Quantifying Early Miocene in-sequence and out-of-sequence thrusting at the Alpine-Carpathian junction

Abstract

A detailed reconstruction of late Oligocene and Early Miocene thrusting at the leading edge of the East Alpine fold-thrust belt is achieved from well data, seismic, and interpretative cross sections. Data are used for constraining the paleogeographic positions of the Alpine thrusts, quantifying in-sequence/out-of-sequence thrust distances, assessing the timing of thrust propagation from structurally higher units into more external ones, and estimating thrust velocities. Results are depicted in five palinspastic maps for time slices betweeñ 26 Ma and~16 Ma. The termination of foreland-propagating thrusting at the Alpine front is apparently controlled by the subcrop topography of the European basement, which includes a major recess in the east leading to a diachronic along-strike termination of foreland-propagating thrusting with younger thrust ages and higher in-sequence thrust distances in the east. Early locking of foreland-propagating thrusting in the west causes prominent out-of-sequence thrusts which add to the in-sequence thrust distances there. Continuing consecutive detachment of foreland units in the east occurs at rather fast propagation velocities with time intervals between foreland-thrust-propagations ranging between 0.1 and 0.7 Ma. The resulting increase of in-sequence thrust distances from west to east is balanced by out-of-sequence thrusts in the west. The total amount of late Oligocene to Early Miocene thrusting is quantified with a minimum of 51 km. Average thrust velocities range between 4.6 and 5.2 mm/yr. This rate refers to the movement of the basal thrust at the leading edge of the fold-thrust belt, which occurs contemporaneous with the eastward lateral extrusion of the Eastern Alps in the hinterland.

Cooling and Vertical Motions of Crustal Wedges Prior to, During, and After Lateral Extrusion in the Eastern Alps: New Field Kinematic and Fission Track Data from the Mur‐Mürz Fault System

“…Although similar early Miocene shortening directions were inferred along the conjugate Pöls‐Lavanttal strike‐slip fault (Pischinger et al, ), we propose that our D1 kinematics are early Miocene or older but are not directly linked to lateral extrusion of the Styrian block for the reason given above. However, our D1 shortening direction is consistent with those related to the pre‐extrusion piggy‐back basin phase of the Vienna basin during the early Miocene (Ottnangian and early Karpatian) and out‐of‐sequence thrusting within the Northern Calcareous Alps (see Figure , Beidinger & Decker, ; Decker et al, ; Fodor, ; Hölzel et al, ).…”

Polyphase tectonic subsidence evolution of the Vienna Basin inferred from quantitative subsidence analysis of the northern and central parts

“…The NE-SW trending strike, however, is not genetically related to the Láb-Leitha strike-slip fault system. This can be related to an apparent counterclockwise rotation of the Alpine thrust front between the Eggenburgian and the Karpatian (Beidinger and Decker 2014), resulted from the eastward increase of the cumulative insequence thrust distance.…”

Geometry, amount, and sequence of thrusting in the Subalpine Molasse of western Austria and southern Germany, European Alps

“…Constraints on deformation timing are deduced from the sedimentary evolution of the foreland deposits. Based on this evidence, we reconstruct the tectonic history of the frontal part of Alpine orogenic wedge from the Oligocene to the Miocene and discuss the interaction of processes in external and internal parts of the Alpine orogenic wedge [e.g., Beidinger and Decker , ; Frisch et al ., ; Rosenberg and Berger , ; Schmid et al ., , ].…”