Role of initial basin width in partitioning total shortening in the Lesser Himalayan fold-thrust belt: Insights from regional balanced cross-sections

Bhattacharyya, Kathakali; Ahmed, Farzan

doi:10.1016/j.jseaes.2015.11.012

Cited by 19 publications

(16 citation statements)

References 39 publications

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“…Sustained lower convergence rates would be associated with a westward decrease of the total amount of shortening. Although currently available data do not readily support the interpretation of a decrease of total shortening with increasing obliquity of the convergence direction (e.g., Bhattacharyya & Ahmed, ; DeCelles et al, ), we note that these estimates are notoriously difficult to obtain and fraught with uncertainties.…”

Section: Discussioncontrasting

confidence: 74%

Segmentation of the Main Himalayan Thrust Revealed by Low‐Temperature Thermochronometry in the Western Indian Himalaya

et al. 2018

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Despite remarkable tectonostratigraphic similarities along the Himalayan arc, pronounced topographic and exhumational variability exists in different morphotectonic segments. The processes responsible for this segmentation are debated. Of particular interest is a 30-to 40-km-wide orogen-parallel belt of rapid exhumation that extends from central Nepal to the western Himalaya and its possible linkage to a midcrustal ramp in the basal décollement, and the related growth of Lesser Himalayan duplex structures.Here we present 26 new apatite fission track cooling ages from the Beas-Lahul region, at the transition from the Central to the Western Himalaya (~77°-78°E) to investigate segmentation in the Himalayan arc from a thermochronologic perspective. Together with previously published data from this part of the orogen, we document significant lateral changes in exhumation between the Dhauladar Range to the west, the Beas-Lahul region, and the Sutlej area to the east of the study area. In contrast to the Himalayan front farther east, exhumation in the far western sectors is focused at the frontal parts of the mountain range and associated with the hanging wall of the Main Boundary Thrust fault ramp. Our results allow us to spatially correlate the termination of the rapid exhumation belt with a midcrustal ramp to the west. We suggest that a plunging anticline at the northwestern edge of the Larji-Kullu-Rampur window represents the termination of the Central Himalayan segment, which is related to the evolution of the Lesser Himalayan duplex.

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Section: Discussioncontrasting

confidence: 74%

Segmentation of the Main Himalayan Thrust Revealed by Low‐Temperature Thermochronometry in the Western Indian Himalaya

et al. 2018

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“…Addressing the first-order lateral variation of shortening estimates along the Himalayan FTB from available datasets from various transects of the mountain belt has been the focus of some recent studies (Mitra et al, 2010, Long et al, 2011, Bhattacharyya et al, 2013b. To arrive at the total minimum shortening in the Darjeeling-Sikkim Himalayan FTB up to the Indus suture, we have incorporated the shortening estimates from the Tethyan sequence (~139 km) from a transect lying northwest of the Sikkim Himalaya (Ratschbacher et al, 1994,Searle et al, 1997 to the results from this study; we arrive at a total shortening estimate of ~589 km in this region.…”

Section: Shortening Estimate From Darjeeling-sikkim Himalaya and The mentioning

confidence: 99%

Geometry and kinematics of the Darjeeling–Sikkim Himalaya, India: Implications for the evolution of the Himalayan fold-thrust belt

Bhattacharyya

Mitra

Kwon

2015

Journal of Asian Earth Sciences

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“…Since then, it has been a topic of continuous study by the Geological Survey of India as well as academic researchers (see for example, Ray, ; Ghosh, ; Acharya, ; Acharya & Ray, ; Ghosh & Singh, ; Gangopadhyay, ; Sinha‐Roy, ) which have attempted to clarify the stratigraphic and structural relationships in the area. Interest in the structural, petrological, geophysical and geochronological evolution of the Sikkim Himalaya continues to the present day with an increase in the number of publications in the last few years ( Structure and regional patterns : Mukul, ; Searle & Szulc, ; Bhattacharyya & Mitra, , ; Matin & Mazumdar, ; Mitra et al ., ; Bose et al ., ; Bhattacharyya et al ., ,b; Bhattacharyya & Ahmed, ; Geophysics: Kayal, ; De & Kayal, ; Nath, ; Tiwari et al ., ; Singh et al ., ; Patro & Harinarayana, ; Hazarika et al ., ; Acton et al ., ; Mukhopadhyay, ; Hazarika et al ., ; Sharma et al ., ; Petrology and Geochemistry, including isotopic dating and thermochronometry: Banerjee & Bhattacharya, ; Lal et al ., ; Mohan et al ., ; Neogi et al ., ; Ganguly et al ., ; Chakraborty et al ., ; Catlos et al ., ; Dasgupta et al ., , ; Harris et al ., ; Dubey et al ., ; Chakraborty et al ., ; Gupta et al ., ; Faak et al ., ; Kellett et al ., ; Rubatto et al ., ; Anczkiewicz et al ., ; Mottram et al ., ,b, ,b; Neogi et al ., ; Sorcar et al ., ; Gaidies et al ., ; Landry et al ., ). We have used the references cited above, data from the reports of the Geological Survey of India (Chakrabarti et al ., ; Chakrabarti & Banerjee,…”

