• Geophysics and Geophysical Exploration
• /
• v.17 no.3
• /
• pp.147-154
• /
• 2014

For analyzing the distribution of chromite, magnetic survey was carried out on the chromium mineralized belt in Bophi Vum area, northwestern Myanmar. As a result, the magnetic susceptibility of chromite is lower than those of dunite and harzburgite, which are background rocks of chromite. Also, the locations of low magnetic anomaly zone and low magnetic susceptibility models of 3D magnetic inversion result are spatially well matched with those of chromite occurrences confirmed by the surface geological survey and trench survey. Some of low magnetic effects are expanded to the periphery area of chromite occurrences. Considering the magnetic susceptibility characteristics of various rocks in this area, the expanded low magnetic anomaly zones are estimated as the high potential areas bearing chromite. For confirming the potential area of chromite pointed by coarse magnetic survey, the additional detail exploration need to be carried out in future.

• Economic and Environmental Geology
• /
• v.47 no.4
• /
• pp.351-362
• /
• 2014

In order to grasp the geological characteristics, the occurrence mode of ore body and development potential of Bophi Vum chromite mineralized zone in northwestern Myanmar, Korea Institute of Geoscience and Mineral Resources(KIGAM) and Department of Geological Survey and Mineral Exploration(DGSE) carried out joint exploration targeting on the $6km^2$ areas within the mineralized zone. Chromitites occur as a major Cr-ore body in the Bophi Vum area, and are enveloped by dunitic peridotites. As a result of geological survey, the geological map of Bophi Vum was drawn in the scale of 1:1,000, and we discovered that the chromitite ores are mainly distributed at the elevation range between 200 and 400 m. The soil geochemistry was conducted by collecting total 114 soil samples in the interval of 50 m after pitting ground surface under 0.7-1 m. Geochemical anomaly maps of Cr, Ni, Fe, and Mn were prepared by ICP-AES.

• Economic and Environmental Geology
• /
• v.50 no.6
• /
• pp.423-433
• /
• 2017

Korea Institute of Geoscience and Mineral Resources and Department of Geological Survey and Mineral Exploration in Myanmar have explored the Kalaymyo chromitite deposit, Myanmar since 2013. It is now necessary to find a geochemical indicator for efficient mineral exploration in the future and building a 3D geological model for this ore deposit. Mantle podiform chromitite is a major type of Cr ore in this region, which is considered to be formed by mantle-melt interaction beneath the mantle-crust boundary of oceanic lithosphere. In this study we measured major element composition of spinels in harzburgite, dunite and chromitite, and examined the hypothesis that spinel Cr#(molar Cr/(Cr+Al)${\times}$100) can be used as a geochemical indicator in exploration for the Kalaymyo chromitite. The results show that there is a clear correlation between spinel Cr# and distribution of chromitite. The spinel Cr# of harzburgite increases with decreasing the distance from the chromitite bodies. The spinel composition is also closely associated with texture and occurrence of spinels. The high Cr# spinels (30-48) are subhedral to euhedral and enclosed by olivine whereas the low Cr# spinels (16-27) are anhedral and commonly associated with pyroxenes. Often the low Cr# spinels show symplectite intergrowths with pyroxenes, indicating their residual nature. These petrological and geochemical results suggest that the high Cr# spinels have resulted from mantle-melt interaction. We suggest that spinel Cr# can be used as a geochemical indicator for Cr ore exploration and as one of critical factors in 3D geological model in the Kalaymyo chromitite deposit.