Alexandre Raphael Cabral, José Maria Leal, Rogerio Kwitko-Ribeiro
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引用次数: 0
Abstract
Gold nuggets, loose in talus material, triggered an ongoing gold rush in the southern Serra do Espinhaço, Minas Gerais, Brazil. The talus material has abundant fragments of vein quartz in a clay-rich matrix, resting on metagreywacke of the Neoproterozoic Macaúbas Group. Quartz lodes, which truncate the metamorphic foliation of the bedrock metagreywacke, are the source of the gold nuggets, which formed after the main tectonic and metamorphic overprint of the Ediacaran–Cambrian Brasiliano orogeny. The gold nuggets are hypogene in origin, but they have a minor component of supergene gold, which occurs as dendrites of bud-like gold particles, mostly <1 µm across. Amongst the latter, apically branched hyphae of essentially pure gold are noteworthy and suggest pseudomorphism after fungi.
摘要巴西米纳斯吉拉斯州南部塞拉杜埃斯平哈索（Serra do Espinhaço）的金块散落在距骨材料中，引发了持续不断的淘金热。距石材料中有大量的脉石英碎片，基质富含粘土，位于新新生代马考巴斯组的岩屑岩上。在埃迪卡拉纪-寒武纪巴西里亚诺造山运动的主要构造和变质叠压作用之后形成的石英矿脉截断了基岩玄武岩砾岩的变质褶皱，是金块的来源。金块的来源是次生金，但其中有少量超生金，以芽状金粒的树枝状出现，直径大多为 1 微米。在后者中，值得注意的是顶端分枝的基本上是纯金的菌丝，这表明它们是仿真真菌的假形态。
期刊介绍：
Geology of Ore Deposits is a periodical covering the topic of metallic and nonmetallic mineral deposits, their formation conditions, and spatial and temporal distribution. The journal publishes original scientific articles and reviews on a wide range of problems in theoretical and applied geology. The journal focuses on the following problems: deep geological structure and geodynamic environment of ore formation; distribution pattern of metallogenic zones and mineral deposits; geology and formation environment of large and unique metallic and nonmetallic deposits; mineralogy of metallic and nonmetallic deposits; physicochemical and isotopic characteristics and geochemical environment of ore deposition; evolution of ore-forming systems; radiogeology and radioecology, economic problems in exploring, developing, and mining of ore commodities.
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