Geochemical Characteristics of Metamorphic Rock-Hosted Gold Deposit At Onzon-Kanbani Area, Central Myanmar

Gold and associated base metal mineralization of Onzon-Kabani area located in the western border of generally N-S trending Mogoke Metamorphic Belt where well-known Sagaing fault is served as a western boundary of this area. In this research area, many artisanal and small-scale gold mines were noted in last three decades. Gold mineralization is hosted in marble and gneiss unit of research area but most common in marble unit. Variety of igneous intrusions are also observed in research area. Mineralizations are observed as fissure filling veins as well as lesser amount of disseminated nature in marble unit. Mineralogically, gold are associated with other base metal such as pyrite, galena, sphalerite, chalcopyrite, marcasite and arsenopyrite. Hydrothermal alteration halos are developed in peripheral of hydrothermal conduits or mineralization veins from proximal to distal such as 1) silicic, 2) sericite-illite, and 3) propylitic alteration.  Most of hydrothermal minerals from each altered zones showed that near neutral condition of pH (e.g. adularia, calcite, illite, sericite and chlorite). Alternatively, hydrothermal alteration zones that show with ore minerals such as native gold, electrum, sphalerite, galena, chalcopyrite, arsenopyrite and marcasite which mostly observed in silicic alteration zone. Typical boiling characters of vein textures and fluid inclusion petrography are observed in hydrothermal system of research area. Boiling, cooling and mixing are possiblily responsible for gold deposition in hydrothermal system. In this paper, authors are documented to clarify the type of mineralization based on hydrothermal alterations, ore and gangue mineral assemblages and fluid inclusion study. All of these data can describe and play an important role for both with respect to understanding deposit genesis and in mineral exploration

A comprehensive assessment of ground motions from two 2016 intra-slab earthquakes in Myanmar

We map the distribution of macroseismic intensities from the MW 6.9 Kani and the MW 6.8 Chauk intra-slab earthquakes in 2016 in Myanmar using the 1998 European Macroseismic Scale (EMS-98) by interpreting data gathered from field surveys, community responses sent via social media to the Myanmar Earthquake Committee (MEC), and digital news reports. Our macroseismic maps for both events provide better spatial data coverage in Myanmar, India, and Bangladesh than community derived macroseismic maps (e.g., U.S. Geological Survey's “Did You Feel It?”). In Myanmar, this was driven by improved telecommunication that has allowed social media such as the Burmese language Facebook portal of the Myanmar Earthquake Committee (MEC) to reach into rural areas from where reports of shaking effects from earthquakes have been previously unavailable. Our analysis of both the macroseismic intensities and strong motion observations from India and Myanmar suggests the two earthquakes had different source properties. The comparison of our intensity data with instrumental strong motion records also suggests the peak ground motion-intensity relationship by Worden et al. (2012) generally performs well for both earthquakes. In addition, ground motion behaviour within the Burma and Indian plates can be related to different existing ground motion prediction equations (GMPEs) and intensity prediction equations (IPEs) for subduction zones and for stable continental regions respectively. We therefore suggest these effects will need to be considered in future regional seismic hazard models or Shake Maps for this region when evaluating the impact of the future events.NRF (Natl Research Foundation, S’pore)MOE (Min. of Education, S’pore)Published versio