**1. Introduction**

The Kupferschiefer is a copper-, polymetallic-, hydrocarbon-bearing black shale of the lowermost Zechstein Group of Permo-Triassic age (252 Ma) in southern Germany and southwestern Poland [1, 2]. It is usually one to two-meters thick and

underlies 600,000 square kilometers, extending from Great Britain to Belarus for a distance of over 1500 km (**Figure 1**).

Copper has been mined from the Kupferschiefer for over 800 years, since its discovery circa 1200 A.D. The top of the Kupferschiefer carbonaceous shale unit coincides with the Permian extinction event and the Permo-Triassic unconformity dated at circa 252 Ma [1, 2]. The brines that deposited the Kupferschiefer metal system were extremely toxic and reduced and may have significantly contributed to the Permian extinction event [3].

Mineralogical, chemical, and geological analyses of the combined Kupferschiefer-Zechstein show strong chemical and paragenetic relationships between the Weissliegend silica extrudites (sandstones), Kupferschiefer carbonaceous shales, and Zechstein salines and dolomitic carbonates. This linkage has led us to a broader, more unified, serpentine-linked model related to deep-sourced, hot, hydrothermal, mud-brine volcanism [1, 2]. The overall Zechstein-Kupferschiefer chemical stratigraphy suggests density- and composition-driven fractionation of deep-sourced, high-density brines that are metal-rich, alkali-rich, silica-aluminumrich, and halogen-rich.

The Kupferschiefer-Weissliegend contains a world-class copper resource with most of the copper hosted in the Weissliegend. More than 78 million metric tons (Mt) of copper have been produced or delineated as resources, with more than 90 percent of the known mineral endowment located in Poland [4]. Salt resources in the immediately overlying Zechstein saline sequence are also world-class with 102 billion metric tons of economic and subeconomic salt in Poland alone [5]. The salt deposits also contain major resources of magnesium and potassium along with elevated strontium, boron, and lithium [6].

#### **Figure 1.**

*Map of Zechstein basin showing locations of exotic magnesium minerals, lithium-rich brines, and euhedral quartz [1]. [Li = lithium-rich brines; T = talc; S = serpentine; C = clinochlore; Q = euhedral quartz]. From west to east (left to right), the locations are Yorkshire, England [TCQ], Emsland, southwest Germany [STC], Mors diapir, northern Denmark [Q], Gorleben salt dome north central Germany [Li,T], Morsleben salt dome [Li,S,C], Königschall, Hindenburg salt mine, southern Germany [C], dolomite 'reef'. Red x crosses are mines: 1 = Melsungen, 2 = Sangerhausen, 3 = Mansfeld, 4 = Spremberg, 5 = Konrad, 6 = Polkowice-Sieroszowice, 7 = Rudna, and 8 = Lubin.*

*Generation of Mud Volcanic Systems Sourced in Dehydrated Serpentospheric Mantle DOI: http://dx.doi.org/10.5772/intechopen.105689*
