TIAN Yazhou
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.YANG Jingsui
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.Paul T. ROBINSON
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.XIONG Fahui
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.LI Yuan
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.ZHANG Zhongming
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.LIU Zhao
2 Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, ChinaLIU Fei
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.NIU Xiaolu
1 CARMA, State Key Laboratory for Continental Tectonics and Dynamics, Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China.This research was funded by grants from the National Natural Science Foundation of China (No. 40930313), the Ministry of Land and Resources of the People’s Republic of China (No. 201011034) and the China Geological Survey (No. 12120114057701, No. 12120114061801 and No. 12120114061501).
In recent years diamonds and other exotic minerals have been recovered from mantle peridotites and high-Cr chromitites of a number of ophiolites of different age and different tectonic environments. Here we report a similar collection of minerals from the Sartohay ophiolite of Xinjiang Province, western China, which is characterized by having high-Al chromitites. Several samples of massive podiform chromitite with an aggregate weight of nearly 900 kg yielded diamonds, moissanite and other highly reduced minerals, as well as common crustal minerals. Thus far, more than 20 grains each of diamond and moissanite have been recovered from heavy mineral separates of the chromitites. The diamonds are all 100-200 μm in size and range in color from pale yellow to reddish-orange to colorless. Most of the grains are anhedral to subhedral octahedra, commonly with elongate forms exhibiting well-developed striations. They all display characteristic Raman spectra with shifts between 1325 cm?1 and 1333 cm?1, mostly 1331.51 cm?1 or 1326.96 cm?1. The moissanite grains are light blue to dark blue, broken crystals, 50-150 μm across, commonly occurring as small flakes or fragments. Their typical Raman spectra have shifts at 762 cm?1, 785 cm?1, and 966 cm?1. This investigation extends the occurrence of diamonds and moissanite to a Paleozoic ophiolite in the Central Asian Orogenic Belt and demonstrates that these minerals can also occur in high-Al chromitites. We conclude that diamonds and moissanite are likely to be ubiquitous in ophiolitic mantle peridotites and chromitites.
TIAN Yazhou, YANG Jingsui, Paul T. ROBINSON, XIONG Fahui, LI Yuan, ZHANG Zhongming, LIU Zhao, LIU Fei, NIU Xiaolu.2015. Diamond Discovered in High-Al Chromitites of the Sartohay Ophiolite, Xinjiang Province, China[J]. Acta Geologica Sinica(),89(2):332-340
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