Various combinations of diamond, moissanite, zircon, corundum, rutile and titanitehave been recovered from the Bulqiza chromitites. More than 10 grains of diamond have been recovered, most of which are pale yellow to ...Various combinations of diamond, moissanite, zircon, corundum, rutile and titanitehave been recovered from the Bulqiza chromitites. More than 10 grains of diamond have been recovered, most of which are pale yellow to reddish–orange to colorless. The grains are all 100–300 μm in size and mostly anhedral, but with a range of morphologies including elongated, octahedral and subhedral varieties. Their identification was confirmed by a characteristic shift in the Raman spectra between 1325 cm-1 and 1333 cm-1, mostly at 1331.51 cm-1 or 1326.96 cm-1. This investigation extends the occurrence of diamond and moissanite to the Bulqiza chromitites in the Eastern Mirdita Ophiolite. Integration of the mineralogical, petrological and geochemical data of the Bulqiza chromitites suggests their multi–stage formation. Magnesiochromite grains and perhaps small bodies of chromitite formed at various depths in the upper mantle, and encapsulated the ultra–high pressure, highly reduced and crustal minerals. Some oceanic crustal slabs containing the magnesiochromite and their inclusion were later trapped in suprasubduction zones, where they were modified by tholeiitic and boninitic arc magmas, thus changing the magnesiochromite compositions and depositing chromitite ores in melt channels.展开更多
The ultramafic massif of Bulqiza, which belongs to the eastem ophiolitic belt of Albania, is a major source of metallurgical chromitite ore. The massif consists of a thick （〉4 km） sequence, composed from the base u...The ultramafic massif of Bulqiza, which belongs to the eastem ophiolitic belt of Albania, is a major source of metallurgical chromitite ore. The massif consists of a thick （〉4 km） sequence, composed from the base upward of tectonized harzburgite with minor dunite, a transitional zone of dunite, and a magmatic sequence of wehrlite,展开更多
Peridotites are an important part of ophiolites： they not only record plate tectonic settings and events, but also offer help to interpret the composition of the mantle and the effect of the deep mantle. The Yarlung-...Peridotites are an important part of ophiolites： they not only record plate tectonic settings and events, but also offer help to interpret the composition of the mantle and the effect of the deep mantle. The Yarlung-Zangbo suture zone extends more than 2000 km along southern Tibet,展开更多
The Purang ophiolite is a large mantle peridotite massif ca. 600 km2 in area. The mantle peridotite is composed dominantly of harzburgite, lherzolite and minor dunite. The Fo and NiO contents of olivine in the peridot...The Purang ophiolite is a large mantle peridotite massif ca. 600 km2 in area. The mantle peridotite is composed dominantly of harzburgite, lherzolite and minor dunite. The Fo and NiO contents of olivine in the peridotites are in the range of 89.5-92.8 and 0.23-0.44 wt.%,展开更多
Diopside and magnetite exsolutions occur as oriented intergrowths within olivine of the lower Cr# dunite in the Dongbo ophiolite, Tibet. The fresh lower Cr# dunite has a mineral assemblage of olivine, spinel and diops...Diopside and magnetite exsolutions occur as oriented intergrowths within olivine of the lower Cr# dunite in the Dongbo ophiolite, Tibet. The fresh lower Cr# dunite has a mineral assemblage of olivine, spinel and diopside.展开更多
The ultramafic massif of Bulqiza, which belongs to the eastern ophiolitic belt of Albania, is the most important area for metallurgical chromitite ores. The massif consists of a thick （〉4 km） rock sequence, with a ...The ultramafic massif of Bulqiza, which belongs to the eastern ophiolitic belt of Albania, is the most important area for metallurgical chromitite ores. The massif consists of a thick （〉4 km） rock sequence, with a generalized profile from the bottom to the top as follows. The tectonite sequence composed mainly of harzburgites with subordinate intercalations of dunites,展开更多
