Study of Carbon-Bearing Particles in Ascending Geogas Flows in the Dongshengmiao Polymetallic Pyrite Deposit, Inner Mongolia, China

Abstract

Samples of ascending geogas flow particles were collected on to SiN grids directly in the Quaternary sediments overlying the Dongshengmiao polymetallic pyrite deposit, China. Corresponding soil samples were collected in the surface of Dongshengmiao district at the same time. After pretreatment, these SiN grid samples were analyzed by transmission electron microscopy. The tests focused on the characteristics of particles including size, shape, chemical composition, structure and association. The results show that there are numerous carbon-bearing particles in particulate samples of the ascending geogas flow. The particles contain organic matter, carbonate or carbonate mixed with other minerals. These carbon-bearing particles generally contain metallic elements like Fe/Zn/Au/Cu/Pb. However, all of the soil particles do not contain elemental C and only consist of common elements (O, Na, Mg, Al, Si, Ca, Ti) just like the composition of earth crust. Through a comparison between the particles from different sources, the carbon-bearing particles were found to come only from the deep earth and carried useful information about concealed deposits as they pass through the deep-seated orebodies. Given the influences of organic matter on mineralization, the carbon-bearing particle may provide information on the deposit genesis. Combining the use of geogas particle for prospecting with characteristics of large depth, and the carbon-bearing materials' close spatial and genetic relationship with orebodies, we propose a new prospecting method based on the characteristics of carbon-bearing particles, including morphology, size, chemical component and ultra-microstructure. This approach could be applied to the exploration of deposits deep in the earth and abundant in carbon-bearing matter. This approach can provide efficient and effective deposit exploration. Through analyzed the characteristics of carbon-bearing particles in ascending geogas flow samples which collected in the Dongshengmiao polymetallic pyrite deposit and tested by TEM, the particles were found to come from deep earth and carry useful information about concealed deposits. Thus a new efficient prospecting method based on the characteristics of carbon-bearing particles was proposed.