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spinel

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Journal Article
Journal: Clay Minerals
Published: 01 September 2018
Clay Minerals (2018) 53 (3): 305-324.
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Series: Geological Society, London, Special Publications
Published: 01 January 2018
DOI: 10.1144/SP463.6
EISBN: 9781786203441
...; ( c ) Parallel to sub-parallel exsolved spinel grains (domain highlighted by dotted white ellipse) in the phlogopite; note the inclusions of apatite in the phlogopite and clinopyroxene, as well as in the serpentinized olivine. Irregular patches of pyrite are also present. Abbreviations: Ol, olivine...
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Journal Article
Journal: Lithosphere
Published: 14 July 2017
Lithosphere (2017) 10 (1): 54-78.
... chromitite deposits. We present new whole-rock major element, trace element, rare earth element (REE), and platinum group element chemistry to evaluate their mantle melt evolution and petrogenesis. Harzburgites have high average CaO, Al 2 O 3 , and REE contents, and contain Al-rich pyroxene and spinel...
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Journal Article
Journal: Geology
Published: 10 July 2017
Geology (2017) 45 (9): 807-810.
... of pelagic Maiolica limestone of Berriasian–Hauterivian age from Italy, we recovered 108 extraterrestrial spinel grains (32–250 μm) representing relict minerals from coarse micrometeorites. Elemental and three oxygen isotope analyses were used to characterize the grains, providing a first-order estimate...
FIGURES
Journal Article
Journal: Lithosphere
Published: 18 May 2017
Lithosphere (2017) 10 (1): 79-94.
...# = 89.6–91.9), clinopyroxene (En 46–49 Wo 47–50 Fs 3–5 ; Mg# = 90.9–93.6), and spinel (Mg# = 67.1–78.9; Cr# = 13.5–31.5), and have relatively homogeneous whole-rock compositions with Mg#s of 90.1–90.8 and SiO 2 (41.5–43.65 wt%), Al 2 O 3 (1.66–2.66 wt%), and CaO (1.45–2.67 wt%) contents. They display...
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... the reconstruction of the thermal-tectonic evolution of the lithospheric mantle. The exsolution of orthopyroxene and garnet and rare spinel, plagioclase, and ilmenite from complex clinopyroxene megacrysts suggests that the xenoliths originally were clinopyroxene-dominant cumulates associated with minor garnet...
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Series: GSA Special Papers
Published: 01 May 2015
DOI: 10.1130/2015.2511(12)
... High-Mg Kroenke-type basalts containing 9–11 wt% MgO from the Ontong Java Plateau (OJP) include spinels. These spinels have nearly identical Cr/(Cr + Al) ratios (0.45–0.54), and are generally hosted by olivine phenocrysts with relatively primitive compositions, with Fo contents [100 × Mg/(Mg...
Journal Article
Published: 01 November 2001
American Mineralogist (2001) 86 (11-12): 1435-1446.
...Eric Reusser; Reto Gieré; Gregory R. Lumpkin Abstract Euhedral crystals of purple spinel are associated with calcite and forsterite in the central zone of composite metasomatic veins of the Adamello contact aureole (Northern Italy). In thin section, spinel is generally colorless, but exhibits...
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Journal Article
Published: 01 April 2001
The Canadian Mineralogist (2001) 39 (2): 361-376.
...Daniel J. Schulze Abstract A comparison is made of the major- and minor-element compositions of spinel-group minerals that occur as single-crystal macrocrysts in kimberlites from southern Africa (approximately 1500 grains from 20 kimberlites on the Kaapvaal and Zimbabwe cratons) with those from...
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Journal Article
Journal: Economic Geology
Published: 01 December 2000
Economic Geology (2000) 95 (8): 1701-1717.
...Stephen J. Barnes; V. Y. Kunilov Abstract Spinels from the mineralized Noril’sk 1 and Talnakh intrusions show a broad and distinctive compositional spectrum, from normal chromite to Ti-enriched aluminous magnetite. In the Talnakh intrusion, in particular, the range of spinel compositions extends...
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Journal Article
Published: 01 October 2000
Mineralogical Magazine (2000) 64 (5): 779-790.
... was intruded concordantly by a magmatic mush of liquid and olivine phenocrysts ( mg ≥83) to form a picrite sill with a D-shaped modal olivine profile. Also present in the picrite magma were discrete spinel micro-phenocrysts with mg ≥12 and cr+al [= mol.% (chromite + spinel)/(chromite + spinel + ulvospinel...
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Journal Article
Published: 01 October 2000
American Mineralogist (2000) 85 (10): 1397-1405.
...Erik Wulff-Pedersen; Else-Ragnhild Neumann; Ernst A.J. Burke; Riccardo Vannucci; Piero Bottazzi; Luisa Ottolini; Jon Gjønnes; Vidar Hansen Abstract Two spinel dunite xenoliths (Fo 89.8–91.2 in olivine) from La Palma contain minor amounts (<1%) of a pale-blue sodalite-group mineral with haüyne...
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Journal Article
Published: 01 August 2000
The Canadian Mineralogist (2000) 38 (4): 975-994.
... are discrete crystals set in a serpentine–calcite mesostasis, and reaction-induced rims on earlier-crystallized oxide minerals (typically ferroan geikielite or magnesian ilmenite). Perovskite precipitates later than macrocrystal spinel (aluminous magnesian chromite), and nearly simultaneously with “reaction...
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Journal Article
Published: 01 May 2000
American Mineralogist (2000) 85 (5-6): 694-697.
... et al. 1995 ). These thiospinels have a spinel-type structure (space group Fd 3 m ), and display considerable mutual solid-solution. Our aims in the present paper are to characterize compositional variations in PGE-rich thiospinels from the Kirakkajuppura PGE deposit of the Penikat layered...
FIGURES
Journal Article
Published: 01 April 1999
The Canadian Mineralogist (1999) 37 (2): 277-296.
Journal Article
Published: 01 April 1999
Mineralogical Magazine (1999) 63 (2): 257-262.
...F. Princivalle; A. Della Giusta; A. De Min; E. M. Piccirillo Abstract Two Mg-Al spinels (FAS1 and FAS2) in high-grade hornfels from the Toal de Mason skarn (Predazzo Monzoni, NE Italy) were investigated by means of single crystal X-ray diffraction and electron microprobe analysis in order...
Journal Article
Journal: Geology
Published: 01 December 1998
Geology (1998) 26 (12): 1111-1114.
.... In the Northampton Block, Western Australia, spinel formed by high-temperature (∼850 °C) partial melting of metapelites is separated from leucosome by garnet ± sillimanite or cordierite ± sillimanite coronas. Formation of the coronas by back reaction with a silica-undersaturated melt is inferred because: (1...
Journal Article
Published: 01 June 1998
The Canadian Mineralogist (1998) 36 (3): 701-711.
Journal Article
Published: 01 June 1998
European Journal of Mineralogy (1998) 10 (3): 521-533.
Journal Article
Journal: Geology
Published: 01 April 1998
Geology (1998) 26 (4): 307-310.
... concentrations. We report here the discovery, in the global stratotype of the Eocene-Oligocene boundary at Massignano in Italy, of Ni-rich spinel, a mineral that forms by the interaction of meteoritic bodies with the Earth's atmosphere. A maximum concentration of ≈800 crystals mg −1 , corresponding to a flux...