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The Qingyi ductile shear zone is located in the Western Shandong Province, North China Craton, and it strikes NNW-SSE with a nearly vertical mylonitic foliation and horizontal stretching lineation. This shear zone is characterized by dextral strike-slip shearing. The estimated kinematic vorticity numbers of the studied mylonites ranging from 0.79 to 0.99 indicate that the shear zone is dominated by simple shear. Microstructures, quartz fabrics and mineral assemblages reveal that this shear zone is developed in upper greenschist facies with deformation temperatures of 400–500 °C. Zircon U–Pb data of mylonites and a late-kinematic vein constrain the timing of shearing at ∼2501 Ma. Biotite 40Ar/39Ar age data of the late-kinematic vein suggest the end of late tectono-thermal events and crustal stabilisation at ∼1878 Ma. Based on the geometry, kinematics and geochronology, the Qingyi ductile shear zone is interpreted to result from microblock amalgamation and indicates a horizontal tectonic regime of the Western Shandong Province during the late Neoarchean period. • The Qingyi ductile shear zone features dextral strike-slip shearing. • Deformation temperature of the shear zone reaches 400–500 °C. • Timing of shearing deformation is ∼2501 Ma. • This shear zone indicates microblock amalgamation during the late Neoarchean. [ABSTRACT FROM AUTHOR]

The NE to ENE trending Mesozoic Xingcheng-Taili ductile shear zone of the northeastern North China Craton was shaped by three phases of deformation. Deformation phase D 1 is characterized by a steep, generally E–W striking gneissosity. It was then overprinted by deformation phase D 2 with NE-sinistral shear with K-feldspar porphyroclasts forming a subhorizontal low-angle stretching lineation on a steep foliation. During deformation phase D 3 , lateral motion accommodated by ENE sinistral strike-slip shear zones dominated. Associated fabrics developed at upper greenschist metamorphic facies conditions and show the deformation characteristics of middle- to shallow crustal levels. In some parts, the older structures have been in turn overprinted by late-stage sinistral D 3 shearing. Finite strain and kinematic vorticity in all deformed granitic rocks indicate a prolate ellipsoid (L-S tectonites) near plane strain. Simple shear-dominated general shear during D 3 deformation is probably of general significance. The quartz c-axis textures indicate prism-gliding with a dominant rhomb slip and basal slip system formed mainly at low-middle temperatures. Mineral deformation behavior, quartz c-axis textures, quartz grain size and the Kruhl thermometer demonstrate that the ductile shear zone developed under greenschist facies metamorphic conditions at deformation temperatures ranging from 400 to 500 °C. Dislocation creep is the main deformation mechanism at a shallow crustal level. Fractal analysis showed that the boundaries of recrystallized quartz grains had statistically self-similarities. Differential stresses deduced from dynamically recrystallized quartz grain size are at around 20–39 MPa, and strain rates in the order of 10 −12 to 10 −14 s −1 . This indicates deformation of granitic rocks in the Xingcheng-Taili ductile shear zone at low strain rates, which is consistent with most other ductile shear zones. Hornblende-plagioclase thermometer and white mica barometer indicate metamorphic conditions of medium pressures at around ca. 3–5 kbar and temperatures of 400–500 °C within greenschist facies conditions. The main D 3 deformation of the ENE-trending sinistral strike-slip ductile shearing is related to the roll-back of the subducting Pacific plate beneath the North China Craton. [ABSTRACT FROM AUTHOR]

Integrated geological-geophysical methods have been used to depict the geometric characteristics and kinematic evolution of the Shunbei 5 (SB5) and adjacent Shunbei1 (SB1) strike-slip faults in the central Tarim Basin, China. Geometric evidence for strike-slip faulting includes the occurrence of positive and negative flower structures in stepover zones, oblique secondary splay faults, en echelon folds, and adjacent secondary faults. The multi-humped along-strike and along-dip displacement variations of the SB5 fault provide insights into the initial segmentation, interaction and polycyclic growth of the fault zones both in plan and section views: The SB5 fault initiated as an apparent "X-type" conjugate pure shear fault system in the north and a simple shear fault system in the south respectively. At depth (mainly in Cambrian to Middle Ordovician rocks), the northern and southern parts of the SB5 fault exhibit a typical dextral strike-slip architecture consisting of multiple fault segments connected via transpressional push-up or transtensional pull-apart stepovers or bends. The southern part has a linear, narrow sinistral ridge system. At shallower depths (in Upper Ordovician to Middle Devonian rocks), the lower subvertical faults propagated upwards as en echelon normal faults in the north, and as a two-phase, partitioned system consisting of boundary grabens and en echelon normal faults that dissected the early-formed border grabens in the south. With progressive deformation, the northern and southern parts of the SB5 fault reactivated and transferred into one large, sinistral fault in Upper Devonian to Permian rocks. Four major tectonic phases matching the kinematic evolutions of regional fault systems and uplifts in the study region, have also been recognized in the Middle Ordovician to Cretaceous. The pull-apart stepover and single fault zones developed in Middle Ordovician rocks are favorable fracture-related reservoirs. • Temporospatial distributions of the SB5 fault have been interpreted. • Along-strike and along-dip displacements have been investigated to analyze fault segmentation and polycyclic evolution. • Four major strike-slip movements that occurred from the Middle Ordovician to Permian have been recognized. • The SB5 fault initiated as different strike-slip systems, then reactivated as one large fault with the same sinistral motion. [ABSTRACT FROM AUTHOR]

Baxian sag is a typical half-graben-like depression whose controlling boundary is a normal fault, the Niudong Fault. We studied the three-dimensional (3D) geometry and kinematics of this fault based on high-resolution 3D pre-stack depth migration seismic data and drilling data from the Baxian Sag. By analysing the geometries and structural deformation of the hanging wall units of the Niudong Fault, we defined the spatial variation and kinematical characteristics of the fault. The Niudong Fault is marked by a major listric normal fault that soles into a detachment surface at depth. Based on fault strikes and dips, we divided the Niudong Fault into three sections and seventeen zones. Geometrically, the Niudong Fault seems to be a single fault. While kinematically, it is not a single fault in the strict sense as various blocks of the fault have their own growth activities dominated by unidirectional and lateral growth. Map-view restoration of the Niudong Fault shows that the hanging wall was dominated by anticlockwise rotation; while cross-section restoration demonstrates that, the hanging wall was deformed by inclined shear. • High resolution 3D depth migration data are available for the study of listric fault. • 3D Geometric and kinematic models of the boundary Niudong Fault are constructed. • The Niudong Fault is not a single fault and its various sections underwent their own activities. [ABSTRACT FROM AUTHOR]