Hydrothermal vein formation by extension-driven dewatering of the middle crust: An example from SW Germany

Fluid mixing from below in unconformity-related hydrothermal ore deposits

“…The hydrothermal veins occur within both basement rocks and the sedimentary cover. Formation ages indicate hydrothermal activity since Variscan times, peaking in the Jurassic, at which time the area was covered by a shallow sea and no significant tectonic or igneous activity is known (Staude et al, 2009, and references therein).…”

“…Geochemical evidence for fluid mixing comes from stable and radiogenic isotope signatures, mineral composition data, and fluid-inclusion compositions, including halogen ratios (Goldhaber et al, 1995;Staude et al, 2009Staude et al, , 2012Boiron et al, 2010;Wilkinson, 2010;Kendrick et al, 2011;Fusswinkel et al, 2013). Mesozoic, unconformity-related hydrothermal deposits of the Schwarzwald district in southwest Germany are representative of a large range of deposits where mixing of (1) hot, basement-derived fluids from below and (2) cooler, surface or sediment-derived fluids from above is invoked in the absence of igneous activity to drive fluid circulation (Staude et al, 2009, 2012, andreferences therein).…”

“…Mesozoic, unconformity-related hydrothermal deposits of the Schwarzwald district in southwest Germany are representative of a large range of deposits where mixing of (1) hot, basement-derived fluids from below and (2) cooler, surface or sediment-derived fluids from above is invoked in the absence of igneous activity to drive fluid circulation (Staude et al, 2009, 2012, andreferences therein). Fluid circulation driven by topography or igneous activity can be excluded for the Mesozoic deposits in the Schwarzwald (Staude et al, 2009(Staude et al, , 2012.…”

“…1A) show clear evidence for fluid mixing (Fusswinkel et al, 2013). Staude et al (2009) argued that sufficient fluid volumes to produce the deposits could have been released from below the deposits. Here we propose a new model integrating these observations and accounting for transport and mixing in a physically plausible way.…”

Negative Ce anomalies in Mn oxides: The role of Ce4+ mobility during water–mineral interaction

“…The Schwarzwald area has experienced several hydrothermal mineralization events during the Permian to Miocene (e.g., Pfaff et al, 2009;Staude et al, 2009). The main hydrothermal mineralization (primary fluorite, quartz, barite and primary carbonates) of the Clara mine is Jurassic, as demonstrated by U-Pb dating of ferberite that gave an age of 173 ± 2 Ma (Pfaff et al, 2009).…”