Application of a critical wedge taper model to the Tertiary transpressional fold-thrust belt on Spitsbergen, Svalbard

摘要: The Tertiary opening of the North Atlantic Ocean involved major and long-lived overall dextral transpression between Svalbard Greenland plates. On Spitsbergen, this tectonic event is manifest as a 100–200-km-wide contractional fold-thrust belt in form an east-pinching prism. This can be subdivided into (1) western, basement-involved hinterland province that reveals more complex deformation, including thrust, transcurrent, normal faulting, (2) eastern thin-skinned with structures oriented subparallel (north-northwest–south-southeast) to transform plate boundary. time-space distribution interaction different structural styles deformation evident on Spitsbergen support model linked, long-term short-term (episodic) dynamic growth composite transcurrent wedge. narrow, high-taper (critical-supercritical) wedge occurred during northward-directed crustal shortening (stage 1) oblique, setting. Crustal thickening thrust uplift basin inversion strike-slip duplexing main (stages 2 3) created unstable, supercritical basement cover rocks hinterland. At same time, broader homogeneous frontal part developed eastward by in-sequence imbrication order reduce taper angle. Local erosion lateral extrusion 3 4) modified oversteepened critical Continued activity caused renewed internal wedge, where was accommodated tear faulting out-of-sequence thrusting 4). Adjustment toward stable geometry included local extension 5) sedimentation. In transpressional belt, out-of-plane (orogen oblique parallel) transport may cause subcritical tapers. Hinterland geometries could trigger adjustments decoupled situation, and/or orogen or parallel motions coupled situation. Changing kinematics thus expected along strike such orogen.