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![Geology of the lower gabbroic rocks of the Liuyuan Complex. (A) Medium-grained troctolite, showing a typical poikilitic texture, with centimeter-scale clinopyroxene oikocrysts and predominantly olivine chadacrysts. (B) Troctolite in thin section. Note the alignment of euhedral plagioclase grains, defining a weak but noticeable magmatic foliation. Dihedral angles between plagioclase grains are approximately 60°, indicating some amount of solidus reequilibration has occurred. (C) Medium-grained melatroctolite. (D) Clinopyroxene oikocryst (second-order blue interference color) and euhedral olivine chadacrysts in melatroctolite. (E) Layered intrusion in the Liuyuan Complex. The composition of individual layers ranges from melatroctolite to anorthosite, and layer thickness ranges between 0.5 and 5 cm. (F) Medium-grained subophitic gabbro; part of the varitextured olivine gabbro overlying the lower troctolite cumulates in the Liuyuan Complex. (G) Olivine gabbro in thin section, showing ~20% interstitial clinopyroxene. (H) Gabbroic pegmatite showing mingled texture with an intruding plagiogranite. Clinopyroxene reaches up to 7 cm in length. Hammer is ~35 cm in length, and the coin diameter is 2.65 cm. Ol—olivine; Pl—plagioclase; Cpx—clinopyroxene.]()
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![First thumbnail for: Re-Os Isotope Systematics of the Voisey’s Bay Ni-C...]()
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![Textures of Waterberg troctolite and its relationships with other rocks. (A) Irregular troctolite lenses among coarse-grained to pegmatoidal poikilitic harzburgite. (B) Orthopyroxene oikocryst in troctolite. (C) Mela- and leucotroctolite network between fragments of poikilitic harzburgite. (D) Sharp contact between pegmatoidal harzburgite and coarse-grained melatroctolite. (E) Poikilitic pigeonite oikocryst in troctolite. (F) Harrisitic olivine in altered melatroctolite of the F mineralized zone. (G) Contact of olivine-rich feldspathic harzburgite and pyroxenite in the T mineralized zone, the base of the Upper zone. (H) Leucotroctolite veining in melagabbronorite of the troctolite-gabbronorite-anorthosite sequence. Abbreviations: Cpx = clinopyroxene, Ol = olivine, Opx = orthopyroxene, Phl = phlogopite, Pl = plagioclase, Sfd = sulfide. Half NQ core; sample numbers in the bottom left corners.]()
![Long section of the Eagle and East Eagle intrusions showing the relationship at depth between the two deposits, along with the ramp that will connect the two once the East Eagle deposit is actively mined. Contact with the Archean basement rock is depicted. Black bars along drill holes, with arrows pointing toward them, indicate approximate (due to high drill core density) sample locations. Every core sampled includes at least one, and usually more, individual samples from the disseminated sulfide. Disseminated sulfides occur in all of the gabbroic to melatroctolitic rocks (shown in purple). The region within the outlined shape, labeled “Melatroctolite, Ding et al., 2012b,” indicates the known extent of the East Eagle intrusion at that time. Figure courtesy of Lundin Mining.]()
![Fig. 5.]()
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![Forsterite contents of olivine from the main gabbro and the pocket peridotite unit compared to Fo contents of olivine from the melatroctolite at Eagle East (Hinks, 2016)]()
![Plagioclase compositions for the main gabbro unit, pyroxenite rim, and pocket peridotite compared with compositions of the melatroctolite unit at Eagle East (Ding et al., 2010).]()
![Representative thin section scans and photomicrographs from FD-13–34. (A) The Layered Series olivine gabbro with typical equigranular and intergranular texture. (B) The Layered Series oxide augite melatroctolite showing abundant magnetite (25% modal) interstitial to Ol, Cpx, and Plag. (C) The coarse-grained oxide melatroctolite of the Marathon Series within the Marker Horizon, which is relatively enriched in Plag. (D) The apatitic clinopyroxenite of the Marathon Series shows Cpx cumulates with interstitial Plag and Mt. (E) Cross-polarized transmitted light photomicrograph showing early Plag rimmed by late Plag intergrown with Ccp. (F) Reflected-light photomicrograph showing Ccp; some Ccp grains are rimmed by hydrothermal Mt. Abbreviations: Ol, olivine; Cpx, clinopyroxene; Plag, plagioclase; Mt, magnetite; Chl, chlorite; Bio, biotite; Ap, apatite; Act, actinolite; Ccp, chalcopyrite; Po, pyrrhotite.]()
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1-20 OF 82 RESULTS FOR
melatroctolite
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1
Journal Article
Melatroctolite–anorthositic gabbro complex, Cumberland, Rhode Island: Petrology, origin, and regional setting Available to Purchase
Journal: GSA Bulletin
Publisher: Geological Society of America
Published: 01 July 1984
GSA Bulletin (1984) 95 (7): 844–854.
