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ferritchromite

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Journal Article
Published: 01 February 2013
Mineralogical Magazine (2013) 77 (1): 117–136.
...B. M. Saumur; K. Hattori Abstract Ferritchromite is rarely reported in forearc mantle peridotites. This contribution describes ferritchromite alteration and zoned Cr-spinel in serpentinites from the Rio San Juan Complex in the Dominican Republic. These rocks originated from the forearc mantle...
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Journal Article
Published: 01 October 2009
American Mineralogist (2009) 94 (10): 1459–1467.
... of disseminated to massive chromitite mineralization. In mélange environments, intense metamorphic alteration above 300 °C leads to major changes in chromite chemistry and to the growth of secondary phases such as ferritchromite and chromian-chlorite. Based on textural and chemical analyses, mélange-hosted...
FIGURES
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Journal Article
Published: 01 April 1988
American Mineralogist (1988) 73 (3-4): 383–388.
...Pouyan Shen; Shyh-Lung Hwang; Hao-Tsu Chu; Ruey-Chang Jeng Abstract Electron-diffraction studies indicate that the deviation from spinel stoichiometry in “ferritchromit” from the podiform chromitite deposit at Heng-Chun in southern Taiwan can be reasonably explained by the topotaxial intergrowth...
Journal Article
Published: 01 April 1987
American Mineralogist (1987) 72 (3-4): 413–422.
...-magnetite rock, and in ultramafite, adjacent blackwall zones, and the surrounding metapelite. From core to edge, four zones can be identified in some of the chromite grains: a central transparent zone that is a solid solution along the gahnite-chromite join, a two-phase “ferritchromit” zone, a narrow...
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A chemical transect through spinel (Spl), ferritchromite (FC), and Mt3 magnetite along fractures.
Published: 01 January 2012
Fig. 9 A chemical transect through spinel (Spl), ferritchromite (FC), and Mt 3 magnetite along fractures.
Image
Highly porous ferritchromite replacement of a chromite grain surrounded by chromian-chlorite with serpentine relics. Fe-Chr = ferritchromite, Cr-Chl = chromian-chlorite, Atg = antigorite.
Published: 01 October 2009
F igure 3. Highly porous ferritchromite replacement of a chromite grain surrounded by chromian-chlorite with serpentine relics. Fe-Chr = ferritchromite, Cr-Chl = chromian-chlorite, Atg = antigorite.
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Spinel stability limits for ferritchromite calculated for equilibrium with olivine of composition Fo90 at 500, 550, and 600 °C (Sack and Ghiorso 1991). Selected chemical analyses of ferritchromite cores from the Kalkan chromitite are shown in diamonds.
Published: 01 October 2009
F igure 8. Spinel stability limits for ferritchromite calculated for equilibrium with olivine of composition Fo 90 at 500, 550, and 600 °C ( Sack and Ghiorso 1991 ). Selected chemical analyses of ferritchromite cores from the Kalkan chromitite are shown in diamonds.
Image
Image analysis example showing threshold process results: (a) chromian-chlorite in white, chromite and ferritchromite in black; (b) chromite in white, chromian-chlorite and ferritchromite in black; (c) ferritchromite in white, chromite and chromian-chlorite in black; (d) sum of a, b, and c; chromian-chlorite in gray, chromite in white and ferritchromite in black. Mineral phases were isolated, according to their characteristic range of gray level intensity and each associated area has been calculated.
Published: 01 October 2009
F igure 4. Image analysis example showing threshold process results: ( a ) chromian-chlorite in white, chromite and ferritchromite in black; ( b ) chromite in white, chromian-chlorite and ferritchromite in black; ( c ) ferritchromite in white, chromite and chromian-chlorite in black; ( d ) sum
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Backscattered electron photomicrographs showing the typical textures of the spinels. A) Coarse magnetite I grain associated with partially altered perovskite. B) Magnetite I grain exhibiting hematite exsolutions (hem I; martitization) (transition zone). C) Magnetite I with trellis-type ilmenite exsolutions (ferruginous saprolite). D) Chromite grain with pervasive alteration rim (transition zone). E) Ferritchromite I enclosing amphibole and Ni-Fe(Co) sulfide inclusions (transition zone). F) Ferritchromite II replacing ferritchromite I (ferruginous saprolite). Minerals abbreviations: am = amphibole, chr = chromite, Fe-chr = ferritchromite, hem = hematite, ilm = ilmenite, mt = magnetite, pev = perovskite.
