iron(II) oxide and chromium(III) oxide compounds. It can be represented by the chemical formula of FeCr 2 O 4.It is an oxide mineral belonging to the spinel group.The element magnesium can substitute for iron in variable amounts as it forms a solid solution with magnesiochromite (MgCr 2 O 4). A substitution of the element …
Most podiform chromite deposits are found in dunite or peridotite near the contact of the cumulate and tectonite zones in ophiolites (Rasilainen et al., 2016; Mosier et al., 2012.
Podiform chromite deposits, database and grade and tonnage models: USGS Scientific Investigations Report 2012-5157 by Dan L. Mosier, Donald A. Singer, et al.. Click here for the lowest price! Paperback, 9781288851416, 1288851413
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I have oversaturated the immiscible system SiO 2 Al 2 O 3 FeO K 2 O with FeCr 2 O 4 to study the fractionation of chromite between conjugate siliceous and fayalitic melts. Although both melts are oversaturated with chromite, chromite only nucleates in the fayalite-rich melt where the crystal/melt interfacial energy (γ SL) is lowest.In less than three days at …
Chromite in small podiform deposits has 100 Cr/(Cr + Al) ratios of 62–85, which are consistent with crystallization from such melts. Most of the chromite composition parameters are similar to those of ophiolite deposits except for the high ferric iron contents (2.77–8.95 wt% Fe 2 O 3). Such enrichment is a feature of chromite from island ...
Chromite (Cr) occurs exclusively in mafic and ultramafic igneous rocks (Papp and Lipin, 2006).Although some Cr-based minerals such as crocoite (PbCrO 4), vauquelinite (Pb 2 Cu[CrO 4][PO 4]), uvarovite (Ca 3 Cr 2 [SiO 4] 3), and merumite (4(Cr,Al) 2 O 3 ·3H 2 O) are well known, chromite (FeCr 2 O 4) is the only one that is a commercially recoverable source of Cr …
Exploration models for podiform chromite in the Medford-Coos Bay quadrangles must consider the facts that (1) one deposit occurs for every 5 km 2 of ultramafic outcrop; similarly for a 5 km 3 volume, and (2) the average deposit has a tonnage of 206 tonnes, a volume of 8.9 m 3 and a grade between 43 and 51 percent Cr2O3. Citation Information
DOI: 10.3133/SIR20125157 Corpus ID: 54921934; Podiform chromite deposits--database and grade and tonnage models @article{Mosier2012PodiformCD, title={Podiform chromite deposits--database and grade and tonnage models}, author={Dan L. Mosier and Donald A. Singer and Barry C. Moring and John P. Galloway}, journal={Scientific Investigations Report}, year={2012} }
PDF | On Aug 27, 2014, Mosier and others published podiform chromite locations | Find, read and cite all the research you need on ResearchGate