Thermal evolution in the exhumed basement of a stratovolcano: case study of the Miocene Mátra Volcano, Pannonian Basin

Abstract

The thermal influence of a Miocene stratovolcano (Mátra Volcano) on its basement was studied by apatite and zircon (U–Th)/He thermochronometry. The pre-Miocene substratum of the volcano contains Mesozoic sedimentary units in addition to the nearby exhumed igneous Recsk Complex. The Oligocene emplacement age of the Recsk Complex is constrained by zircon U–Pb geochronology to be 29.6 Ma, which serves as a benchmark for the beginning of its thermal history. All measured apatite (U–Th)/He ages (19.9–5.9 Ma) and most of the zircon (U–Th)/He ages (26.2–17.7 Ma) are considerably younger than the emplacement age of the Oligocene Recsk Complex, implying thermal overprinting by the adjacent Miocene Mátra Volcano. The apatite and zircon He ages of the Oligocene complex increase from south to north, providing clear evidence of a northwards-weakening thermal overprint. The post-Oligocene thermal history of the basement was reconstructed via one-dimensional subsidence/thermal modelling. According to zircon He modelling, the thickness of the covering units above the Recsk Complex was estimated to be 1000–1500 m and the heat flux was c. 200 mW m −2 during the Miocene volcanism. Thermal modelling based on apatite He data suggests that the Miocene volcanism was followed by intensive erosion and the exposure of the Recsk Complex by the Late Miocene. Supplementary material: The locality, petrography and age yield of the dated samples of the Recsk Igneous Complex and details of the laser ablation inductively coupled plasma mass spectrometry dating of zircons from the Recsk Complex are available at: https://doi.org/10.6084/m9.figshare.c.4127444