Tectonic studies and crustal shortening across Easternmost Arunachal Himalaya

Ningthoujam, P. S.; Dubey, C. S.; Lolee, L. K.; Shukla, Dericks Praise; Naorem, S.S; Singh, Sushmita

doi:10.1016/j.jseaes.2015.07.003

Cited by 25 publications

(11 citation statements)

References 44 publications

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“…Restoration of the section yields undeformed horizontal length (L o ) of 324 km and a minimum shortening estimate of 280 km, equivalent to a ~86% strain (Figure 7). Similar shortening strain values of ~83% and ~86% were constrained by Ningthoujam et al (2015) and Salvi et al (2020), respectively, despite different interpretations to the subsurface structural geometry along Dibang Valley.…”

Section: Restored Cross Sectionsupporting

confidence: 75%

“…Shortening estimates across the Eastern Flanking Belt can also be used to test models of orogen‐parallel variations of Cenozoic strain, specifically (1) shortening increases west to east due to spatial variations in India‐Asia convergence (Dewey et al, 1989; Guillot et al, 1999; Patriat & Achache, 1984), (2) shortening variations are controlled by the precollisional stratigraphic and structural configurations of Greater India and/or the Lhasa terrane (Long et al, 2011), or (3) maximum shortening occurs at the orogen center (Elliott, 1976). However, few Cenozoic crustal shortening estimates have been available for the Eastern Flanking Belt based on systematic geologic mapping, rigorous palinspastic reconstruction, and high‐resolution age constraints (Ningthoujam et al, 2015; Salvi et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

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Structural and Thermochronologic Constraints on the Cenozoic Tectonic Development of the Northern Indo‐Burma Ranges

et al. 2020

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The~1,500-km-long, north trending Eastern Flanking Belt of the Himalayan-Tibetan orogenic system is located along the eastern margin of the Indian subcontinent. Although the belt is a key element of the Cenozoic India-Asia collisional zone, its tectonic evolution remains poorly understood. This lack of knowledge has impacted our ability to differentiate between competing hypotheses for the evolution of the India-Asia collision. To address this problem, we integrate constraints on the structural framework and magnitude of Cenozoic shortening strain with thermochronology of the northernmost segment of the belt located directly southeast of the eastern Himalayan syntaxis (i.e., the northern Indo-Burma Ranges). The study area exposes a southwest directed thrust belt that is bounded by the Indian craton in the west and the right-slip Jiali fault zone in the east. New and existing (U-Th)/He and 40 Ar/ 39 Ar thermochronologic data indicate that thrust-related cooling occurred from~36 Ma in the northeast to~5.6 Ma in the southwest. Episodes of out-of-sequence thrusting occurred at~30-20,~14-12, and~11-6 Ma within the thrust belt. Restoration of the thrust belt yields a minimum horizontal shortening of~280 km (~86%). These results combined with (1) the recorded local absence of several major Himalayan-Tibetan lithologic units (i.e., Tethyan Himalayan Sequence, Greater Himalayan Sequence, and southern Gangdese batholith) and (2) the southward decrease in the thrust-belt width (33-5 km) suggest a complex history of thrusting in the northern Indo-Burma Ranges and an spatial increase in Cenozoic crustal shortening and/or continental underthrusting from west to east across the eastern Himalayan syntaxis.

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Section: Restored Cross Sectionsupporting

confidence: 75%

Section: Introductionmentioning

confidence: 99%

Structural and Thermochronologic Constraints on the Cenozoic Tectonic Development of the Northern Indo‐Burma Ranges

et al. 2020

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“…Black arrows are the locations of Bhismak Fort (purple ellipse) and Manabhum Anticline (MA). to its higher thickening and steep plunge, which is not the case and hence negates the previously speculated notion of high crustal shortening in this region (Haproff et al, 2018;Ningthoujam et al, 2015). These observations suggest the growth of MHT toward foreland through time at about the same rate while maintaining its "locked zone width".…”

Section: Discussionsupporting

confidence: 41%

Evidence of the 1950 Great Assam Earthquake Surface Break Along the Mishmi Thrust at Namche Barwa Himalayan Syntaxis

