Synorogenic extension: Quantitative constraints on the age and displacement of the Zanskar shear zone (northwest Himalaya)

Dèzes, P.; Vannay, Jean-Claude; Steck, A.; Bussy, F.

doi:10.1130/0016-7606(1999)111<0364:seqcot>2.3.co;2

Cited by 151 publications

(189 citation statements)

References 39 publications

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“…Based on structural and/or geochronological evidence, extensional motion in the Higher Himalayas has been considered coeval with thrusting at lower topographic levels (Royden and Burchfi el 1987, Inger 1998, Dézes et al 1999). In the Caledonides, Harz et al (2001) proposed the same structural relationship.…”

Section: Introductionmentioning

confidence: 99%

Kinematics and geometry of structures in the southern limb of the Paraíba do Sul divergent structural fan, SE Brazil: a true transtensional shear

Dehler

Machado

Dehler

et al. 2006

An. Acad. Bras. Ciênc.

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Shear zones geometry in the Paraíba do Sul belt, southeastern Brazil, delineates a NE-trending fan-like structure. Shear zones dip towards SE in the northern limb, and towards NW in the southern one. This geometry has been interpreted either due to transpression or to late folding of flat-lying thrust surfaces. Stretching lineation plunges to ENE-ESE in the northern limb and towards NNE-NE in the southern one. Structural data in the southern limb of the divergent fan suggest a two stage kinematic evolution in high-temperature conditions: an earlier stage with top-to-SSW/SW sinistral thrusting and orogenic-parallel tangential motion, and a later stage with top-down to NNE/NE transtensional deformation. We propose a heterogeneous deformation model to explain the observed shear reversal, and suggest that the imposed transpressional displacement gradient may change during progressive deformation due to transient rheological inhomogeneities in bulk pure shear strain. In the earlier stage, the partially molten material could easily accommodate the imposed strain rates, giving rise fi rstly to the SW-directed shearing. As the thermal disturbance tended to vanish and the convergence increased, the NNE-directed transtensional shearing developed. We propose that the transtensional deformation characterized in this paper could be related to extrusion processes during regional transpressional strain.

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Section: Introductionmentioning

confidence: 99%

Kinematics and geometry of structures in the southern limb of the Paraíba do Sul divergent structural fan, SE Brazil: a true transtensional shear

Dehler

Machado

Dehler

et al. 2006

An. Acad. Bras. Ciênc.

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“…This migmatitic core is symmetrically surrounded by rocks of the sillimanite, kyanite ± staurolite, garnet, biotite, and chlorite mineral zones. The structural and metamorphic data from the Miyar-Gianbul Valley section reveal that the tectono-metamorphic evolution of the HHCZ in SE Zanskar is associated with a polyphase tectonic history involving converging nappe structures superimposed by opposite-directed extensional structures (Dèzes et al 1999, Steck et al1999, Robyr et al 2002. The first tectonic event corresponds to an early phase of crustal thickening related to NE-directed movements.…”

Section: High-grade Metamorphic Rocks Of the High Himalayanmentioning

confidence: 99%

Timing of synconvergent extension in NW Himalaya: New geochronological constraints from the Gianbul dome (SE Zanskar)

Robyr

Mattinson

Hacker

2008

Himalayan Journal of Sciences

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“…At this time, the regime of N-S extension was dominant. When the India-Asia convergence speeded up, the Himalaya experienced a rapid deformation, resulting in Figure 8 Statistical diagram of the U-Pb/U-(Th)-Pb ages of leucogranites and 40 Ar/ 39 Ar ages of leucogranites and metasedimentary rocks in Himalayan orogen (data from [1,[4][5][6][7][8][9][10][11][12][13][15][16][17][18][22][23][24]30,). the thrusting and shorting.…”

Section: Geodynamic Implications On the Transformation Of Tectonic Rementioning

confidence: 99%

“…This confirms the view that NSTR is probably the result of N-S contraction [29] and provides unequivocal evidence for the transformation of tectonic regime. In order to accurately constrain the time of the transformation of tectonic regime from N-S extension to N-S contraction, we summarize and analyze the ages of STDS and NSTRs in Gyirong and other areas in Himalayan orogen ( Figure 7) [4][5][6][7][8][9][10][12][13][14][15][16][17]22,28,[30][31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. The result shows that the STDS was active from ca.…”

Section: Middle-miocene Transformation Of Tectonic Regime In Himalayamentioning

confidence: 99%

“…(2) After early Oligocene, the tectonic regime transformed from N-S contraction to N-S extension. Between late Oligocene and early Miocene (28.4-16.2 Ma), the northern Himalayas experienced widespread extension, resulting in large scale extensional tectonics, such as the north-dipping STDS [4][5][6][7][8][9][10][11][12][13][14][15][16]. (3) In middleMiocene (~13 Ma), the tectonic regime shifted to E-W extension [17,18], which formed the NSTR cutting the STDS, such as Yadong-Gulu rift, Nima-Dingri rift and XainzaDinggye rift.…”

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Middle-Miocene transformation of tectonic regime in the Himalayan orogen

et al. 2012

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Understanding the multiple tectonic transformations during the Himalayan orogeny is significant in evaluating the evolution of Himalayan orogen. In the Gyirong area in south Tibet, deformed leucogranitic veins in the biotite-plagioclase gneisses of Greater Himalayan crystalline complex (GHC) constitute south-vergent asymmetric folds. The reconstruction of the veins shows that they experienced two generations of deformation under different tectonic regimes: an earlier top-to-north extension and a later top-to-south thrusting, implying a tectonic transformation from N-S extension to N-S shortening. Zircons LA-ICP-MS U-Pb dating of the leucogranite shows that it was emplaced during 21.03-18.7 Ma. The data suggest that the tectonic transformation occurred after 18.7 Ma. The chronological data of South Tibet detachment system (STDS) and North-South trending rift (NSTR) from Gyirong and other areas indicate that the Himalayan orogeny was in a period of tectonic transformation from N-S extension to N-S shortening during 19-13 Ma. The transformation of tectonic regime was probably controlled by the India-Asia convergence rate. An increase in the convergence rate resulted in N-S shortening of the orogen, thrusting and folding, with coeval formation of the NSTR in Tibet. A decrease in the convergence rate led to N-S extension and reactivation of the STDS.

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Synorogenic extension: Quantitative constraints on the age and displacement of the Zanskar shear zone (northwest Himalaya)

Cited by 151 publications

References 39 publications

Kinematics and geometry of structures in the southern limb of the Paraíba do Sul divergent structural fan, SE Brazil: a true transtensional shear

Kinematics and geometry of structures in the southern limb of the Paraíba do Sul divergent structural fan, SE Brazil: a true transtensional shear

Timing of synconvergent extension in NW Himalaya: New geochronological constraints from the Gianbul dome (SE Zanskar)

Middle-Miocene transformation of tectonic regime in the Himalayan orogen

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