Metamorphic evolution of the northwest Himalaya, India: Pressuretemperature data, inverted metamorphism, and exhumation in the Kashmir, Himachal, and Garhwal Himalayas

Manickavasagam, R. M.; Jain, Arvind K.; Singh, Sandeep; Asokan, Ajay Dev

doi:10.1130/0-8137-2328-0.179

Cited by 25 publications

(19 citation statements)

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“…The presence of NE-dipping thrust zones along the contact between the HHC and the Lesser Himalaya (i.e. MCT zone) with top-to-SW sense of shearing is similar to the observations in the Zanskar Himalaya (Patel et al 1993), Himachal Himalaya Manickavasagam et al 1999), along the Goriganga valley, Kumaon Himalaya (Patel and Kumar, 2009) and else where in the HHC and the MCT zone (Brunel, 1986;Jain and Anand, 1988). Structural relation of shear fabrics with D 2 implies that the broad shear zone played major role in crustal thickening and rock uplift during D 2 event.…”

Section: Discussionsupporting

confidence: 83%

“…This is named as Himalayan Metamorphic Belt (HMB) (Manickavasagam et al 1999 and other references therein). Since the collision at about 55 Ma (Klootwijk et al 1992;Hodges, 2000) continued convergence has been accommodated by multiple folding and major faulting.…”

Section: Geologymentioning

confidence: 99%

“…The D 2 phase is interpreted to record the ductile stage of exhumation of the HHC, controlled by combined SWdirected thrusting along the MCT/MT and VT, and NEdirected extension along the STDS. D 2 deformation is associated with regional metamorphism between 40Ma and 15 Ma under 6-11kbar pressure and 500 -750°C temperature along with leucogranite intrusion (Seitz et al 1976;Stern et al 1989;Hubbard and Harrison 1989;Metcalfe 1993;Dezes et al 1999;Searle et al 1999;Manickavasagam et al 1999;Hodges, 2000;Bregar et al 2001;Vannay et al 2004;Yin, 2006;Jain et al 2008).…”

Section: Deformation Patternmentioning

confidence: 99%

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Geology, Structural and Exhumation History of the Higher Himalayan Crystallines in Kumaon Himalaya, India

Patel

Adlakha

Singh

et al. 2011

Journal of the Geological Society of India

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The crystallines in the Kumaon Himalaya, India are studied along Goriganga, Darma and Kaliganga valleys and found to be composed of two high-grade metamorphic gneiss sheets i.e. the Higher Himalayan Crystalline (HHC) and Lesser Himalayan Crystalline (LHC) zones. These were tectonically extruded as a consequence of the southward directed propagation of crustal deformation in the Indian plate margin. The HHC and its cover rocks i.e. the Tethyan Sedimentary Zone (TSZ) are exposed through tectonic zones within the hinterland of Kumaon Himalaya. The HHC records history of at least one episode of pre-Himalayan deformation (D 1 ), three episodes of Himalayan deformation (D 2 , D 3 , D 4 ). The rocks of the HHC in Kumaon Himalaya are thoroughly transposed by D 2 deformation into NW-SE trending S m (S 1 +S 2 ). The extent of transposition and a well-developed NE-plunging L 2 lineation indicate intense strain during D 2 throughout the studied portion of the HHC. Ductile flow continued, resulting in rotation of F 1 and F 2 folds due NE-direction and NW-SE plunging F 3 folds within the HHC. The over thickened crystalline was finally, superimposed by late-to-post collisional brittle-ductile deformation (D 4 ) and exposed the rocks to rapid erosion.Apatite Fission Track (AFT) and Zircon Fission Track (ZFT) studies from the Kumaon Himalaya suggest reactivation of the Main Central/Munsiari Thrust (MCT/MT) and Vaikrita Thrust (VT), rapid exhumation and a system that has been in topographic and exhumation steady-state since at least 4 Ma.

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Section: Discussionsupporting

confidence: 83%

Section: Geologymentioning

confidence: 99%

Section: Deformation Patternmentioning

confidence: 99%

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Geology, Structural and Exhumation History of the Higher Himalayan Crystallines in Kumaon Himalaya, India

Patel

Adlakha

Singh

et al. 2011

Journal of the Geological Society of India

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“…1). From structural pxoint of view, the Higher Himalaya has been referred as the 'Higher Himalayan Shear Zone' (HHSZ) by the Roorkee school (Jain and Anand 1988;Jain and Manickavasagam 1993;Manickavasagam et al 1999;Jain et al 2000Jain et al , 2002Jain et al , 2005aMukherjee 2007Mukherjee , 2008; Mukherjee and Koyi 2009b) and recently as an 'orogenic channel' by the tectonic modelers at Dalhousie (e.g. Beaumont et al 2001Beaumont et al , 2004Jamieson et al 2004).…”

