Results 191 to 200 of about 90,092 (222)
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Phosphorus zoning reveals dendritic architecture of olivine
Geology, 2014Quantitative spot analyses were acquired with the JEOL JXA-8500F field-emission gun electron probe micro-analyzer of the University of Hawaii – Manoa over two sessions. Olivine was analyzed during the first session with an electron beam tuned at 20 keV, 50 nA and 10 µm probe diameter. The elements were acquired using five analyzing crystals as followed:
Benoit Welsch +2 more
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The origin of ferrous zoning in Allende chondrule olivines
Geochimica et Cosmochimica Acta, 1987Abstract Olivine crystals in Allende Type 1 chondrules have ferrous rims (Fa15–44), a few microns thick, at grain surfaces and along crosscutting cracks. This ferrous olivine contains as much as 2 atomic pet. Al and Cr and 0.2 pct. Ti. Along cracks, profiles of Fe, Al, Cr and Ti are consistent with difrusional emplacement: these elements moved from ...
Julia A Peck, John A Wood
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Zoned olivines in four Apollo 12 samples
Earth and Planetary Science Letters, 1971Abstract The distributions of Fe, Mg, Si, Ca, Mn, and Cr in selected olivine crystals from 12040, 12052, 12075 and 12076 have been determined by electron probe analysis. The results indicate that all crystals are continuously zoned, almost certainly as a result of fractional crystallization.
F.G.F. Gibb, J. Zussman
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Zoned olivines and their petrogenetic significance
Mineralogical Magazine and Journal of the Mineralogical Society, 1939The object of this paper is to demonstrate the widespread occurrence of zoned olivines in igneous rocks, to show that the zoning is continuous, that the composition varies from a magnesium-rich centre to an iron-enriched margin, and that these findings have an important bearing on the question of petrogenesis.I propose to express the composition of ...
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Melting Products of Olivine Tholeiite Basalt in Subduction Zones
Geology, 1974Microprobe analysis of the near liquidus minerals in the crystallization interval of basalt +5 percent H2O and andesite +5 percent H2O at 30 kb, combined with similar published data from other studies of hydrous and anhydrous calc-alkaline rock compositions, defines compositional trends that permit calculation of the compositions of minerals through ...
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Contributions to Mineralogy and Petrology, 1979
Olivine melilitites from Namaqualand, South Africa are characterized by a broad range in olivine compositions on the scale of individual hand specimens. It is possible to distinguish four petrographically and chemically distinct olivine populations in both the northern and southern pipe clusters studied: (a) Scarce anhedral or subhedral olivines that ...
Erlank, A. J., Moore, A. E.
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Olivine melilitites from Namaqualand, South Africa are characterized by a broad range in olivine compositions on the scale of individual hand specimens. It is possible to distinguish four petrographically and chemically distinct olivine populations in both the northern and southern pipe clusters studied: (a) Scarce anhedral or subhedral olivines that ...
Erlank, A. J., Moore, A. E.
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Earth and Planetary Science Letters, 2013
Abstract The Fizh massif, Oman Ophiolite, contains a ductile shear zone at the Moho Transition Zone. The dunites in the shear zone are classified based on microstructures into coarse granular texture, medium-grained texture, mylonite, and ultramylonites toward a gabbro contact.
Katsuyoshi Michibayashi, Tatsuya Oohara
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Abstract The Fizh massif, Oman Ophiolite, contains a ductile shear zone at the Moho Transition Zone. The dunites in the shear zone are classified based on microstructures into coarse granular texture, medium-grained texture, mylonite, and ultramylonites toward a gabbro contact.
Katsuyoshi Michibayashi, Tatsuya Oohara
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Earth and Planetary Science Letters, 2016
Abstract In regions of the mantle where multi-phases coexist like at the olivine–wadsleyite–ringwoodite transitions, the stress induced by the seismic waves may drive a mineralogical reaction between the low to high pressure phases, a possible source of dissipation.
Perrillat, Jean-Philippe +6 more
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Abstract In regions of the mantle where multi-phases coexist like at the olivine–wadsleyite–ringwoodite transitions, the stress induced by the seismic waves may drive a mineralogical reaction between the low to high pressure phases, a possible source of dissipation.
Perrillat, Jean-Philippe +6 more
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The theory of zoning patterns in magmatic minerals using olivine as an example
Contributions to Mineralogy and Petrology, 1987A theory of simple zoned growth in magmatic minerals is developed using olivine as an example. The law of growth in absolute FeO-MgO space has the form (Y0-Ys) = A*(X0-Xs)k* where X refers to FeO, Y refers to MgO and the subscript s refers to the solid phase.
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Floating-zone growth of single-crystal olivine [(Mg1-xFex)2SiO4]
Journal of Crystal Growth, 1982Abstract Large single crystals of olivine [(Mg 1-x Fe x ) 2 SiO 4 ] were grown over an incremental range of x between 0 and 1.0 under a controlled oxygen fugacity using a lamp-image, floating zone furnace. The transparent rod-shaped crystals have maximum sizes 70 mm in length by 7 mm in diameter.
Syoichi Hosoya, Humihiko Takei
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