Lithospheric architecture below the Eastern Ghats Mobile Belt and adjoining Archean cratons: Imprints of India-Antarctica collision tectonics

Niptika Jana, Chandrani Singh*, Arun Singh, Tuna Eken, Arun Kumar Dubey, Abhisek Dutta, Arun Kumar Gupta

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

The investigation of the rigid lithospheric mantle architecture floating over the weaker hotter asthenosphere is key to understanding the plate tectonic evolution of the Eastern Ghats Mobile Belt and the adjoining Archean cratons. We present shear-wave velocity (VS) structure for the crust and upper-mantle below the Eastern Ghats Mobile Belt (EGMB) and adjacent Archean cratons. The lithospheric structure is constrained through 4–150 s fundamental-mode Rayleigh and Love-wave group velocity dispersion measurements, using regional (2°–30°) earthquakes recorded at 27 seismic stations installed along two distinct profiles. Velocity models are improved by joint inversion of resultant dispersion curves with receiver functions computed from the teleseismic P-waves. Observed variations in crustal and lithospheric architecture across the domains of the Eastern Ghats Province are implication of the deformations due to rifting and collision of India and East Antarctica in the context of assembly and breakup of Rodinia and Gondwana supercontinents. The cratons and the mobile belt are characterised by 34–38 km, ∼45 km thick heterogeneous crust and 120–160 km, 90–120 km thick lithospheres, respectively. The abrupt changes in the crustal thickness owes its origin to the collisional thrusting of the Eastern Ghats Province against the Archean cratons. Significant variations in the nature of Moho are also noted. The flat sharp cratonic Moho is distinct from the gradational Moho below the Eastern Ghats Province, possibly a signature of magmatic underplating below the mobile belt. The nature of the lithosphere-asthenosphere boundary (LAB) interpreted from the gradient change in velocity appears to be poorly-resolved. Therefore, we utilise radial anisotropy determined from the discrepancy between VSH and VSV based on Rayleigh and Love-wave velocities respectively, as a proxy. Our findings confirm the LAB through positive radial anisotropy (VSH > VSV) prevalent in the asthenospheric-mantle that is likely explained by flow-induced shear. Overall, the lithospheric architecture below the study area has been shaped through several deformational episodes that distinguish the multiple litho-tectonic units within the mobile belt. The loss of cratonic lithospheric keel can be attributed to the mantle plume given the Gondwanan trajectory of the Indian subcontinent over Kerguelen and Crozet hotspots.

Original languageEnglish
Pages (from-to)209-222
Number of pages14
JournalGondwana Research
Volume111
DOIs
Publication statusPublished - Nov 2022

Bibliographical note

Publisher Copyright:
© 2022 International Association for Gondwana Research

Funding

This study was conducted under the scientific project (IAI) aided by the Ministry of Earth Sciences, Govt. of India (MoES/P.O. Geosci. /37/2014). We thank Satish Maurya for making the Rayleigh wave local dispersion data available for use. Niptika Jana thanks Ashwani Kant Tiwari for his valuable feedback during the compilation of the manuscript. Tuna Eken acknowledges the financial support from Alexander von Humboldt Foundation (AvH) towards computational and peripheral resources. We would like to thank handling editor Vasanthi A. and three anonymous reviewers for their critical feedback that has considerably improved the manuscript. Each author has contributed in data curation, formulation of the research problem, writing and editing of the manuscript. The authors declare that this manuscript is original, has not been published before and not currently being considered for publication elsewhere. We confirm that the manuscript has been read and approved by all named authors. This study was conducted under the scientific project (IAI) aided by the Ministry of Earth Sciences, Govt. of India (MoES/P.O., Geosci. /37/2014). We thank Satish Maurya for making the Rayleigh wave local dispersion data available for use. Niptika Jana thanks Ashwani Kant Tiwari for his valuable feedback during the compilation of the manuscript. Tuna Eken acknowledges the financial support from Alexander von Humboldt Foundation (AvH) towards computational and peripheral resources. We would like to thank handling editor Vasanthi A. and three anonymous reviewers for their critical feedback that has considerably improved the manuscript.

FundersFunder number
Alexander von Humboldt-Stiftung
Ministry of Earth Sciences/37/2014
Inter-American Institute for Global Change Research

    Keywords

    • Eastern Ghats Mobile Belt
    • Gondwana fragmentation
    • Lithosphere-asthenosphere boundary
    • Radial anisotropy
    • Surface wave dispersion

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