Electrical, mineralogical, and geochemical properties of Um Gheig and Um Bogma Formations, Egypt

• Mohamed M. Gomaa ^[1] ; Esmat A. Abou El-Anwar ^[1]
  1. [1] National Research Centre

     National Research Centre

     Egipto

     
• Localización: Carbonates and Evaporites, ISSN 0891-2556, Vol. 34, Nº. 4, 2019, págs. 1251-1264
• Idioma: inglés
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• Resumen

  • Dolostones of Um Bogma and Um Gheig Formations were studied using mineralogical and geochemical characterizations. The present work has tried to identify the origin, environment, pollution, and their electrical properties for the two formations. Also, the environmental geochemistry that resulted from the trace element concentration is examined here and we will try to differentiate between them. The study samples are fissile and highly fossiliferous dolomites. The two formations are classified as dolostones and nearly ordered. The mineralogy and geochemistry studies indicated that the two formations were formed under mixing zone at the near-surface oxidizing environment. The diagenetic features of both formations demonstrate many processes with clear effects. Dolostones of both formations may be precipitated from two different solutions. Meteoric water is the main supply, while the other solution may be resulted from the deep hydrothermal solutions that come up from deep faults. The distribution of Sr and Y content of dolostones at Um Bogma Formation indicated that they are precipitated at 110–150 °C, while those in Um Gheig are deposited at <150 °C. Electrical properties were measured at ~21 °C and humidity ~55% in a frequency range of 42 Hz–5 MHz. Slight changes were seen to be the result of changes in texture between grains and mineral composition for the two formations. The most effective factor in the changes of electrical properties is the distribution of grains (texture). The dielectric constant, generally, decreases with the decrease of discontinuous paths and frequency. Electrical conduction, usually, increases with the increase of conductor continuous paths and frequency.