The manuscript re-analyses seismic data from the UPPLAND profile in the Fennoscandian Shield, focusing on P- and S-wave velocity models. Significant differences between prior and present models emerge in the lower crust and mantle and in the Moho depth. The new model suggests ca. 7.1 km s^-1 in the lower crust and 8.05 km s^-1 in the upper mantle, with Moho at 43–50 km. Two tectonic interpretations are proposed to explain these findings, emphasising the complexities of seismic data interpretation.

We address the transition between the Paleozoic Variscan and Alpine Mesozoic–Cenozoic cycles using tectono-stratigraphy and thermochronology. This transition unfolds through a multi-phase rifting history. An initial rifting stage occurred in the early Permian, followed in the early–middle Permian by a phase of transcurrent tectonics. This was succeeded by a period of erosion/non-deposition in the middle Permian. Crustal stretching in the Middle Triassic marked the onset of the Alpine cycle.