Tectono-magmatic evolution of the west coast of india

Subrahmanya, K. R.

doi:10.1016/s1342-937x(05)70847-9

Cited by 26 publications

(5 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Towards the end of the Cretaceous Quiet Zone, at about 90 Ma, the spreading axis jumped eastwards and Madagascar separated from India in response to partial melting and doming of the lithosphere, which resulted in passive rifting. This resulted in passive rifting (Pande et al 2001; Storey et al 1995; Subrahmanya 1998). At around 70 Ma, the spreading axis jumped again to the east, following spreading in the Mascarene Basin (MB) and opening of the Gop Rift.…”

Section: Geotectonic Settingmentioning

confidence: 99%

Three dimensional lithospheric structure of the western continental margin of India constrained from gravity modelling: implication for tectonic evolution

Arora¹,

Tiwari²,

Singh³

et al. 2012

Geophysical Journal International

View full text Add to dashboard Cite

SUMMARY This paper describes a 3‐D lithospheric density model of the Western Continental Margin of India (WCMI) based on forward modelling of gravity data derived from satellite altimetry over the ocean and surface measurements on the Indian peninsula. The model covers the north‐eastern Arabian Sea and the western part of the Indian Peninsula and incorporates constraints from a wide variety of geophysical and geological information. Salient features of the density model include: (1) the Moho depth varying from 13 km below the oceanic crust to 46 km below the continental interior; (2) the lithosphere–asthenosphere boundary (LAB) located at depths between 70 km in the southwestern corner (under oceanic crust) and about 165 km below the continental region; (3) thickening of the crust under the Chagos–Laccadive and Laxmi Ridges and (4) a revised definition of the continent–ocean boundary. The 3‐D density structure of the region enables us to propose an evolutionary model of the WCMI that revisits earlier views of passive rifting. The first stage of continental‐scale rifting of Madagascar from India at about 90 Ma is marked by relatively small amounts of magmatism. A second episode of rifting and large‐scale magmatism was possibly initiated around 70 Ma with the opening of the Gop Rift. Subsequently at around 68 Ma, the drifting away of the Seychelles and formation of the Laxmi Ridge was a consequence of the down‐faulting of the northern margin. During this second episode of rifting, the northern part of the WCMI witnessed massive volcanism attributed to interaction with the Reunion hotspot at around 65 Ma. Subsequent stretching of the transitional crust between about 65 and 62 Ma formed the Laxmi Basin, the southward extension of the failed Gop Rift. As the interaction between plume and lithosphere continued, the Chagos–Laccadive Ridge was emplaced on the edge of the nascent oceanic crust/rifted continental margin in the south as the Indian Plate was moving northwards.

show abstract

Section: Geotectonic Settingmentioning

confidence: 99%

Three dimensional lithospheric structure of the western continental margin of India constrained from gravity modelling: implication for tectonic evolution

Arora¹,

Tiwari²,

Singh³

et al. 2012

Geophysical Journal International

View full text Add to dashboard Cite

show abstract

“…1-km high and more than 1500-km long megageomorphological feature is considered as the rift shoulder. It is now believed that this great escarpment of India was initiated as a continental edge at the time of the separation of the Seychelles microcontinent following the eruption of the Deccan Trap lavas in late Cretaceous (Widdowson 1997;Subrahmanya 1998;Gunnell and Fleitout 2000;Chand and Subrahmanyam 2003).…”

Section: Introductionmentioning

confidence: 99%

“…During the last four decades different researchers have postulated or deduced sustained uplift along the western continental margin of India (Athavale and Anjaneyulu 1972;Kailasam 1975;Powar 1981;Ollier and Powar 1985;Powar 1993;Radhakrishna 1993;Widdowson and Cox 1996;Widdowson 1997;Subrahmanya 1998;Widdowson and Mitchell 1999;Campanile et al 2008;Mukhopadhyay et al 2008). Based on Bouguer gravity anomalies, Kailasam (1975) identified areas of uplift in Nasik and Sangola;and Power (1981) attributed the typical lineament pattern in DBP to regional uplift.…”

Section: Introductionmentioning

confidence: 99%

Uplift along the western margin of the Deccan Basalt Province: Is there any geomorphometric evidence?

