Tectonic controls on lithium deposits in the Erzgebirge / Krušné hory region: Regional scale reconstruction of structural controls on late-Variscan mineralization

The Eastern Erzgebirge (Germany) and Krušné hory (Czech Republic / Czechia) region hosts prolific Li-(Sn W) deposits, all linked to late-stage magma evolution and magmatic-hydrothermal alteration within a Caldera collapse system. Whereas the geochemical controls are relatively well understood, tectonic controls on magma emplacement are not. Here, we aim to explain the tectonic controls on trans-crustal caldera-forming magmatic systems, and link these to more local controls on fertile magmatism. This is achieved by compiling and reviewing available geological, geochronological, geophysical, and structural data, and integrating them to derive a framework for late- to post-Variscan tectonics and magmatism. Specifically, we link the main faults in the vicinity of the Altenberg-Teplice and Tharandt calderas with the western middle Pennsylvanian (~314–312 Ma) Bohemian basin system, to propose a major transtensional linkage structure between the Elbe Shear Zone and Pfahl or Danube Shear Zones. We propose that these transtensional pull-apart basins and dextral strike-slip fault systems do not only localize crustal-scale magmatic systems and associated calderas, but also exert a more local control on intra-caldera intrusive stocks that are host to greisen-type Li-(Sn W) ore deposits in the Eastern Erzgebirge / Krušné hory region.