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The Discovery of Diamonds in Chromitites of the Hegenshan Ophiolite, Inner Mongolia, China
Author(s) -
Zhu HUANG,
Jingsui YANG,
ROBINSON Paul T.,
Yongwang ZHU,
Fahui XIONG,
Zhao LIU,
Zhongming ZHANG,
Wei XU
Publication year - 2015
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.12434
Subject(s) - ophiolite , chromite , geology , geochemistry , chromitite , zircon , paleontology , tectonics
Diamond, moissanite and a variety of other minerals, similar to those reported from ophiolites in Tibet and northern Russia, have recently been discovered in chromitites of the Hegenshan ophiolite of the Central Asian Orogenic Belt, north China. The chromitites are small, podiform and vein‐like bodies hosted in dunite, clinopyroxene‐bearing peridotite, troctolite and gabbro. All of the analysed chromite grains are relatively Al‐rich, with Cr # [100Cr/(Cr+Al)] of about 47–53. Preliminary studies of mainly disseminated chromitite from ore body No. 3756 have identified more than 30 mineral species in addition to diamond and moissanite. These include oxides (mostly hematite, magnetite, rutile, anatase, cassiterite, and quartz), sulfides (pyrite, marcasite and others), silicates (magnesian olivine, enstatite, augite, diopside, uvarovite, pyrope, orthoclase, zircon, sphene, vesuvianite, chlorite and serpentine) and others (e.g., calcite, monazite, glauberite, iowaite and a range of metallic alloys). This study demonstrates that diamond, moissanite and other exotic minerals can occur in high‐Al, as well as high‐Cr chromites, and significantly extends the geographic and age range of known diamond‐bearing ophiolites.