Metallogeny and petrogenesis of lamprophyres in the mid-european variscides / Металлогения и петрогенез лампрофиров в среднеевропейских варисцид

Post-Collisional Magmatism and Its Relationship to Late-Variscan Ore Forming Processes in the Erzgebirge (Bohemian Massif)

Постколлизионный магматизм и его связь с поздневарисканскими рудообразующими процессами в Эрцгебирге (Богемский массив)

The main goal of this contribution is to document the possible importance of post-collisional lamprophyre intrusions for late-Variscan ore mineralization in the Erzgebirge (Germany and Czech Republic). Located at the northwestern border of the Bohemian massif in the Internal Variscides, the Erzgebirge is one of the most important silver, tin, tungsten, uranium, lead, zinc, copper, indium, bismuth, cobalt, and fluorite ore deposit provinces in Europe with a mining history of more than 800 years. Because of the close spatial association between late-Variscan ore mineralization and Permo-Carboniferous lamprophyric and rhyolitic intrusions the Erzgebirge is one of the key localities to study the genetic relationship of epigenetic Sn-W-Mo, Ag-base metal, and U deposits with post-collisional, mantle derived magmatic pulses.
Lamprophyres and granitic/rhyolitic rocks from various ore districts of the Erzgebirge were collected from underground and surface outcrops, and drill cores. Shoshonitic/ultrapotassic mafic volcanics were collected in surface outcrops of the Sub-Erzgebirge basin. Data were obtained for petrographic-mineralogical studies (n = 117), major, trace and rare earth element analyses (n = 115), Nd-Nd (n = 42), Sr-Sr (n = 42), and Pb-Pb isotope analyses (n = 65). Representative samples were dated using K/Ar (n = 8), Ar/Ar (n = 7), Pb-Pb single zircon evaporation (n = 4), and U-Pb SHRIMP methods (n = 2). Additionally, felsic (sub)volcanic rocks of the Erzgebirge and the Sub-Erzgebirge basin were analyzed by geochemical (n = 21), and radiogenic isotope methods (n = 17).Most lamprophyric dikes (thickness from 0.5 - 30 m) occur in areas of crosscutting deep fault zones which also act as conduits for post-collisional rhyolitic intrusions and host postmagmatic Sn-W-Mo, Ag-base metal, and U deposits. The lamprophyres in the Erzgebirge have been divided into three main groups (LD1 - LD3) using criteria of petrography and geochemistry, and relatively age relationships to late-Variscan volcano-plutonic activity and mineralization phase<...>