Section: Introductionmentioning

confidence: 98%

Higher Himalayan Shear Zone, Sutlej section: structural geology and extrusion mechanism by various combinations of simple shear, pure shear and channel flow in shifting modes

Mukherjee

Koyi

2009

Int J Earth Sci (Geol Rundsch)

143

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The Higher Himalayan Shear Zone (HHSZ) in the Sutlej section reveals (1) top-to-SW ductile shearing, (2) top-to-NE ductile shearing in the upper-and the lower strands of the South Tibetan Detachment System (STDS U , STDS L ), and (3) top-to-SW brittle shearing corroborated by trapezoid-shaped minerals in micro-scale. In the proposed extrusion model of the HHSZ, the E 1 -phase during 25-19 Ma is marked by simple shearing of the upper subchannel defined by the upper strand of the Main Central Thrust (MCT U ) and the top of STDS U as the lower-and the upper boundaries, respectively. Subsequently, the E 2a -pulse during 15-14 Ma was characterized by simple shear, pure shear, and channel flow of the entire HHSZ. Finally, the E 2b -pulse during 14-12 Ma observed simple shearing and channel flow of the lower sub-channel defined by the lower strand of the Main Central Thrust (MCT L ) and the top of the STDS L as the lower-and the upper boundaries, respectively. The model explains the constraints of thicknesses of the STDS U and the STDS L along with spatially variable extrusion rate and the inverted metamorphism of the HHSZ. The model predicts (1) shear strain after ductile extrusion to be maximum at the boundaries of the HHSZ, which crudely matches with the existing data. The other speculations that cannot be checked are (2) uniform shear strain from the MCT U to the top of the HHSZ in the E 1 -phase; (3) fastest rates of extrusion of the lower boundaries of the STDS U and the STDS L during the E 2a -and E 2b -pulses, respectively; and (4) variable thickness of the STDS L and rare absence of the STDS U . Non-parabolic shear fabrics of the HHSZ possibly indicate heterogeneous strain. The top-to-SW brittle shearing around 12 Ma augmented the ductile extruded rocks to arrive a shallower depth. The brittle-ductile extension leading to boudinage possibly did not enhance the extrusion.

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“…MCT, a major shear zone separating the Higher Himalayan Crystallines from the Lesser Himalayan Series, is a major thrust fault that has contributed to the formation of the Himalaya [3]. MCT is thought to be an early Paleozoic Suture Zone [4][5][6]. It extends for nearly 2500 km along strike and has been the site of at least 120 -140 km and perhaps more than 600 km of displacement [7][8][9] from its formational site.…”

Section: Introductionmentioning

confidence: 99%

Clusters of Moderate Size Earthquakes along Main Central Thrust (MCT) in Himalaya

Mukhopadhyay¹

2011

IJG

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The Main Central Thrust (MCT) in Himalaya is seismically active in segments. In recent times, strain release within these active segments produce five spatial clusters (A to E; Figure 1). The seismicity within the cluster zones occurs in two depth bands; corresponding to the base of upper and lower crust. Depth sections across the clusters illustrate gently dipping subducted Indian Plate, overriding Tibetan Plate and compressed Sedimentary Wedge in between, with mid crustal ramping of MCT. Several presumptions / hypotheses have been put forward to decipher the causes of clustering along MCT. These are segmental activation of MCT, cross fault interactions, zones of arc parallel and arc perpendicular compressions, pore pressure perturbations, low heat flow zones etc. But these hypotheses need to be evaluated in the future after more ground level data are available. The maximum size of seismic threat that MCT can produce is inferred to be around Mw 7.0 in those clusters.

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Metamorphic evolution of the northwest Himalaya, India: Pressuretemperature data, inverted metamorphism, and exhumation in the Kashmir, Himachal, and Garhwal Himalayas

Cited by 25 publications

References 0 publications

Geology, Structural and Exhumation History of the Higher Himalayan Crystallines in Kumaon Himalaya, India

Geology, Structural and Exhumation History of the Higher Himalayan Crystallines in Kumaon Himalaya, India

Higher Himalayan Shear Zone, Sutlej section: structural geology and extrusion mechanism by various combinations of simple shear, pure shear and channel flow in shifting modes

Clusters of Moderate Size Earthquakes along Main Central Thrust (MCT) in Himalaya

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