Prabornaz Mine (Praborna Mine), Saint-Marcel, Aosta Valley, Italy
|Latitude & Longitude (WGS84):||45° 40' 45'' North , 7° 26' 57'' East|
|Latitude & Longitude (decimal):||45.67944,7.44944|
|Other regions containing this locality:||The Alps, Europe|
|Köppen climate type:||ET : Tundra|
|Name(s) in local language(s):||Miniera di Prabornaz, Saint-Marcel, Valle d'Aosta, Italia|
The manganese concentrations of Prabornaz are restricted to a 4x8 m thick quartzite unit of diverse lithologies which represent the basal part of the sedimentary cover of an ophiolite suite. Together they constituted the Piedmont Nappe which was metamorphosed up to the eclogite facies in Cretaceous times and was retrogressed in the early Tertiary.
The quartzite unit is composed of a succession of siliceous levels characterized by Mn-bearing minerals reflecting differences in chemical composition and oxygen fugacity inherited from the original sediments. The parageneses evolved during the polyphasic Alpine metamorphism passing through a pre-eclogite blue-schist facies event, the main eclogite facies event, and the several post-eclogite stages terminating in the greenschist facies.
These Mn concentrations were subsequently penetrated by several networks of cross-cutting veins and late fractures which were responsible for the mobilization of certain elements, in particular, K, Sr, and Ba.
65 valid minerals. 4 (TL) - type locality of valid minerals. 2 (FRL) - first recorded locality of unapproved mineral/variety/etc.
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
252.17 - 358.9 Ma
|Paleozoic volcanic and intrusive rocks|
Age: Paleozoic (252.17 - 358.9 Ma)
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529. 
252.17 - 541 Ma
Age: Paleozoic (252.17 - 541 Ma)
Description: medium grade metamorphic
Reference: Asch, K. The 1:5M International Geological Map of Europe and Adjacent Areas: Development and Implementation of a GIS-enabled Concept. Geologisches Jahrbuch, SA 3.