... is not well constrained but appears to be between 620 and 370 m.y. B.P. The mafic complex in northern Rhode Island consists of a small body of melatroctolite adjacent to a much larger body (1 km 2 ) of anorthositic gabbro. The contact between the two rock types is not exposed, but inclusions of anorthositic...
Journal Article
Contrasting Petrological and Geochemical Relationships in the Voisey’s Bay and Mushuau Intrusions, Labrador, Canada: Implications for Ore Genesis Available to Purchase
Journal: Economic Geology
Publisher: Society of Economic Geologists
Published: 01 June 2000
Economic Geology (2000) 95 (4): 771–799.
... that has been intruded by a stellate-textured troctolite along its contact with footwall orthogneiss. The layered unit consists dominantly of melatroctolite at the margin with leucotroctolite toward the center and olivine gabbro at the core. The cumulates of the Mushuau intrusion are richer in olivine...
FIGURES
Image
Geology of the lower gabbroic rocks of the Liuyuan Complex. (A) Medium-grai... Available to Purchase
in Geology of the Liuyuan Complex, NW China: A Permian back-arc basin ophiolite at the southern edge of the Central Asian orogenic belt
> GSA Bulletin
Published: 09 February 2023
plagioclase grains, defining a weak but noticeable magmatic foliation. Dihedral angles between plagioclase grains are approximately 60°, indicating some amount of solidus reequilibration has occurred. (C) Medium-grained melatroctolite. (D) Clinopyroxene oikocryst (second-order blue interference color
Journal Article
The role of magma injection and crystal sorting in the formation of early gabbros at the Coldwell Complex, Ontario, Canada Available to Purchase
Journal: Canadian Journal of Earth Sciences
Publisher: Canadian Science Publishing
Published: 13 February 2019
Canadian Journal of Earth Sciences (2019) 56 (7): 715–737.
... of thick accumulations of olivine gabbro and oxide augite melatroctolite. This study combines petrography, mineral chemistry, and lithogeochemistry to constrain the magma composition and petrogenesis of the Layered Series. The presence of cumulus orthoclase together with the observation that the Layered...
FIGURES
Journal Article
Re-Os Isotope Systematics of the Voisey’s Bay Ni-Cu-Co Magmatic Sulfide System, Labrador, Canada: II. Implications for Parental Magma Chemistry, Ore Genesis, and Metal Redistribution Available to Purchase
Journal: Economic Geology
Publisher: Society of Economic Geologists
Published: 01 June 2000
Economic Geology (2000) 95 (4): 867–888.
... isotope data for unmineralized melatroctolite inclusions within the Basal Breccia sequence. These inclusions contain olivine with high MgO and Ni concentrations and low La/Sm and Th/Nb ratios, a high Os concentration, and an enriched (but near-chondritic) initial Os isotope composition ( λ Os = 9...
FIGURES
Journal Article
The application of portable XRF and benchtop SEM-EDS to Cu-Pd exploration in the Coldwell Alkaline Complex, Ontario, Canada Available to Purchase
Publisher: Geological Society of London
Published: 09 August 2016
Geochemistry: Exploration, Environment, Analysis (2016) 16 (3-4): 193–212.
...: Comparisons of pXRF analyses with ICP-AES, ICP-MS and IR analysis are available at http://doi.org/10.6084/m9.figshare.c.3291518 A 70 m thick sequence of oxide-rich units consisting of, from top to bottom, oxide augite melatroctolite and oxide melatroctolite, which separates the Layered Series from...
