Rotation of long tectonic clasts in transpressional shear zones

Mid‐Neoproterozoic Tectonics of Northwestern India: Evidence of Stitching Pluton along 810 Ma Phulad Shear Zone

“…Asymmetric mesoscopic structures in XZ section suggest top‐to‐the‐NNW reverse sense of movement (Figure c). This movement direction in PSZ is parallel to the stretching lineation and perpendicular to the vorticity axis (Figure d) (Ghosh et al, ; Sengupta & Ghosh, ; Chatterjee et al, ). Because of this oblique reverse slip movement in the shear zone, there is a component of sinistral slip movement on subhorizontal section (Figures d and e).…”

“…In northwestern India, the Phulad Shear Zone (PSZ, henceforth) demarcates the boundary between South Delhi Fold Belt (SDFB) to the east and Marwar craton to the west (Figure a) (Chatterjee et al, ; Ghosh et al, , ; Golani et al, ; Gupta et al, ; Heron, ; Roy & Jakhar, ; Sen, ; Sengupta & Ghosh, , ; Sinha Roy, ; Sinha‐Roy et al, , , ; Sugden et al, ; Sychanthavong & Desai, ; Tewari et al, ; Volpe & Macdougall, ). The PSZ is described as a terrane boundary shear zone (Sinha Roy, ) along which the Greater India landmass accreted with the Marwar Craton at ~810 Ma (Chatterjee et al, ).…”

“…The PSZ is described as a terrane boundary shear zone (Sinha Roy, ) along which the Greater India landmass accreted with the Marwar Craton at ~810 Ma (Chatterjee et al, ). The PSZ is characterized by NE‐SW trend and steep easterly dipping mylonitic foliation that runs for several kilometers (Chatterjee et al, ; Ghosh et al, , ; Golani et al, ; Gupta et al, ; Heron, ; Roy & Jakhar, ; Sen, ; Sengupta & Ghosh, , ; Sinha Roy, ; Sinha‐Roy et al, ; Sinha‐Roy et al, ; Sychanthavong & Desai, ). Structural studies of PSZ indicate that deformation in the shear zone is transpressional with a reverse sense of movement (Ghosh et al, , ; Sengupta & Ghosh, , ).…”

Paleoproterozoic/Mesoproterozoic tectonism in the northern fringe of the Western Dharwar Craton (India): Its relevance to Gondwanaland and Columbia supercontinent reconstructions

“…Progressive southward increase in deformation strain in the footwall schists straddled by the two major dislocation zones (NSZ and SSZ) is manifested by coaxial refolding of steeply plunging south‐vergent reclined folds in the footwall schists with axes parallel to the down dip stretching lineation, tightening of refolded folds, and progressive obliteration of pre‐existing tectonic fabrics. The common occurrence of reclined folds with fold axis parallel to steeply plunging stretching lineation in this crustal domain is consistent with strike slip shearing, e.g., vorticity vector subparallel to stretching lineation [ Ghosh et al ., , ]. By contrast, the occurrence of sheath folds with tubular extensions subparallel to the steeply plunging mineral lineation in and neighboring the NSZ, and the SSZ demarcating the cratonic fringe, is best explained by dominant dip‐slip movement and subhorizontal vorticity vector [ Ghosh et al ., ].…”

“…The common occurrence of reclined folds with fold axis parallel to steeply plunging stretching lineation in this crustal domain is consistent with strike slip shearing, e.g., vorticity vector subparallel to stretching lineation [ Ghosh et al ., , ]. By contrast, the occurrence of sheath folds with tubular extensions subparallel to the steeply plunging mineral lineation in and neighboring the NSZ, and the SSZ demarcating the cratonic fringe, is best explained by dominant dip‐slip movement and subhorizontal vorticity vector [ Ghosh et al ., ]. The kinematic considerations seem to suggest that the spatial variations in south‐vergent fold structure in the Pernem‐Phonda corridor is the result of transpressional ductile deformation, with dip‐slip movement induced by top‐to‐the‐south translation of the hanging wall schists over the cratonic foreland localized along the two major dislocation zones, e.g., the NSZ and the SSZ.…”