Abstract A detailed analysis of the Late Miocene Mandach Thrust, a key tectonic structure of the easternmost Jura Mountains (northern Alpine foreland), is presented providing insights into the modes of along-strike structural cover–basement interactions in a classical foreland setting. Our study builds on the construction, restoration and forward modelling of eight closely spaced cross-sections constrained by depth-migrated 2D seismics and geological maps. The results indicate predominantly thin-skinned thrust tectonics without significant inversion of underlying basement structures. However, inherited pre-thrusting normal faults exerted a strong control on the observed thrusting style, changing along-strike from a comparatively simple geometry to a complex, partly overthrust, partly reactivated normal fault. The observed variations relate to changes in the relief of the mechanical basement and the characteristics of pre-thrusting normal faults. The thrust's complexity is further increased by the local activation of secondary detachment horizons and possibly along-strike sedimentary facies changes within the thrust-faulted sedimentary sequence. The variations in thrusting style go along with subtle changes in shortening that may point towards as yet undetected transfer structures. As such, our structural analysis of the Mandach Thrust provides an improved understanding of the fault's kinematics and serves to highlight existing exploration uncertainties.

Abstract In the early 1830s Charles Lyell was convinced that much of western Europe had been submerged during the Pleistocene by cold seas strewn with icebergs; the relicts of whose loads of rock and mud occurred on land as boulder clay and erratic blocks. Swiss scientist Louis Agassiz disagreed, considering in 1837 that these were the products of deposition by a great ice sheet. Archibald Geikie realized by 1863 that Lyell was wrong. Mountain glaciers had carved the topography of Scotland and other parts of the UK, feeding an ice sheet that left glacial erratics behind when it melted away. He hoped, in vain, to change Lyell’s mind. Archibald Geikie’s mantle passed to his brother James, who compiled evidence from around the world to demonstrate the correctness of his brother’s thesis. It was published in 1874 just before Lyell died still arguing for the correctness of his iceberg theory, which gave us the word ‘drift’ for the unconsolidated deposits mantling the UK. Even so, by then Lyell had gone some way – no doubt partly influenced by the Geikies – to accepting that in certain instances glacial action had, indeed, moved large erratic blocks – locally even uphill, as in the Jura.