Kinematics of Tertiary deformation in the basement-involved fold-thrust complex, western Nordenskiøld Land, Svalbard: tectonic implications based on fault-slip data analysis

摘要: Abstract Kinematic analysis based on the interpretation of small-scale fault and fold data supports a kinematic evolution history involving heterogeneous crustal shortening uplift, subsequent extension (collapse) for major, west coast fold-thrust complex in western Nordenskiold Land, Svalbard. This deformation can be divided into three main events. Stage 1 represents an early, distinctive, NNE-SSW-oriented contractional episode that generated layer parallel low-angle thrusts internal folds. structures (population 1) are arranged apparent en-echelon geometry oblique direction relative to major NNE-SSW-trending stage 2 affinity. include ENE-verging chevron folds steeply WSW-dipping duplexes, evolved during progressive WSW-ENE-oriented episode. Initial (pre-fold) stratal (stage 2a) was followed by continuous buildup general thickening (syn-fold, 2b), until supercritical height/thickness reached (post-fold, 2c). At this change stress field caused failure complex, continued NE-SW-directed accommodated as vertical strike-slip faults Late W-E-to WSW-ENE-directed extension, 3 episode, probably related collapse overthickened complex. The detailed reconstruction events Land initial breakup Greenland-Svalbard area Early Paleocene (?) times dextral, NNE-SSW-directed transpression 1). deformational 2), mid-Paleocene Eocene age, characterized decoupled where broad zones convergent strain were linked narrow zones. partitioning is considered have begun when Hornsund Fault Zone widened reactivated basin-bounding Carboniferous St. Jonsfjorden Trough. latest 3) likely may ascribed extensional hinterland Spitsbergen orogenic wedge within regional, dextral transpressive setting.