The deposit Pöhla-Globenstein

The deposit Pöhla-Globenstein is geologically located in the western part of the Ore Mountains belonging to the anticline area of Fichtel Mountains and Ore Mountains which marks the southern border of the Schwarzenberg gneissic dome lying in the influence area of the Gera-Jáchymov fault zone with the supra-regional NW-SE course of veins.

The geological frame of the deposit is mainly crystalline shale of the late Proterozoic and the Cambrian (mica slate, quartzite, Amphibolites) resting on Upper Carboniferous/under Permian Granites of the Variscan Pluton from the Ore Mountains (fractionated Pluton of the Western Ore Mountains) and/or is opened in local swellings by these granites. 


In the immediate deposit area, there are metamorphic rocks of the lower Cambrian Raschau formation of the Keilberg Group in place. This rock succession consists mainly of mica shale with several skarn and meta-carbonaceous rock horizons which incline to the south east in case of a SW-NE course of veins.


The approx. 200 to 250 m thick downcast group and the max. 300 to 400 m thick hanging group of the Raschau formation consists mainly of mica slates and/or gneissic mica slates with phacoides of amphibolites; rarely, small embeddings of skarned marbles as well as graphite and sulphide bearing slates can be found. 


The average group of the Raschau formation is 300 to 500 m thick and shows a relatively higher diversity of rocks:

  • Slates of different kinds (mica slate, partly feldspathic greywacke or granite bearing, quartzitic slates)
  • Meta-carbonaceous rocks (marble, particularly dolomitic; skarns with transition belts)
  • Amphibolites
  • Quartzites
  • Gneissic muscovites, and others

The percentage of the individual rocks differs spatially quite considerably. The high content of carbonaceous rocks in this group reaching up 50% sometimes is particularly considerable. 


Connected to these skarned rock horizons (skarn deposits) is a tin-tungsten mineralization. Due to the metal content (iron, tin, tungsten, copper), the skarn deposit of Pöhla-Globenstein is designated as a complex deposit. 


There are 5 consecutively numbered skarn-meta-carbonaceous rock horizons, from downcast to hanging, to be distinguished and the upper three of which contain the ore deposits no. 5, 4, and 3 with polymetallic mineralization in exploitable quality. 


The deposit zone is characterised by a cross folding of brittle structures, mainly in the NW-SE course of veins (e. g. Luchsbach faults I and II, Schwarzenberg fault) and the NE-SW course of veins (e. g. Arnoldshammer fault with 2 subparallel main fault branches; Globenstein fault).


Ore deposit 3


About one third of the tin mineralization is concentrated within the ore deposit 3 (the so-called carbonaceous rock/skarn horizon) of the Pöhla-Globenstein deposit. The tin mineralization is predominantly linked to skarns and subordinately bound to the neighbouring crystalline shale. Mainly mineralized are low aged pyroxene skarns (skarn ores, about 85%) and mica shale (about 15%).


The main ore mineral of the ore deposit 3 is cassiterite, often occurring in the skarn together with chloride, sericite, and fluorspar as gab fillers. Cassiterite can also be found as megacrysts in skarn minerals, occurrence on micro-stringers is rare. Tungsten minerals are rare in the ore deposit 3.


The ore deposit 3 in the approx. 4 to 10 m thick carbonaceous rock/skarn horizon is approx. 2 to 6 m thick and reaches a maximum thickness of 10 to 15 m. The numerous extended lenticular ore bodies reach dimensions between 15 m and 250 m.


The following types of ore can be found in the ore deposit 3:

  • Skarn ore: approx. 44%
  • Shale: approx. 40%
  • Decomposition ore: approx. 9%
  • Greisen ores: approx. 7 %

The highest ore thickness of the deposit 3 is formed within the skarns and in the transition zones skarn/carbonaceous rock. The inclination of the sheeted ore body changes from 35° to nearly 0°.


Ore deposit 4


In the ore deposit 4 (in the 4th carbonaceous rock/skarn deposit, also designated as the “main deposit”) is the main quantity of the tungsten mineralization and also the predominant part of the tin mineralization (55%) of the deposit are concentrated. The tin mineralization of the ore deposit 4 is normally spaced apart from the tungsten mineralization. While the tungsten ores mainly exist in the decomposed carbonaceous rocks, the tin mineralization is bound to skarns. The tungsten mineralization in the ore deposit 4 is bound to approx. 80% to scheelite and to approx. 20% to hubnerite. The form of the ore body is depending on the inclination of the layers and the stringer leads. In parallel paths, bigger ore bodies have developed, in acute-angled paths, the ore bodies are smaller. The following types of ore can be found in the ore deposit 4:

  • Decomposition ore: approx. 48%
  • Greisen ore: approx. 21%
  • Skarn ore: approx. 18%
  • Shale: approx. 13%

The decomposition ores of the deposit 4 can be distinguished, according to the norm, into:

  • a fluorspar-mica variety (= scheelite ore) with a high fluorspar content (often 20%), a high scheelite content and scheelite grains on 0.1 to 1 mm, nearly tungsten-free, and
  • a clay-hydromica variety (= scheelite-tungsten ore) with a low fluorspar content (mostly 6%) and a higher tungsten content (25% to 50%).

Fluorspar is the most common companion of tungsten ore and can be found widespread in all intensively aged and often highly decomposed carbonaceous rocks with a content of 1% to 40%.


Ore deposit 5


The ore deposit 5 is stratigraphically located in the upper part of the 5th carbonaceous rock/skarn horizon near the back limit of the Raschau formation. Geographically located in the North-East part of the deposit, the dominating tungsten mineralization of the deposit 5 corresponds in general to that one of the ore deposit 4.


The situation and the morphology of the ore body in the ore deposit 5 are determined structurally (by the Arnoldshammer fault with quartz-scheelite-fluorspar zone of stringers) and lithologically (by the carbonaceous rock horizons). The lenticular/in beds occurring or irregular, even steep-standing scheelite ore bodies are bound to intersection zones of closely spaced zones of stringers in the relatively thick and predominantly carbonaceous rocks. The main ore mineral of the deposit 5 is scheelite with a total ore portion of about 90%. The medium grain size of the scheelite in the deposit 5 is 1.9 mm. The scheelite is predominantly combined with fluorspar, quartz as well as sericite, hydro-mica, and clay mineral. Tungsten had been found in the ore deposit 5 only rarely and only in association with quartz, occasionally with pyrite and arsenopyrite. 


Beyond that, fluorspar is the most important secondary raw material in the ore deposit 5 with an average of 15% to 30% in the ore ranges. 


The ore of the deposit 5 is available to approx. 60% as consolidated ore and to 40% as decomposed ore.

About SME AG

Saxony Minerals & Exploration AG – SME AG is a stock company that obtained the mining rights and permit to extract the mineral resources tungsten, tin, indium, and other metals.


Saxony Minerals & Exploration AG - SME AG
Schwarze Kiefern 2
09633 Halsbrücke, Germany
Tel.: +49 (0)3731 369 474
Fax: +49 (0)3731 369 472
Copyright © 2019 Saxony Minerals & Exploration AG
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