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Subsurface profiling of granite pluton using microtremor method: southern Aravalli, Gujarat, India

Joshi, AU and Sant, DA and Parvez, IA and Rangarajan, G and Limaye, MA and Mukherjee, S and Charola, MJ and Bhatt, MN and Mistry, SP (2018) Subsurface profiling of granite pluton using microtremor method: southern Aravalli, Gujarat, India. In: International Journal of Earth Sciences, 107 (1). pp. 191-201.

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Official URL: https://doi.org/10.1007/s00531-017-1482-9


We report, using the microtremor method, a subsurface granitic pluton underneath the Narukot Dome and in its western extension along a WNW profile, in proximity of eastern fringe of Cambay Rift, India. The dome and its extension is a part of the Champaner Group of rocks belonging to the Mesoproterozoic Aravalli Supergroup. The present finding elucidates development of an asymmetric double plunge along Narukot Dome. Microtremor measurements at 32 sites were carried out along the axial trace (N95°) of the dome. Fourier amplitude spectral studies were applied to obtain the ratio between the horizontal and vertical components of persisting Rayleigh waves as local ambient noise. Fundamental resonant frequencies with amplitude ≥1-sigma for each site are considered to distinguish rheological boundary. Two distinct rheological boundaries are identified based on frequency ranges determined in the terrain: (1) 0.2219–10.364 Hz recorded at 31 stations identified as the Champaner metasediment and granite boundary, and (2) 10.902–27.1119 Hz recorded at 22 stations identified as the phyllite and quartzite boundary. The proposed equation describing frequency–depth relationship between granite and overlaying regolith matches with those already published in the literature. The morphology of granite pluton highlights the rootless character of Champaner Group showing sharp discordance with granitic pluton. The findings of manifestation of pluton at a shallower depth imply a steep easterly plunge within the Champaner metasediments, whereas signature of pluton at a deeper level implies a gentle westerly plunge. The present method enables to assess how granite emplacement influences the surface structure.

Item Type: Journal Article
Publication: International Journal of Earth Sciences
Publisher: Springer Verlag
Additional Information: The copyright for this article belongs to the Authors.
Keywords: Aravalli; Champaner group; Granite pluton; H/V spectral analysis; Microtremor
Department/Centre: Division of Physical & Mathematical Sciences > Mathematics
Date Deposited: 03 Sep 2022 04:03
Last Modified: 03 Sep 2022 04:03
URI: https://eprints.iisc.ac.in/id/eprint/76386

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