T80 Investigations of Hydrothermal Systems: Advances and Challenges

Monday, 23 September 2019
8:00 AM - 12:00 PM
Room 222BC, North Building

HYDROTHERMAL GOLD IN PERMIAN BLACK SHALE KUPFERSCHIEFER - A HOT HYDROTHERMAL EXTRUSION MEETS THE EUXINIC ZECHSTEIN SEA AT 252 MA

Paper number: T80-5
Program: Technical Sessions
Time: 8:55 AM – 9:10 AM

Authors

Abstract

Detecting gold (Electrum AuAg) exsolutions in hot hydrothermal copper minerals in Permian Kupferschiefer is in the case of the European Kupferschiefer a paradigm change, with consequences.

During the late Permian, the Zechstein sea covered more than 600,000 km2 with a centimeter thick layer of siliceous to carbonaceous euxinic sediments summarily called the Kupferschiefer. At the southern margin of the sea extends the European Copper Belt, on top of a Variscan basement with a failed rifting zone, over more than 750 km west to east, where today the Kupferschiefer with its associated polymetallic and precious metals is mined at a volume of about 500,000 tons of Cu metal per annum.

The paradigm change is the detection of precious metals (Au, Ag) in hot hydrothermal digenite, bornite and chalcocite copper minerals causing the abandonment of the low energy synsedimentary – low temperature epigenetic depositional concept. Active hydrothermal brine emplacement from deep sourced open systems caused large scale metal, hydrocarbon and chemical mud slurry intrusions and extrusions in the shallow Kupferschiefer sea making it to be hostile to life, contributing to the Permian extinction event. New exploration, geological, geophysical, mineralogical, geochemical and sulfur isotope data support this model, that can be proven in the high grade Zechstein Kupferschiefer mines of Rudna, Lubin, Polkowicze, Mansfeld, Sangerhausen, Richelsdorf and has led to the discovery of the Cu-Ag-Au Spremberg deposit, Germany.

Some of the new research results:

  • Much of the productive Kupferschiefer is an amorphous siliceous-calcareous, hydrocarbon, metal rich slurry mud
  • Gold and silver are primary constituents of the copper mineralization associated with hydrocarbons and are of hot hydrothermal origin
  • The Zechstein Weissliegend sands belong to the hydrothermal system, are extrudites, and carry large volume and high grade primary copper mineralization
  • The depositional model is: open seeps of hot hydrothermal hydrocarbon-metal carrying slurry mud brines extruding on a shallow sea floor causing it to be hostile to life
  • Existing exploration (Spremberg, Germany) and mining activities (Lubin, Rudna, Poland) are confirming this new hydrothermal-dynamic resource model.

Geological Society of America Abstracts with Programs. Vol. 51, No. 5

doi: 10.1130/abs/2019AM-339326

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