A New Occurrence of （Gold-Bearing） Graphite in the Assosa Region, BenishanguI-Gumuz State, W Ethiopia  

作　　者：Liam A. Bullock Owen J. Morgan 

机构地区：[1]School of Geoscienees, University of Aberdeen, Aberdeen, AB24 3UE, United Kingdom [2]Tactical Environmental Response, Yorkshire, LS29 9BZ, United Kingdom

出　　处：《Journal of Earth Science and Engineering》2015年第7期417-435,共19页地球科学与工程（英文版）

摘　　要：The Assosa region of western Ethiopia hosts newly discovered and potentially highly economic graphite-bearing schist units. Due to its unique physical and chemical properties, graphite is quickly becoming an increasingly important economic resource. Graphite occurs over much of the area, and is hosted predominantly by quartz-graphitic schist, quartz-feldspar-mica schist and quartzite. The quartz-graphitic schist covers an area of 37 km2, forming steep valleys and ridges across a 190 km long belt. Graphite is texturally-variable within and across units. Crystal habit varies from highly crystalline to irregular flakes. Flake sizes range from amorphous and crystalline small flake to coarse large flake （〉 150 p.m）, with beneficiation of- 70% and yield potential of 〉 95% （froth flotation methods）. The license area is already a well-known gold-hosting area, and potentially economic gold deposits occur within the graphite-bearing units. Overall, the site shows excellent geochemical indicators, field observations and historical accounts of high gold content. It is suggested that textural variations may be the product of （1） early in-situ formation during （early- to late-Proterozoic） prograde metamorphism and （2） later vein-type mineralization during retrograde metamorphism. The discovery of graphite in western Ethiopia is the first documented and preliminary studies suggest a high economic potential for the deposits.

关 键 词：GRAPHITE GOLD METAMORPHISM X-ray fluorescence X-ray diffraction. 

分 类 号：P618.510.5[天文地球—矿床学] TS934.3[天文地球—地质学]