Published: 01 June 2021
ilmenite exsolutions (ferruginous saprolite). D) Chromite grain with pervasive alteration rim (transition zone). E) Ferritchromite I enclosing amphibole and Ni-Fe(Co) sulfide inclusions (transition zone). F) Ferritchromite II replacing ferritchromite I (ferruginous saprolite). Minerals abbreviations: am
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Photomicrographs and Backscattered Electron (BSE) images of different types of oxides: (a), (b) Less fractured type-I chromite showing the development of ferritchromit (R1) and chrome magnetite (R2) rims surrounding the chromite core; (c), (d) Type-II chromite showing dark grey chromite core surrounded by light grey porous and non-porous rims of ferritchromit (R1 and R2 respectively) followed by outermost high reflectance chrome magnetite (R3) rim; (e) Type-III chromite showing amalgamation of small chromite grains with ferritchromit core and chrome magnetite rim; (f) Magnetite in the chrysotile-chlorite vein; dotted yellow circle in (b), (c), (d), (e) represents type-IV grains. Chl: chlorite, Ctl: chrysotile, Mag: magnetite. Mineral names abbreviations are from Whitney and Evans (2010).
Published: 01 March 2023
Fig. 4. Photomicrographs and Backscattered Electron (BSE) images of different types of oxides: (a) , (b) Less fractured type-I chromite showing the development of ferritchromit (R1) and chrome magnetite (R2) rims surrounding the chromite core; (c) , (d) Type-II chromite showing dark grey
Image
Photomicrographs showing petrographic textures under crossed nicols (a, b, c, d, and f) and reflected light (e, g, and h). Abbreviations: Ol = olivine, Cb = carbonates, Spl = spinel, Fu = Fuschite, Srp = serpentine, Qtz = quartz, Mt = magnetite. (a) Fresh relic of olivine within serpentinite; (b) bastite texture after orthopyroxene; (c) antigorite crystals intergrown with magnesite; (d) scattered blocky aggregates of carbonates within serpentinite; (e) large chromian spinel crystal with pristine core followed by an irregular light-gray ferritchromite zone and a gray-white magnetite rim; (f) fuchsite flakes with a perfect cleavage in one direction; (g) chromian spinel in listwaenite overprinted by thin rims of ferritchromite along margins and later cracks; and (h) chromian spinel in Type II listwaenite-like rock highly altered to ferritchromite.
Published: 01 July 2018
of olivine within serpentinite; ( b ) bastite texture after orthopyroxene; ( c ) antigorite crystals intergrown with magnesite; ( d ) scattered blocky aggregates of carbonates within serpentinite; ( e ) large chromian spinel crystal with pristine core followed by an irregular light-gray ferritchromite zone
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Photomicrographs of mafic and ultramafic rocks in the ophiolitic sequence (a, b, and d were taken in cross-polarized transmitted light, while c was taken in plane transmitted light). a, Flaky crystals of antigorite. b, Fresh relicts of olivine within mesh texture. c, Cr-spinel highly altered into ferritchromite. d, Secondary amphibole after pyroxene. Ant = antigorite; Carb = carbonates; Ol = olivine; Plag = plagioclase; Amph = amphibole; Sp = spinel; FrCr = ferritchromite.
Published: 01 March 2023
-spinel highly altered into ferritchromite. d , Secondary amphibole after pyroxene. Ant = antigorite; Carb = carbonates; Ol = olivine; Plag = plagioclase; Amph = amphibole; Sp = spinel; FrCr = ferritchromite.
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Reflected light and backscattered electron photomicrographs for Hili Manu chromitites. (A) Massive chromitite with systematic fracturing. (B) Massive fractured chromitite with brecciated zone. (C) Brecciated chromitite with complete ferritchromit alteration. (D) Brecciated subhedral and angular unaltered chromite grains. (E) Lobate texture with relict fresh olivine and small base-metal sulfide grain (indicated by the arrow) within the matrix. (F) Rim replacement of lobate texture chromite by ferritchromit.
Published: 01 September 2017
Figure 7. Reflected light and backscattered electron photomicrographs for Hili Manu chromitites. (A) Massive chromitite with systematic fracturing. (B) Massive fractured chromitite with brecciated zone. (C) Brecciated chromitite with complete ferritchromit alteration. (D) Brecciated subhedral
Journal Article
Published: 01 March 2023
Jour. Geol. Soc. India (2023) 99 (3): 345–356.
...Fig. 4. Photomicrographs and Backscattered Electron (BSE) images of different types of oxides: (a) , (b) Less fractured type-I chromite showing the development of ferritchromit (R1) and chrome magnetite (R2) rims surrounding the chromite core; (c) , (d) Type-II chromite showing dark grey...
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Journal Article
Published: 01 June 1974
American Mineralogist (1974) 59 (5-6): 608–612.
... percent. Ferritchromite occurs as rims on chromite crystals that are bordered by chlorite and (where still available) olivine. Microprobe analyses of chromite, ferritchromite, chrome-magnetite, olivine, and chlorite show that the chromite-ferritchromite boundary is sharp (less than 10 microns...
