Possible magmatic underplating beneath the west coast of India and adjoining Dharwar craton: Imprint from Archean crustal evolution to breakup of India and Madagascar

Saikia, Utpal; Das, Ritima; Rai, S.S.

doi:10.1016/j.epsl.2017.01.004

Cited by 25 publications

(11 citation statements)

References 63 publications

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“…The lower crustal layer is found to have low shear velocities of 3.5-3.7 km/s and higher Vp/Vs (1.80-1.84) throughout the Fujian region that deduces compressional velocities of 6.37-6.80 km/s. These velocities are not fast enough to represent those of the underplated rocks which typically exceed 4.0 km/s for Vs (Saikia et al, 2017) and 7.0 km/s for Vp (Thybo and Artemieva, 2013). Rather, they are more consistent with the lower crustal rocks containing a mafic-ultramafic composition.…”

Section: Layered Crustal Structure and Its Implicationsmentioning

confidence: 88%

Bulk Crustal Properties and Layered Velocity Structure in Fujian, SE China: Constraints From P and S Receiver Functions

Goyal

Hung

2021

Front. Earth Sci.

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Multiple tectonic events since the Neoproterozoic era have framed the present-day lithosphere in the Fujian province affiliated with the eastern part of the South China Block. Comprehensive information of the crustal structure and bulk properties can aid to understand the geological features and tectonic processes of still much debate in this region. An attempt is made in this study to explore crustal thickness and internal velocities across Fujian using the teleseismic receiver functions (RFs). The H-V stacking of joint P and S RFs improves to simultaneously estimate crustal thickness, average Vp and Vs, and derived Vp/Vs ratio and bulk sound speed in three backazimuth sectors for each of 17 stations. Furthermore, a Neighborhood Algorithm nonlinear inversion of P RFs is employed to determine the layered structures of Vs and Vp/Vs beneath all the stations. Results indicate the crustal thickness varies from at most ∼35 km in northwest Fujian to 30–35 km in the inland mountains and 27–30 km in the southeastern coasts. The inferred Moho geometry is nonplanar or inclined across the Zhenghe-Dapu (ZD) and Changle-Zhaoan (CZ) fault zones, especially in the southern ZD fault area. The average Vp/Vs suggests that the crust is predominantly felsic in the Wuyi-Yunkai orogen and intermediate-to-mafic in the Cretaceous magmatic and metamorphic zones. A high-velocity upper crust along the coastline is revealed, which attributes to the Pingtan-Dongshan metamorphic belt. At the sites near the ZD fault zone, the intracrustal negative discontinuity occurs at a shallower depth of ∼15 km marking an abrupt Vs decrease into the low-velocity mid-to-lower crustal layer, probably linked to the closed paleo-rift basin remnants. The lower crust across the Fujian is generally characterized by relatively lower Vs and higher Vp/Vs (1.80–1.84) consistent with those of the mafic-ultramafic rocks, which do not support the proposed extensive magmatic underplating in the Late Mesozoic.

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Section: Layered Crustal Structure and Its Implicationsmentioning

confidence: 88%

Bulk Crustal Properties and Layered Velocity Structure in Fujian, SE China: Constraints From P and S Receiver Functions

Goyal

Hung

2021

Front. Earth Sci.

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“…It might be responsible for the accretion of magma at the base of the crust, which is represented by high-velocity subhorizontal lower crustal fabric. Additionally, the shear wave velocity structure derived from receiver function analysis of earthquake data suggest a high-velocity lower-crustal layer representing magmatic underplating 36 . The thickness of the underplated layer is ~ 3 km, ~ 11 km, and 18 km beneath the EDC, WDC, and west-coast region (see Fig.…”

Section: Seismic Reflection Datamentioning

confidence: 99%

Mechanism for epeirogenic uplift of the Archean Dharwar craton, southern India as evidenced by orthogonal seismic reflection profiles

