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Mahalik, N. K.
- Paleocurrent Studies in the South-Eastern Part of Gangpur Series
Authors
1 National Geophysical Research Institute, Hyderabad, IN
2 Regional Engineering College, Rourkela, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 11, No 1 (1970), Pagination: 68-73Abstract
Paleocurrent analysis of the south-eastern part of the Gangpur series, made from cross-bedded structures in the quartzites of Raghunathpalli and Birmitrapur stages, shows that during the deposition of the older Raghunathpalli stage, the currents were flowing in a north-north-east direction and at a later period during the deposition of upper Birmitrapur stage the current direction was predominantly north-north-west.
A new method has been suggested for correction of tectonic tilt of paleocurrent data.
- Metamorphism in the Eastern Part of Gangpur Series
Authors
1 National Geophysical Research Institute, Hyderabad, IN
2 Regional Engineering College, Rourkela, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 13, No 2 (1972), Pagination: 122-130Abstract
Metamorphism in the eastern part of Gangpur series and its relation to stratigraphy. structure, tectonics and granitic intrusion has been discussed. Three phases of metamorphic recrystallisation are observed. The early low grade metamorphic phase (M1) belonging to the green schist facies is related to the main movement phase (F1) which deformed the Gangpur series into a major synclinorium. The early phase was followed by the main phase of metamorphism (M2) belonging to the lower amphibolite facies. This phase represents the highest grade of metamorphism for this area. This phase is mainly post-tectonic in relation to the main movement phase (F1). It is believed to be a result of the granitic intrusion into the adjoining area, and has no relation to depth of burial or tectonic level. The progressive metamorphism of the early and main phase was followed by a late phase retrograde metamorphism (Ms) belonging to the greenschist facies.- Geology of the Contact between the Eastern Ghats Belt and North Orissa Craton, India
Authors
1 Department of Geology, Utkal University, Bhubaneswar-751 004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 44, No 1 (1994), Pagination: 41-51Abstract
The contact region of tile Eastern Ghats Belt (EGB) with the North Orissa Craton (NOC) in Orissa State was studied and certain new observations have been made. The contact is represented by a wide zone affected by several east-west running faults with fault fragments of both blocks interfingcred with each other. Portions of the fault zone have later given rise to Gondwana graben in which coal-bearing sediments were deposited covering the contacts. The stratigraphic relation between the two crustal blocks was difficult of interpretation because of intermingling of the fault slices and concealment of the contacts by granitic intrusion, Gondwana sedimentation and lateritic cover.
The Eastern Ghats Belt (EGB) is made up of granulite facies rocks consisting principally of khondalites, leptynites, quartzites, gamet-biotite schists, basic granulites, charnockites and gneisses, all migmatized to different degrees. They could be distinguished into two different assemblages: the Rengali assemblage, forming the northernmost fringe of the EGB and the Angul assemblage lying to the south of the Gondwana graben. Both differ in their lithologic characteristics. The North Orissa craton, on the other hand, consists of several sequences of low-grade supracrustals with or without Banded Iron Formation (BIF) associated with granitic intrusion of more than one generation. At places within the fault zone between the two blocks there are typical intrusions of nepheline syenite and chromite-bearing ultrabasics.
A tentative geological account around the contact of the two major crustal blocks has been presented. It is believed that the Eastern Ghats granulite rocks formed earlier to the BIF-bearing supracrustals and associated granite intrusives. Migmatization, charnockitization and alkali plutonism etc. were late Proterozoic events in the EGB (1.0 Ga-0.8 Ga) related to deep seated fault tectonics along the contact.
Keywords
Eastern Ghats Belt, North Orissa Craton, Tectonics.- A Study of the Morphological Features and Bore Hole Cuttings in Understanding the Evolution and Geological Processes in Mahanadi Delta, East Coast of India
Authors
1 C-73, H 1 G Duplex, Baramunda Housing Board Colony, Bhubaneswar - 751 003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 67, No Spl Iss 5 (2006), Pagination: 595-603Abstract
Mahanadi delta is a classical arcuate delta along the east coast of India formed around the confluence of river Mahanadi with the Bay of Bengal in Orissa state. It was formed during the Upper Pleistocene-Holocene period overlying a dark grey shell bearing sequence with a distinct unconformity. The subaerial part of the delta has been the product of sedimentation under fluvial and fluvio-marine environments where a variety of depositional energy systems were operative e g river flow, sea waves, tides, littoral drift and wind. A variety of geomorphological features e g , river channels, point bais palaeo-channels, natural levees, flood plains, beaches, palaeo-beach ridges, tidal flats, tidal swamps, tidal creeks, spits, bars, lagoons and aeolian sand dunes have been observed and studied. These morphologic features have distinct relation between energy conditions of deposition, sediment make up, topographic level and land use. Three shell bearing marine horizons have been observed in most borehole cuttings of which the bottom most horizon is of pre Pleistocene age while the rest two are within the deltaic sequence. The bottom most marine horizon is characterised by the presence of iron silicate oolite sand Oliva-Glycimeris shell association. Delta building has taken place by shifting of distributary channels and fluctuation of sea level. Four fluvial and marine stages have been identified e g , Kathjodi-Burdha-Pracli- Debi fluvial stages interacting with four corresponding strand lines. In general the sea was receding during the delta formation except a short transgression during the second stage of the deltaic evolution. The marine marginal part of Mahanadi Delta shows three distinct morphologic makeup (1) the southwestern sector is characterized by thick wide sandy beaches, (2) the central sector by narrow beach and alternating sequence of parallel paleo-beach ridges and tidal swales and (3) the northern sector by tidal flats and mangrove swamps. This is explained by the role of the prevalent wind in shaping coastal geomorphology. This aspect is very typical of Mahanadi Delta.Keywords
Mahanadi Delta, Geomorphological Features, Borehole Cuttings, Evolutronary History Sea Level Fluctuation Land Use, Orissa India.- Workshop on Geoscience Education in Secondary Schools
Authors
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 76, No 3 (2010), Pagination: 300-300Abstract
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