Scholarlink

<p>Ethiopian orogenic mesothermal gold and associated metallic mineral deposits occur within the greenstone ophiolitic fold and thrust belt of brittle-ductile shear zones. However, details of the gold and base metal mineral potential have not been well investigated in the Ropi Megada valley, west Guji, Ethiopia. This study, therefore, characterizes the gold and base metal mineral potential in the study area. Among the collected samples, 12 gold fire assays, 11 gold mineralogical physical studies, and 12 ore mineral analyses were determined using Inductively Coupled Plasma-Mass Spectrometry, Stereo Microscope, and Ore Microscope, respectively. The study of geology includes quartz-feldspathic gneiss, biotite gneiss, garnet-biotite schist, amphibole-biotite schist, granodiorite, and K-feldspar-rich granite rocks. Ore mineralogy assemblages in the mafic schists occurred within the narrow, N-S trending, and brittle-ductile shear zones. Pyrite deformation contained inclusions of chalcopyrite and sphalerite that were genetically younger than pyrite. The gold and base metal concentrations are situated in the central and southeastern parts near the brittle-ductile shear zone. The base metals and trace elements associated with Au include Cu, Zn, Pb, Co, Ni, Sc, Mo, Li, Tl, Cd, Ag, and As. The Au concentration anomaly was categorized as low (0.001 to 0.039 ppm), moderate (0.03901 to 0.176 ppm), and high (0.17601 to 0.489 ppm). Among these, the Au range of 0.001 to 0.489 ppm is deposited in the amphibole-biotite schist. The gold grain sizes ranged from fine to coarse and mostly showed angular and sub-angular morphology, indicating that the primary gold is located near the study area. The gold crystals were associated with quartz, ilmenite, rutile, tourmaline, magnetite, and calcite. The gold fire assay chemistry compositions were dominated by Au (0.13), Cu (43.43), Zn (74.99), Ni (324.43), Co (48.48), Sc (24.43), Li (15.54), Tl (4.17), Pb (3.6), As (1.25), and Ag (0.13) ppm. This study in the Ropi Megada valley demonstrated that the potential area for gold, base metals, and trace element mineralization is evidently associated with the hydrothermal type along the brittle-ductile deformation in the amphibole-biotite schist rock suites as a result of orogenic metamorphism and subordinate mafic magmatic fluid that originated from the nearby source rocks.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Gold and base metal potential assessment and evaluation in the Ropi Megada valley, West Guji, Southern Ethiopia

  • 期刊论文

  • 发表日期：

    2026年1月16日

查看全文
  • Bekele Ayele

摘要

Ethiopian orogenic mesothermal gold and associated metallic mineral deposits occur within the greenstone ophiolitic fold and thrust belt of brittle-ductile shear zones. However, details of the gold and base metal mineral potential have not been well investigated in the Ropi Megada valley, west Guji, Ethiopia. This study, therefore, characterizes the gold and base metal mineral potential in the study area. Among the collected samples, 12 gold fire assays, 11 gold mineralogical physical studies, and 12 ore mineral analyses were determined using Inductively Coupled Plasma-Mass Spectrometry, Stereo Microscope, and Ore Microscope, respectively. The study of geology includes quartz-feldspathic gneiss, biotite gneiss, garnet-biotite schist, amphibole-biotite schist, granodiorite, and K-feldspar-rich granite rocks. Ore mineralogy assemblages in the mafic schists occurred within the narrow, N-S trending, and brittle-ductile shear zones. Pyrite deformation contained inclusions of chalcopyrite and sphalerite that were genetically younger than pyrite. The gold and base metal concentrations are situated in the central and southeastern parts near the brittle-ductile shear zone. The base metals and trace elements associated with Au include Cu, Zn, Pb, Co, Ni, Sc, Mo, Li, Tl, Cd, Ag, and As. The Au concentration anomaly was categorized as low (0.001 to 0.039 ppm), moderate (0.03901 to 0.176 ppm), and high (0.17601 to 0.489 ppm). Among these, the Au range of 0.001 to 0.489 ppm is deposited in the amphibole-biotite schist. The gold grain sizes ranged from fine to coarse and mostly showed angular and sub-angular morphology, indicating that the primary gold is located near the study area. The gold crystals were associated with quartz, ilmenite, rutile, tourmaline, magnetite, and calcite. The gold fire assay chemistry compositions were dominated by Au (0.13), Cu (43.43), Zn (74.99), Ni (324.43), Co (48.48), Sc (24.43), Li (15.54), Tl (4.17), Pb (3.6), As (1.25), and Ag (0.13) ppm. This study in the Ropi Megada valley demonstrated that the potential area for gold, base metals, and trace element mineralization is evidently associated with the hydrothermal type along the brittle-ductile deformation in the amphibole-biotite schist rock suites as a result of orogenic metamorphism and subordinate mafic magmatic fluid that originated from the nearby source rocks.