Decoupling between upper crustal deformation of southern Tibet and underthrusting of Indian lithosphere

Terra Nova ◽  
2021 ◽  
Author(s):  
Shiguang Wang ◽  
Anne Replumaz ◽  
Marie‐Luce Chevalier ◽  
Haibing Li
Keyword(s):  
Crustal Deformation ◽  
Southern Tibet ◽  
Indian Lithosphere

scholarly journals Tearing of Indian mantle lithosphere from high-resolution seismic images and its implications for lithosphere coupling in southern Tibet

2018 ◽  
Vol 115 (33) ◽  
pp. 8296-8300 ◽  
Author(s):  
Jiangtao Li ◽  
Xiaodong Song
Keyword(s):  
High Resolution ◽  
Crustal Deformation ◽  
Mantle Lithosphere ◽  
The West ◽  
Southern Tibet ◽  
Strongly Coupled ◽  
Intermediate Depth ◽  
Central Tibetan Plateau ◽  
Indian Lithosphere ◽  
Seismic Images

What happened to the Indian mantle lithosphere (IML) during the Indian–Eurasian collision and what role it has played on the plateau growth are fundamental questions that remain unanswered. Here, we show clear images of the IML from high-resolution P and S tomography, which suggest that the subducted IML is torn into at least four pieces with different angles and northern limits, shallower and extending further in the west and east sides while steeper in the middle. Intermediate-depth earthquakes in the lower crust and mantle are located almost exclusively in the high-velocity (and presumably strong) part of the Indian lithosphere. The tearing of the IML provides a unified mechanism for Late Miocene and Quaternary rifting, current crustal deformation, and intermediate-depth earthquakes in the southern and central Tibetan Plateau and suggests that the deformations of the crust and the mantle lithosphere are strongly coupled.

scholarly journals Record of Crustal Thickening and Synconvergent Extension from the Dajiamang Tso Rift, Southern Tibet

Geosciences ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 209
Author(s):  
William B. Burke ◽  
Andrew K. Laskowski ◽  
Devon A. Orme ◽  
Kurt E. Sundell ◽  
Michael H. Taylor ◽  
...  
Keyword(s):  
Dynamic Models ◽  
Hanging Wall ◽  
Crustal Thickness ◽  
Suture Zone ◽  
Crustal Thickening ◽  
Southern Tibet ◽  
South Central ◽  
Crustal Thinning ◽  
Indian Lithosphere ◽  
Central Tibet

North-trending rifts throughout south-central Tibet provide an opportunity to study the dynamics of synconvergent extension in contractional orogenic belts. In this study, we present new data from the Dajiamang Tso rift, including quantitative crustal thickness estimates calculated from trace/rare earth element zircon data, U-Pb geochronology, and zircon-He thermochronology. These data constrain the timing and rates of exhumation in the Dajiamang Tso rift and provide a basis for evaluating dynamic models of synconvergent extension. Our results also provide a semi-continuous record of Mid-Cretaceous to Miocene evolution of the Himalayan-Tibetan orogenic belt along the India-Asia suture zone. We report igneous zircon U-Pb ages of ~103 Ma and 70–42 Ma for samples collected from the Xigaze forearc basin and Gangdese Batholith/Linzizong Formation, respectively. Zircon-He cooling ages of forearc rocks in the hanging wall of the Great Counter thrust are ~28 Ma, while Gangdese arc samples in the footwalls of the Dajiamang Tso rift are 16–8 Ma. These data reveal the approximate timing of the switch from contraction to extension along the India-Asia suture zone (minimum 16 Ma). Crustal-thickness trends from zircon geochemistry reveal possible crustal thinning (to ~40 km) immediately prior to India-Eurasia collision onset (58 Ma). Following initial collision, crustal thickness increases to 50 km by 40 Ma with continued thickening until the early Miocene supported by regional data from the Tibetan Magmatism Database. Current crustal thickness estimates based on geophysical observations show no evidence for crustal thinning following the onset of E–W extension (~16 Ma), suggesting that modern crustal thickness is likely facilitated by an underthrusting Indian lithosphere balanced by upper plate extension.