基金funded by grants from the NSF China(Nos.41502062,41672046,41541017,41641015)the China Geological Survey(Nos.DD20160023-01,201511022)+2 种基金National Key Research and Development Project of China(2016YFC0600310)from the Institute of Geology,Chinese Academy of Geological Sciences(J1526)IGCP–649
文摘Various combinations of diamond, moissanite, zircon, corundum, rutile and titanitehave been recovered from the Bulqiza chromitites. More than 10 grains of diamond have been recovered, most of which are pale yellow to reddish–orange to colorless. The grains are all 100–300 μm in size and mostly anhedral, but with a range of morphologies including elongated, octahedral and subhedral varieties. Their identification was confirmed by a characteristic shift in the Raman spectra between 1325 cm-1 and 1333 cm-1, mostly at 1331.51 cm-1 or 1326.96 cm-1. This investigation extends the occurrence of diamond and moissanite to the Bulqiza chromitites in the Eastern Mirdita Ophiolite. Integration of the mineralogical, petrological and geochemical data of the Bulqiza chromitites suggests their multi–stage formation. Magnesiochromite grains and perhaps small bodies of chromitite formed at various depths in the upper mantle, and encapsulated the ultra–high pressure, highly reduced and crustal minerals. Some oceanic crustal slabs containing the magnesiochromite and their inclusion were later trapped in suprasubduction zones, where they were modified by tholeiitic and boninitic arc magmas, thus changing the magnesiochromite compositions and depositing chromitite ores in melt channels.
文摘The ultramafic massif of Bulqiza, which belongs to the eastem ophiolitic belt of Albania, is a major source of metallurgical chromitite ore. The massif consists of a thick （〉4 km） sequence, composed from the base upward of tectonized harzburgite with minor dunite, a transitional zone of dunite, and a magmatic sequence of wehrlite,
基金supported by grants from the Ministry of Science and Technology of China (2014DFR21270)China Geological Survey (12120115026801, 12120115027201, 201511022)the Fund from the State Key Laboratory of Continental Tectonics and Dynamics (Z1301-a20)
文摘Peridotites are an important part of ophiolites： they not only record plate tectonic settings and events, but also offer help to interpret the composition of the mantle and the effect of the deep mantle. The Yarlung-Zangbo suture zone extends more than 2000 km along southern Tibet,
文摘The Purang ophiolite is a large mantle peridotite massif ca. 600 km2 in area. The mantle peridotite is composed dominantly of harzburgite, lherzolite and minor dunite. The Fo and NiO contents of olivine in the peridotites are in the range of 89.5-92.8 and 0.23-0.44 wt.%,
基金funded by grants from Sinoprobe-05-02 from the Ministry of Science and Technology of Chinathe NSF China (Nos. 40930313, 40921001, 41202036)+1 种基金the China Geological Survey (Nos. 1212011121263, 12120114061801, 2014DFR2127C)project from Institute of Geology, Chinese Academy of Geological Sciences (J1526)
文摘Diopside and magnetite exsolutions occur as oriented intergrowths within olivine of the lower Cr# dunite in the Dongbo ophiolite, Tibet. The fresh lower Cr# dunite has a mineral assemblage of olivine, spinel and diopside.
基金funded by grants from Sinoprobe-05-02 from the Ministry of Science and Technology of Chinathe NSF China (Nos. 40930313, 40921001, 41202036)+1 种基金the China Geological Survey (Nos. 1212011121263, 12120114061801, 2014DFR2127C)project from Institute of Geology, Chinese Academy of Geological Sciences (J1526)
文摘The ultramafic massif of Bulqiza, which belongs to the eastern ophiolitic belt of Albania, is the most important area for metallurgical chromitite ores. The massif consists of a thick （〉4 km） rock sequence, with a generalized profile from the bottom to the top as follows. The tectonite sequence composed mainly of harzburgites with subordinate intercalations of dunites,