FIGURES
Image
Textures of Waterberg troctolite and its relationships with other rocks. (A... Available to Purchase
in Formation of Spinel-Orthopyroxene Symplectites by Reactive Melt Flow: Examples from the Northern Bushveld Complex and Implications for Mineralization in Layered Intrusions
> Economic Geology
Published: 01 December 2022
. (D) Sharp contact between pegmatoidal harzburgite and coarse-grained melatroctolite. (E) Poikilitic pigeonite oikocryst in troctolite. (F) Harrisitic olivine in altered melatroctolite of the F mineralized zone. (G) Contact of olivine-rich feldspathic harzburgite and pyroxenite in the T mineralized
Image
Long section of the Eagle and East Eagle intrusions showing the relationshi... Available to Purchase
in Multiple S Isotopes and S Isotope Heterogeneity at the East Eagle Ni-Cu-Platinum Group Element Deposit, Northern Michigan
> Economic Geology
Published: 01 May 2020
, with arrows pointing toward them, indicate approximate (due to high drill core density) sample locations. Every core sampled includes at least one, and usually more, individual samples from the disseminated sulfide. Disseminated sulfides occur in all of the gabbroic to melatroctolitic rocks (shown in purple
Image
Down-hole mineral chemical and lithogeochemical profiles in drill hole FD-1... Available to Purchase
in The role of magma injection and crystal sorting in the formation of early gabbros at the Coldwell Complex, Ontario, Canada
> Canadian Journal of Earth Sciences
Published: 13 February 2019
and oxide augite melatroctolite. Ol, olivine; Cpx, clinopyroxene; Pl, plagioclase; OG, olivine gabbro; OAM, oxide augite melatroctolite. [Color online.]
Image
F IG 11. Photographs and photomicrographs showing textural and mineralogic... Available to Purchase
in Contrasting Petrological and Geochemical Relationships in the
Voisey’s Bay and Mushuau Intrusions, Labrador, Canada: Implications for Ore
Genesis
> Economic Geology
Published: 01 June 2000
F IG 11. Photographs and photomicrographs showing textural
and mineralogical relationships in the Mushuau intrusion rocks. Crn = corundum,
Hcn = hercynite, Ol = olivine, Pl = plagioclase. Width of view is 4 mm. A. An
outcrop photo showing modal layering in the melatroctolite unit. B. Microscopic
Image
Forsterite contents of olivine from the main gabbro and the pocket peridoti... Available to Purchase
in Episodic Nature of Magmatic Ascent in a Dynamic Conduit System: Evidence From a Late Gabbroic Intrusion Associated with the Eagle Ni-Cu Sulfide Deposit in Northern Michigan, USA
> Economic Geology
Published: 01 August 2022
Fig. 10. Forsterite contents of olivine from the main gabbro and the pocket peridotite unit compared to Fo contents of olivine from the melatroctolite at Eagle East ( Hinks, 2016 )
Image
Plagioclase compositions for the main gabbro unit, pyroxenite rim, and pock... Available to Purchase
in Episodic Nature of Magmatic Ascent in a Dynamic Conduit System: Evidence From a Late Gabbroic Intrusion Associated with the Eagle Ni-Cu Sulfide Deposit in Northern Michigan, USA
> Economic Geology
Published: 01 August 2022
Fig. 11. Plagioclase compositions for the main gabbro unit, pyroxenite rim, and pocket peridotite compared with compositions of the melatroctolite unit at Eagle East ( Ding et al., 2010 ).
Image
Representative thin section scans and photomicrographs from FD-13–34. ( A )... Available to Purchase
in The application of portable XRF and benchtop SEM-EDS to Cu-Pd exploration in the Coldwell Alkaline Complex, Ontario, Canada
> Geochemistry: Exploration, Environment, Analysis
Published: 09 August 2016
Fig. 3. Representative thin section scans and photomicrographs from FD-13–34. ( A ) The Layered Series olivine gabbro with typical equigranular and intergranular texture. ( B ) The Layered Series oxide augite melatroctolite showing abundant magnetite (25% modal) interstitial to Ol, Cpx, and Plag
Image
Major element concentrations for the Layered Series intersected by two repr... Available to Purchase
in The role of magma injection and crystal sorting in the formation of early gabbros at the Coldwell Complex, Ontario, Canada
> Canadian Journal of Earth Sciences
Published: 13 February 2019
Table 2. Major element concentrations for the Layered Series intersected by two representative drill holes on Area 41 (SL-13-34) and Four Dams (FD-13-34). Note: OG, olivine gabbro; OAM, oxide augite melatroctolite.
