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Deshpande, S. V.
- A Note on the Mode of Eruption of the Deccan Trap Lavas with Special Reference to Kutch
Authors
1 Oil & Natural Gas Commission, Baroda, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 14, No 2 (1973), Pagination: 134-141Abstract
On the basis of detailed field mapping and available gravity data, certain conclusions regarding the mode of eruption of Deccan trap lavas are drawn.
In Kutch, the Deccan trap formation outcrops along the western and southern periphery of the mainland. The trap flows which rest disconformably over the Mesozoic rocks, are also seen to cover the eroded Mesozoic structures. They thin out towards the central and northern hills of folded Mesozoic rocks. Whereas basic dykes and sills are concentrated in these fold zones, a number of plugs occur close to the Deccan trap outcrops. Igneous plugs, seem to be related more to the trap than the tectonism. The dykes and sills are probably syntectonic whereas the trap flows are post-tectonic with respect to the Mesozoic folding. Three volcanic cone-like structures have also been discovered at the fringe of the Deccan trap outcrop, near Jada and Wehar. It is therefore, concluded that the trap lavas in Kutch have mainly erupted from Hawaiian type shield volcanoes. The lavas erupted from such volcanic centres periodically and flowed to the south down the paleoslope towards the main volcanic field.
Positive gravity anomalies are noted around well known plugs of Saurashtra which have long been considered as the eruptive centres along tectonic lines. Similar anomalies which could also be interpreted as the subsurface volcanic plugs or cones, are seen within the major rift zones of Western India like Cambay and Narmada grabens and faulted west coast. Thus, the Deccan trap lavas of Peninsular India too might have erupted from Hawaiian type shield volcanoes situated along the major fracture zones.
- Mesozoic Sedimentary Model of Wagad Hills, Kutch, Western India
Authors
1 Institute of Petroleum Exploration, Oil and Natural Gas Commission, Kaulagarh Road, Dehra Dun 248 195, IN
2 Geology Department, M. S. University of Baroda, Baroda 390002, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 21, No 2 (1980), Pagination: 75-83Abstract
Wagad Hills in the eastern part of Kutch, Western India, mainly comprise of rocks ranging in age from middle Jurassic to lower Cretaceous encircled by a thin and narrow fringe of Tertiary sediments.
A sedimentary model of Wagad Hills is proposed comprising environments of deposition, basin geometry, lithic fill, lithic arrangement, directional structures and tectonic setting. The area experienced a prograding delta system with a gradual shift of strand line from east to west during the course of deposition.
- Geochronology of Miliolite Rocks of Kutch, Western India
Authors
1 Physical Research Laboratory, Ahmedabad 380009, IN
2 KDMIPE, Oil and Natural Gas Commission, Dehra Dun 248195, IN
3 Post-Graduate and Research Institute, Deccan College, Pune 411 006, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 33, No 6 (1989), Pagination: 588-593Abstract
Preliminary geochemical, mineralogical and geochronological studies using 230Th/234U method, of nine rniliolite rocks from Kutch are reported. The Kutch miliolites are characterised by lower CaCO3and higher quartz contents compared to their Saurashtra counterparts. The range of ages for the Kutch and Saurashtra miliolites are same and both can be accommodatedin the 50-70, 75-115 and > 140 K. Yr age groups proposed by Baskaran (1985).The origin of the Kutch miliolites, like those of Saurashtra, appears to be marine. Theories to explain their occurrence in Kutch have to await more detailed studies of this type alongwith ichnological and petrographic observations.