Mandal

Rao

Karuppannan

et al. 2021

Sci Rep

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Plateaus, located far away from the plate boundaries, play an important role in understanding the deep-rooted geological processes responsible for the epeirogenic uplift and dynamics of the plate interior. The Karnataka plateau located in the Dharwar craton, southern India, is a classic example for the plateau uplift. It is explored using orthogonal deep crustal seismic reflection studies, and a mechanism for the epeirogenic uplift is suggested. A pseudo three-dimensional crustal structure derived from these studies suggests a regionally extensive 10 km thick magmatic underplating in the region. It is further constrained from active-source refraction and passive-source seismological data. We interpret the Marion and Reunion mantle plume activities during 88 Ma and 65 Ma on the western part of Dharwar craton are responsible for the magmatic underplating, which caused epeirogenic uplift. Flexural isostasy related to the onshore denudational unloading and offshore sediment loading is also responsible for the persisting uplift in the region. Plate boundary forces are found to be contributing to the plateau uplift. The present study provides a relationship between the mantle plumes, rifting, development of continental margins, plateau uplift, and denudational isostasy. Combination of exogenic and endogenic processes are responsible for the plateau uplift in the region.

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“…The velocity structures at different scales of the Indian lithosphere are studied by several researchers employing different approaches such as seismic body wave tomography (Ramesh et al, 1990(Ramesh et al, , 1993Kennett and Widiyantoro 1999;Kayal and Mukhopadhyay, 2002;Mishra et al 2003;Mandal and Pujol, 2006;Mishra 2013;Singh et al, 2015;Koulakov et al, 2018Koulakov et al, , 2015Raoof et al, 2017;, surface wave tomography (Bhattacharya, 1981;Acton et al, 2010), receiver functions (RF) (Rai et al, 2003;Gupta et al, 2003;Kiselev et al, 2008;Ravi Kumar et al, 2013;Kumar et al, 2007Kumar et al, , 2013, joint inversion of body and surface wave analyses (Rai et al, 2003;Julia et al, 2009;Saikia et al, 2017), body wave propagation (Krishna et al, 1999;Krishna and Ramesh, 2000), and by magnetotellurics (Gupta et al, 1996;Naganjaneyulu and Santosh, 2012;Pavan Kumar et al, 2017), heat flow (Negi et al, 1986;Roy and Rao, 2000) and xenolith studies (Babu et al, 2009). Lithospheric structures in different tectonic domains are summarized below.…”

Section: Velocity Structuresmentioning

confidence: 99%

Seismicity and structure of the Indian subcontin

Kayal

2020

Episodes

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Instrumentally recorded tectonic earthquakes The 1897 great Shillong plateau earthquake (M w 8.1) in NE India region is the first instrumentally recorded Indian earthquake that was registered outside India by a few global seismic stations. After this great event, the first Indian seismological observatory was established in Alipore (Kolkata) in 1899 under auspices of the India Meteorological Department (IMD) (Kayal, 2008). Since then the national seismological network is developed; today it consists of some 115 broadband seismic observatories including some cluster-networks in NE India and in different segments of the Himalayas. In addition to these, a cluster of some 21 broadband stations is in operation in Koyna-Warna region and a cluster of some 50 broadband and 50 strong-motion stations is in operation in Gujarat state under the auspices of the Institute of Seismological Research (ISR), a newly established Institute in 2006. With the upgraded national network, earthquakes down to magnitude M w 3.5 are fairly well located, and down to M w 2.0 by the cluster networks. Recently, the Ministry of Earth Sciences (MoES) established the National Centre for

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Possible magmatic underplating beneath the west coast of India and adjoining Dharwar craton: Imprint from Archean crustal evolution to breakup of India and Madagascar

Cited by 25 publications

References 63 publications

Bulk Crustal Properties and Layered Velocity Structure in Fujian, SE China: Constraints From P and S Receiver Functions

Bulk Crustal Properties and Layered Velocity Structure in Fujian, SE China: Constraints From P and S Receiver Functions

Mechanism for epeirogenic uplift of the Archean Dharwar craton, southern India as evidenced by orthogonal seismic reflection profiles

Seismicity and structure of the Indian subcontin

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