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

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 as well as 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 overprint by the adjacent Miocene Mátra Volcano. The apatite and zircon He ages of the Oligocene complex increase from S to N, providing clear evidence of a northward 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 31 above the Recsk Complex was estimated at 1000–1500 m and the heat flux was around 200 mW/m² 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 Late Miocene.