Late Cretaceous exhumation and uplift of the Harz Mountains, Germany: a multi-method thermochronological approach

Abstract

The Harz Mountains represent one of the most prominent surface expressions of Late Cretaceous intraplate shortening in Central Europe. We present a comprehensive low-temperature thermochronological data set (zircon and apatite, fission track and [U–Th]/He) covering the exhumed Paleozoic basement of the Harz Mountains and the adjacent Kyffhauser block, as well as Lower Triassic sedimentary rocks of the western and southern rim of the Harz Mountains. Integration of results with sedimentological data from the syntectonic Late Cretaceous Subhercynian Basin allows for a detailed reconstruction of the timing of uplift and erosion of the Harz Mountains. The data reveal that (i) tectonic reorganization and initial exhumation started at around 90 Ma, (ii) uplift and emergence caused erosion of the Mesozoic sedimentary cover between 86–85 Ma and 83–82 Ma, and (iii) erosion of at least 3–4 km of underlying Paleozoic rocks followed and continued into the Paleogene. The thickness of removed overburden amounts to at least 6 km, and most erosion occurred in Santonian to Campanian time at minimum rates of ~ 0.5 km/Myr. The southwestern rim of the Harz has exhumed slower over a longer period of time, and may record a phase of Late Cretaceous, syntectonic sediment accumulation.