Известия Томского политехнического университета: Инжиниринг георесурсов (Mar 2019)

MORPHOLOGY AND COMPOSITION OF GOLD IN WEATHERING CRUST OF THE TOM-YAYA INTERFLUVE

  • Olga M. Yanchenko,
  • Valery G. Voroshilov,
  • Timofey V. Timkin,
  • Irina V. Martynenko,
  • Mansour Ziaii

DOI
https://doi.org/10.18799/24131830/2019/3/166
Journal volume & issue
Vol. 330, no. 3
pp. 84 – 92

Abstract

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Relevance. Weathering crusts of rocks of the Paleozoic basement of the Tom-Yaya interfluve are potential targets for commercial extraction of readily recoverable gold. But the morphology and composition of this gold are very poorly studied, which makes it difficult to assess the already identified ore occurrences and determines the relevance of the work performed.The main aim of the research is to investigate chemical composition and morphological features of native gold in weathering crust profile of the Tom-Yaya interfluve. Object: native gold in weathering crusts according to the rocks of the Paleozoic basement of the Tom-Yaya interfluve. Methods. Composition, crystallomorphological features of gold, paragenetic associations with ore and vein minerals were analyzed microscopically under a binocular, in reflected light, by inductively coupled plasma-atomic emission mass spectrometry (ICP-AES/MS) and on a scanning electron microscope TESCAN VEGA 3 SBU with EMF OXFORD X-Max 50, X-ray fluorescence microscope HORIBA Scientific XGT-7200. Results. Two forms of gold were found in weathering crusts and primary ores – free and bound (invisible) gold. The authors have determined chemical composition and the sample of primary and hypergenic gold are determined. The decrease in the content of impurity elements and the increase in the strength of hypergenic gold in comparison with the gold of primary mineralization were found. The authors established the main morphological types of gold for different parts of weathering crust section. The presence of hypergene gold of «bacteriomorphic» origin is assumed. All gold varieties are associated with hypergene minerals (carbonates, clay minerals, iron hydroxides). The highest gold content is characteristic for the upper part of the section of the weathering crust - the zone of hydrolysis of residual weathering crust and redeposited weathering crust.

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