Image
A. Sample C63 a2, Pd-Cu antimonide (white) adjacent to a Ni-sulfide, millerite (pale gray), surrounded by ferritchromit with an uneven polish (gray) and altered silicate (black). B. Sample C54 b2, two grains of Cu6Pd (white, analysis C54 b2 Table 3b), the larger one partially surrounded by Cu-Pd oxide (pale gray) associated with altered silicate (dark gray) in chromite (gray) altered on the margins to ferritchromit. C. Sample C311 a2, stringers of native Pt containing traces of Ni (white) in cracks in chromite (gray) partially altered on its edges and along cracks to ferritchromit (paler gray) and in silicate (black). D. Sample C123 e1, cracked and altered Ru-Rh-Ir-Pt-Fe-Mn oxide surrounded by altered silicate and chromite and in close proximity (at a distance of 10 μm) to two grains of barite (BaSO4) not shown. E. Sample C123 a1, composite PGM of Ru-Ir-As-S (1) and Ru-Ir-As-S oxide (2, analysis C123 a1,2 and Table 3c) surrounded by chromite (gray) veined by altered silicate (dark gray). The grain may be a pseudomorph, as the mottled PGM fill a grain with a subeuhedral outline. F. Sample C63 c1, grain of Ni arsenide (gray) with inclusions of Os-Ir (white) and dark gray lines of Ni-Pt oxide enclosed in altered silicate and adjacent to a small grain of Pt-Pd-Ni-Cu alloy (right, pale gray) G. Sample C54 c2, Cu6(Pd,Pt) (1, white, analysis C54 c2,1 in Table 3b) altering to a Cu-Pd-Pt oxide (2 pale gray, analysis C54 c2,2 in Table 3c) adjacent to mottled Cu-Pd oxide (gray) on the edge of a chromite (darker gray) altering on the edges to ferritchromit (paler gray) and partially surrounded by chlorite (black). White dots are Ru-Ir alloys (Ru). H. Sample C63 a1, Pt oxide (Ox, pale gray) with Pt-Pd-Ni oxide (Pt) and Pd-Pt-Ni oxide (Pd) adjacent to silicate (black) and ferritchromit (gray) with cores of chromite (darker gray).
Published: 01 November 2008
F ig . 8. A. Sample C63 a2, Pd-Cu antimonide (white) adjacent to a Ni-sulfide, millerite (pale gray), surrounded by ferritchromit with an uneven polish (gray) and altered silicate (black). B. Sample C54 b2, two grains of Cu 6 Pd (white, analysis C54 b2 Table 3b ), the larger one partially
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Compositional variations of four major oxides (Cr2O3, MgO, Al2O3 and FeOt) along line A-A’ (as shown in Fig. 5) within a spinel porphyroclast. (a) MgO and Cr2O3 content (wt%) highest in innermost relict spinel grains and fall gradually along the traverse from ferritchromit to magnetite. (b) Al2O3 content (wt%) is highest in relict spinel, and variable in ferritchromit, while FeOt content (wt%) is lowest in relict spinel but highest within the magnetite.
Published: 01 July 2015
ferritchromit to magnetite. (b) Al 2 O 3 content (wt%) is highest in relict spinel, and variable in ferritchromit, while FeO t content (wt%) is lowest in relict spinel but highest within the magnetite.
Journal Article
Published: 01 September 1996
Jour. Geol. Soc. India (1996) 48 (3): 265–276.
...J. K. Mohanty; R. K. Sahoo; A. K. Paul Abstract During Serpentinization of the ultramafic rocks, the accessory chrome spinels are altered at grain margins and/or along fractures to highly reflecting phases of ferritchromit and magnetite which occur as rims around parent chromite. Of these two...
Journal Article
Published: 01 February 1993
American Mineralogist (1993) 78 (1-2): 68–74.
... chromite, formerly called “ferritchromit.” The chlorite is a Cr-bearing IIb clinochlore, and the inclusions occur preferentially within “ferritchromit.” The orientation relationship is c chlorile * ||[111] chromite , a chlorite ||[ h h 0] chromite , and b chlorite ||[ hh 2 h ] chromite . This is equivalent...
Journal Article
Published: 01 April 1989
American Mineralogist (1989) 74 (3-4): 448–455.
...Marek A. Zakrzewski Abstract Chromian spinels have been observed as disseminated accessoriesin gabbroic rocks and ores from the abandoned Ni‐Cu mine of Kuså, in the Proterozoic metallogenic province of Bergslagen, Sweden. They occur as unzoned grains of “ferritchromit” ( Fe 0.9 2 + Mg 0.1 Fe 1.2 3...