Paleomagnetic study of the Eocene Quxu pluton of the Gangdese belt: Crustal deformation along the Indus-Zangbo suture zone in southern Tibet

1991 ◽  
Vol 107 (2) ◽  
pp. 369-379 ◽  
Author(s):  
Yo-ichiro Otofuji ◽  
Jun Kadoi ◽  
Shoubu Funahara ◽  
Fumiyuki Murata ◽  
Xilan Zheng
Keyword(s):  
Crustal Deformation ◽  
Suture Zone ◽  
Southern Tibet ◽  
Paleomagnetic Study

Palaeoslab and plume signatures in the mantle transition zone beneath Eastern Himalaya and adjoining regions

2020 ◽  
Vol 221 (1) ◽  
pp. 468-477
Author(s):  
Dipankar Saikia ◽  
M Ravi Kumar ◽  
Arun Singh
Keyword(s):  
Transition Zone ◽  
Broad Band ◽  
Receiver Functions ◽  
Eastern Himalaya ◽  
Bengal Basin ◽  
Southern Tibet ◽  
Data Set ◽  
Mantle Transition Zone ◽  
Tomographic Images ◽  
Indian Lithosphere

SUMMARY A comprehensive data set of 73 876 high quality receiver functions computed using waveforms recorded by 327 broad-band seismic stations is used to investigate the mantle transition zone (MTZ) structure beneath the eastern Himalaya, southern Tibet, Assam valley and the previously unexplored Burmese arc and Bengal basin regions. A highly variable and perturbed mantle transition zone, with depressed 410 and 660 km discontinuities, is observed beneath the Bengal basin and to the east of the eastern Himalayan syntaxis. The 410 is elevated by ∼10 km along the Himalayan collision front, while it deviates in the range of ±5 km beneath most parts of Tibet and the Himalayan Foredeep. In northern Tibet and along the Red River Fault, delayed conversions from the 410 reveal a deepening of more than 10 km. The 410 and 660 km discontinuities are uplifted by nearly 10 km beneath the Arunachal Himalaya, due to the presence of a subducting Indian lithosphere, as evident in the regional tomographic images. We observe a thick (>20 km) transition zone beneath the Burmese Arc and close to the Tengchong volcano. An uplifted 410 together with a depressed 660 km discontinuity requires presence of lithospheric slabs within the MTZ. Delayed P-to-s conversions from the 410 and 660 km discontinuities in the proximity of the Jinsha suture zone seem to be consistent with the earlier results that invoke flow of a hot Tibetan asthenosphere into the mantle transition zone, as an explanation. Interestingly, results from the Bengal basin reveal a deepening (∼10 km) of both the 410 and 660 km discontinuities. Similar results from other plume affected regions prompt us to interpret this as a signature of the Kergulean plume.

Combining geophysical and petrological estimates of the thermal structure of southern Tibet

2020 ◽  
Author(s):  
Tim Craig ◽  
Peter Kelemen ◽  
Bradley Hacker ◽  
Alex Copley
Keyword(s):  
Middle Miocene ◽  
Thermal Structure ◽  
The Tibetan Plateau ◽  
Crustal Material ◽  
Recent Past ◽  
Southern Tibet ◽  
Indian Lithosphere ◽  
Earthquake Distribution ◽  
Central Tibet ◽  
Geochemical Constraints

<p>The thermal structure of the Tibetan plateau remains largely unknown. Numerous avenues, both geophysical and petrological, provide fragmentary pressure/temperature information, both at the present, and on the evolution of the thermal structure over the recent past. However, these individual constraints have proven hard to reconcile with each other. This study presents a series of models for the simple underthrusting of India beneath southern Tibet that are capable of matching all available constraints on its thermal structure, both at the present day and since the Miocene. Three consistent features to such models emerge: (i) present day geophysical observations require the presence of relatively cold underthrust Indian lithosphere beneath southern Tibet; (ii) geochemical constraints require the removal of Indian mantle from beneath southern Tibet at some point during the early Miocene, although the mechanism of this removal, and whether it includes the removal of any crustal material is not constrained by our models; and (iii) the combination of the southern extent of Miocene mantle-derived magmatism and the present-day geophysical structure and earthquake distribution of southern Tibet require that the time-averaged rate of underthrusting of India relative to central Tibet since the middle Miocene has been faster than it is at present.</p>

Author response for "Neo-Tethyan slab tearing constrained by Palaeocene N-MORB-like magmatism in southern Tibet"

2020 ◽  
Author(s):  
Ye Tian ◽  
Feng Huang ◽  
Jifeng Xu ◽  
Baodi Wang ◽  
Han Liu ◽  
...  
Keyword(s):  
Author Response ◽  
Southern Tibet ◽  
Slab Tearing
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