Singh

Pandey

Mishra

et al. 2021

Geophysical Research Letters

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“…1). Previous geological studies have established the first-order lithologic framework of the northern Indo-Burma Ranges (e.g., Wadia, 1931;Nandy, 1973;Thakur and Jain, 1975;Acharyya, 1980Acharyya, , 1987Sharma et al, 1991;Singh, 1993;Misra and Singh, 2002;Gururajan and Choudhuri, 2003;Goswami, 2008Goswami, , 2011Misra, 2009;Sarma et al, 2009;Sarma et al, 2012;Goswami, 2013aGoswami, , 2013bSharma and Sarma, 2013;Ningthoujam et al, 2015). Most recently, Haproff et al (2018) divided the exposed rocks into six lithologic units , which from northeast to southwest consist of: (1) igneous rocks of the Lohit Plutonic Complex (Fig.…”

Section: Northern Indo-burma Rangesmentioning

confidence: 99%

Geologic framework of the northern Indo-Burma Ranges and lateral correlation of Himalayan-Tibetan lithologic units across the eastern Himalayan syntaxis

et al. 2019

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The Cenozoic India-Asia collision generated both the east-trending Himalayan orogen and the north-trending Eastern and Western Flanking Belts located along the margins of the Indian subcontinent. Although the tectonic development of both flanking belts is key to understanding mechanisms of continental deformation during indenter-induced collision, few field-based studies coupled with geochronological and geochemical methods have been applied to these tectonic domains. In this study, we investigate the lateral correlation of lithologic units between the northern Indo-Burma Ranges, the northernmost segment of the Eastern Flanking Belt, and the eastern Himalayan-Tibetan orogen by integrating field observations, U-Pb zircon geochronology, and whole-rock geochemistry. Our findings provide new quantitative constraints to interpretations that the northern Indo-Burma Ranges expose the eastward continuation of several lithologic units of the Himalayan orogen and Lhasa terrane. Our field work documents a stack of thrust-bounded lithologic units present in the study area. The northernmost and structurally highest Lohit Plutonic Complex consists of Mesoproterozoic basement rocks (ca. 1286 Ma) and Late Jurassic-Cretaceous granitoids (ca. 156-69 Ma) with positive ε Nd values and initial 87 Sr/ 86 Sr ratios of ~0.705, which are correlative to the Bomi-Chayu complex and the northern Gangdese batholith, respectively. The structurally lower Tidding-Mayodia mélange complex, composed of basalt, gabbro, ultramafic rocks, and mafic schist of a dismembered ophiolite sequence, is interpreted in this study as the eastward extension of the Indus-Yarlung suture zone. Structurally below the suture zone are the Mayodia gneiss and Lalpani schist, which are interpreted to correlate with the Lesser Himalayan Sequence based on comparable metamorphic lithologies, negative ε Nd values, and similar Mesoproterozoic-Cambrian detrital zircon age spectra. In contrast to the above metamorphic units, the structurally lowest Tezu unit consists of siliciclastic strata that may be correlated with the Miocene-Pliocene Siwalik Group of the Himalayan orogen. Despite the above correlations, notable Himalayan-Tibetan lithologic units are absent in the northern Indo-Burma Ranges, including the Mesozoic-Cenozoic southern Gangdese batholith belt and its cover sequence of the Linzizong volcanic rocks, Xigaze forearc basin, Tethyan Himalayan Sequence, and Greater Himalayan Crystalline Complex of south-central Tibet and the central Himalaya. We interpret the absence of these lithologic units to be a result of a greater magnitude of crustal shortening and/or underthrusting of the Indian cratonal rocks than that across the Himalayan orogen to the west. This interpretation is supported by a southward decrease in the map-view distance between the active range-bounding thrust and the Indus-Yarlung suture zone in the northern Indo-Burma Ranges, from ~200 km in the north near the eastern Himalayan syntaxis to ~5 km in the south across a distance of ~200-300 km.

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Tectonic studies and crustal shortening across Easternmost Arunachal Himalaya

Cited by 25 publications

References 44 publications

Structural and Thermochronologic Constraints on the Cenozoic Tectonic Development of the Northern Indo‐Burma Ranges

Structural and Thermochronologic Constraints on the Cenozoic Tectonic Development of the Northern Indo‐Burma Ranges

Evidence of the 1950 Great Assam Earthquake Surface Break Along the Mishmi Thrust at Namche Barwa Himalayan Syntaxis

Geologic framework of the northern Indo-Burma Ranges and lateral correlation of Himalayan-Tibetan lithologic units across the eastern Himalayan syntaxis

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