Kale

Shejwalkar

2008

J Earth Syst Sci

View full text Add to dashboard Cite

In line with the passive margin landscape evolutionary model in vogue, sustained erosion and long-distance retreat of the Western Ghat escarpment are widely considered to be the results of erosionally-driven isostatic uplift since Tertiary by many workers. Others have postulated or adduced evidence for strong neotectonic activity in the Ghat region. An obvious question in this regard is whether there is any geomorphometric evidence in support of this widespread view? In order to test the hypothesis of ongoing post-rift fexural uplift or neotectonic activity in the western Deccan Basalt Province (DBP), geomorphometric analysis was carried out and commonly used geomorphic indices of active tectonics (GAT) were derived for 30 selected river basins on both sides of the Western Ghat. SRTM-DEM data and ArcGIS were used to derive the indices. Tectonic geomorphic analysis based on five proxy indicators suggests that the differences in GAT indices, both along strike and across the Western Ghat, are statistically insignificant. The index values are nowhere close to the GAT values typically associated with drainage basins affected by active tectonics and deformation. Mapping of the indices reveals lack of discernable trends. The adduced results indicate that the western DBP belongs to the class of relatively low tectonic activity.

show abstract

“…The seismogenic zone is distributed in a ~20 km × 30 km area, on either side of the elevated, nearly coast‐parallel, Western Ghats escarpment, roughly covering the region between the Koyna reservoir in the north and the Warna reservoir in the south. The escarpment is believed to be a result of differential erosion and scarp retreat following India's rifting and separation from Seychelles and its evolution after the Deccan volcanic eruption (Subrahmanya, ; Widdowson, ). Scientific drilling carried out during 2012–2014 provided the first direct estimate of the thickness of the Deccan traps (412–1,251 m) in the seismogenic zone and revealed that they are underlain directly by granitic basement rocks with no infratrappean sediments in between (Gupta et al, ; Roy et al, ).…”

Section: Geologic and Tectonic Settingmentioning

confidence: 99%

In Situ Stress Orientation From 3 km Borehole Image Logs in the Koyna Seismogenic Zone, Western India: Implications for Transitional Faulting Environment

2020

View full text Add to dashboard Cite

Knowledge of the in situ stress regime is critical to investigate the genesis of recurrent triggered seismicity over the past five decades in the Koyna seismogenic zone. Orientations of in situ horizontal stresses are determined for the first time from analyses of image logs in a 3 km deep scientific borehole KFD1 in the area. KFD1 passed through 1,247 m thick Deccan Traps and continued 1,767 m in the granitic basement. Stress-induced wellbore failures, breakouts and drilling-induced tensile fractures, are identified in the acoustic and microresistivity images of the granitic basement. Additionally, tightly constrained focal mechanisms of 50 earthquakes of M ≥ 3.6, reported in literature, are inverted to constrain the stress regime. Salient results are as follows: (i) wellbore breakouts and drilling-induced tensile fractures constrain N9°W ± 17°orientation for maximum horizontal principal stress (S Hmax ); (ii) consistency with the regional NNW-SSE orientation of S Hmax from inversion of earthquake focal mechanisms shows that the borehole data are representative for the Koyna region; (iii) breakout rotations at multiple depths below 2,100 m indicate that the borehole may have passed through localized fault damage zones; (iv) consistent strike azimuths of steeply dipping fractures with S Hmax orientation indicate favorable conditions for strike-slip to normal transitional faulting environment; and (v) stress inversion of 50 well-determined earthquake focal mechanisms supports transitional faulting environment in the Koyna seismogenic zone. Thus, stress orientation and fracture information from borehole data, together with stress regime constrained from inversion of earthquake focal mechanisms, shed new light on the faulting environment in the region.

show abstract

Tectono-magmatic evolution of the west coast of india

Cited by 26 publications

References 14 publications

Three dimensional lithospheric structure of the western continental margin of India constrained from gravity modelling: implication for tectonic evolution

Three dimensional lithospheric structure of the western continental margin of India constrained from gravity modelling: implication for tectonic evolution

Uplift along the western margin of the Deccan Basalt Province: Is there any geomorphometric evidence?

In Situ Stress Orientation From 3 km Borehole Image Logs in the Koyna Seismogenic Zone, Western India: Implications for Transitional Faulting Environment

Contact Info

Product

Resources

About