Image
Trace element concentrations for the Layered Series intersected by two repr... Available to Purchase
in The role of magma injection and crystal sorting in the formation of early gabbros at the Coldwell Complex, Ontario, Canada
> Canadian Journal of Earth Sciences
Published: 13 February 2019
Table 3. Trace element concentrations for the Layered Series intersected by two representative drill holes on Area 41 (SL-13-34) and Four Dams (FD-13-34). Note: OG, olivine gabbro; OAM, oxide augite melatroctolite.
Journal Article
Geology of the Liuyuan Complex, NW China: A Permian back-arc basin ophiolite at the southern edge of the Central Asian orogenic belt Available to Purchase
Journal: GSA Bulletin
Publisher: Geological Society of America
Published: 09 February 2023
GSA Bulletin (2023) 135 (11-12): 2830–2848.
... plagioclase grains, defining a weak but noticeable magmatic foliation. Dihedral angles between plagioclase grains are approximately 60°, indicating some amount of solidus reequilibration has occurred. (C) Medium-grained melatroctolite. (D) Clinopyroxene oikocryst (second-order blue interference color...
FIGURES
Journal Article
Evolution of the Main Zone at the Marathon Cu-PGE Sulfide Deposit, Midcontinent Rift, Canada: Spatial Relationships in a Magma Conduit Setting Available to Purchase
Journal: Economic Geology
Publisher: Society of Economic Geologists
Published: 01 June 2015
Economic Geology (2015) 110 (4): 983–1008.
... but includes a layered troctolite sill and numerous small oxide melatroctolite to apatitic olivine clinopyroxenite sill-like to pod-shaped bodies that crosscut the Fine-Grained Series. The relative distribution of these units is displayed in Figures 3 and 4 . A magma conduit model has been...
FIGURES
Image
Summary of the Mg# of olivine and clinopyroxene, the anorthite content of p... Available to Purchase
in The role of magma injection and crystal sorting in the formation of early gabbros at the Coldwell Complex, Ontario, Canada
> Canadian Journal of Earth Sciences
Published: 13 February 2019
Table 5. Summary of the Mg# of olivine and clinopyroxene, the anorthite content of plagioclase, and whole-rock Rb, Sr, Ba, Zr, La/Sm, and Gd/Yb for subunits identified in drill holes FD-13-34 and SL-13-34. Note: OG, olivine gabbro; OAM, oxide augite melatroctolite; Ol, olivine; Cpx
Journal Article
Raman spectroscopy of titanomagnetites: Calibration of the intensity of Raman peaks as a sensitive indicator for their Ti content Available to Purchase
Journal: American Mineralogist
Publisher: Mineralogical Society of America
Published: 01 October 2011
American Mineralogist (2011) 96 (10): 1537–1546.
... and nearly disappears at x = ~0.6. Combining the two relative intensities potentially provides a sensitive indicator of Ti content. The technique was applied to study titanomagnetite in grains from Hana Volcanics and melatroctolite from Rhode Island. Titanomagnetites Raman spectroscopy Fe-Ti oxides...
FIGURES
Image
Outcrop, thin section scans, and photomicrographs of the Layered Series uni... Available to Purchase
in The role of magma injection and crystal sorting in the formation of early gabbros at the Coldwell Complex, Ontario, Canada
> Canadian Journal of Earth Sciences
Published: 13 February 2019
melatroctolite at Area 41 shows intergranular Ol, Cpx, and Pl. ( h ) The oxide augite melatroctolite at Four Dams, cross-polar transmitted light photomicrograph, shows deformed twinning of Pl. Ol, olivine; Cpx, clinopyroxene; Pl, plagioclase; Mt, Magnetite; Ap, apatite; Bt, biotite. [Color online.]
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