Section: General Geological Featuresmentioning

confidence: 99%

A review of thermal history and timescales of tectonometamorphic processes in Sikkim Himalaya (NEIndia) and implications for rates of metamorphic processes

Chakraborty

Anczkiewicz

Gaidies

et al. 2016

Journal Metamorphic Geology

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The lesser and greater Himalayan sequences (LH and GH) in Sikkim have been studied in detail recently. The LH consists mainly of pelitic lithologies with detrital zircon ages >1800 Ma and e Nd (0) of À27.7 to À23.4 (with intercalated calcsilicates, metabasites and a sheared granite gneiss -the Lingtse gneiss). The metamorphic sequence is characterized by (i) a remarkably continuous and systematic metamorphic field gradient (~60-70°C kbar À1 ), (ii) peak pressures as well as temperatures of metamorphism increasing at higher metamorphic grades (~5 kbar, 500°C at the garnet zone tõ 8 kbar, 700°C at the sillimanite-muscovite-zone), (iii) clockwise P-T paths of a tight 'hairpin' shape with a prograde slope of 20-30°C kbar À1 , (iv) initiation of garnet growth (Lu-Hf chronometry) at systematically older ages at higher grades (11-10.5 Ma at garnet zone to 16.8 Ma at sillimanite-K-feldspar zone), (v) peak of metamorphism simultaneously at all grades (13-11 Ma), (vi) deformed and folded metapelitic rocks but with little evidence of pervasive shearing and (vii) duration of melt formation and segregation on the order of a few 100,000 years. The degree of melting was low, as indicated by the presence of muscovite all through the sequence. This evidence indicates that the LH behaved as a coherent block, and thermomechanical models quantitatively reproduce many of these features as well as explain the formation of inverted metamorphic sequence in such a coherent block. The greater Himalayan sequence (GH), also largely metapelitic, has different protoliths (with components as young as 800 Ma) and a different metamorphic history (extensive migmatization at higher grades~8-12 kbar, 750-850°C at an older age of largely >20 Ma along a different clockwise P-T path characterized by sharp, isothermal decompression followed by near isobaric cooling). Geochronological data (monazite, zircon, garnet) as well as cooling rate calculations (geospeedometry) reveal that the GH is made up of at least two blocks with distinct, complex and multistage P-T-t histories. Different stages of the high-T cooling were rapid (100's°C Ma À1 to 10's°C Ma À1 at different stages) and at least some of it was unrelated to exhumation; synthesis of these results with low-T thermochronometry allows the detailed multistage cooling and exhumation history of this block to be reconstructed. The reconstructed cooling and exhumation histories show that a number of interlinked processes operating on a hierarchy of timescales leads to the overall evolution. The P-T history with rapid cooling can be reproduced by thermomechanical models that consider conductive as well as advective heat transport and there is no need to invoke additional processes (such as the role of fluids). Metabasic inclusions within both the LH and the GH appear to record a different (? older in part) history. The role of these in the overall evolution, as well as the difference in metamorphic ages of the LH and GH remain open questions that need to be addressed in future research.

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Role of initial basin width in partitioning total shortening in the Lesser Himalayan fold-thrust belt: Insights from regional balanced cross-sections

Cited by 19 publications

References 39 publications

Segmentation of the Main Himalayan Thrust Revealed by Low‐Temperature Thermochronometry in the Western Indian Himalaya

Segmentation of the Main Himalayan Thrust Revealed by Low‐Temperature Thermochronometry in the Western Indian Himalaya

Geometry and kinematics of the Darjeeling–Sikkim Himalaya, India: Implications for the evolution of the Himalayan fold-thrust belt

A review of thermal history and timescales of tectonometamorphic processes in Sikkim Himalaya (NEIndia) and implications for rates of metamorphic processes

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