Paper No. 49-4
Presentation Time: 9:00 AM-5:30 PM
DIAMONDS AND MOISSANITE FROM THE ALADAG OPHIOLITE OF THE EASTERN TAURIDE BELT, SOUTHERN TURKEY: A FIRST REPORT
The Aladag ophiolite in the eastern Tauride belt, southern Turkey, is a well-preserved remnant of oceanic lithosphere. It consists of, in ascending order, harzburgitic to dunitic tectonites, ultramafic and mafic cumulates, isotropic gabbros, sheeted dikes and basaltic pillow lavas. Podiform chromitites are common in the mantle peridotites. Thus far, more than 200 grains of microdiamond and more than 100 grains of moissanite (SiC) have been separated from one sample of podiform chromitite. The microdiamonds occur mostly as subhedral to euhedral, colorless to pale yellow grains, about 50-300 μm in size. Moissanite grains are generally subhedral, light blue to deep blue in color and variable in size. These grains of diamond and moissanite are very similar to in-situ grains in podiform chromitites of Tibet and the Polar Urals of Russia (Yang et al., 2014; 2015), indicating that they are natural minerals, not the result of natural or anthropogenic contamination. As reported elsewhere, the diamonds and moissanite are accompanied by a range of other minerals, including rutile, zircon, quartz and sulfides. The discovery of diamond, moissanite and other unusual minerals in the podiform chromitites of the Aladag massif provide additional evidence for the widespread occurrence of these minerals in ophiolites, indicating that they are related to global mantle processes.
Fahui Xiong and Wenda Zhou assisted with the fieldwork in Turkey. This work is funded by grants from the Ministry of Science and Technology of China (2014DFR21270), China Geological Survey (12120115026801,12120115027201, 201511022) and the Fund from the State Key Laboratory of Continental Tectonics and Dynamics (Z1301-a20).
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