Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Indra Bir Singh ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow, IN

Abstract

The paper incorporates the results of grain size and mineralogical investigations carried out on the clays of the Eocene Fuller's earth formation, collected from various localities in Rajasthan. The major clay mineral is palygorskite-attapulgite, The heavy mineral assemblage suggests a metamorphic provenance. The depositional environment of this Fuller's earth formation seems to be in alkaline, hypersaline coastal lagoons.

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Indra Bir Singh ¹

Affiliations
1 Geology Department, Lucknow University, Lucknow-226007, IN

Abstract

The Tal Formation in Mussorie area represents deposits of a shallow tidal sea. The basal black shale succession-with phosphorite, chert, and minor amounts of sandy layers and limestone bands is the deposit of a protected lagoon or embayment, followed by streaky siltstone facies, representing deposits of a protected tidal flat. Streaky siltstone shows characteristic features of mixed flat and mud flat of intertidal zone. The topmost thick quartzite succession is a deposit of a shoal complex of a tidal sea with rather high energy. Thus, from bottom towards top of the Tal succession, there is a gradual improvement in the circulation system, as well as increase in the energy of deposition. The fossiliferous shell limestone (Nilkanth Formation) is not a part of the Tal Formation, but represents deposits of a high-energy sand bar-shoal complex of a shallow tidal sea.

The Tal succession is devoid of any well defined body fossils and a Precambrian age is proposed. The fossil-bearing horizons occurring in association with the Tal Formation (hitherto considered to be part of Tal Formation) may belong to different age, namely, Carboniferous-Permian and Jurassic-Cretaceous; however, and these horizons do not appear to form part of the Tal succession.

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Indra Bir Singh ¹, Ajai Kumar Bhargava ¹, Vikram Rai ¹

Affiliations
1 Geology Department, Lucknow University, Lucknow-226 007, IN

Abstract

Study of sedimentary structures indicate that Krol succession of Mussoorie area represents deposits of a shallow tidal sea: Krol A-deposits of open sea tidal flats in intertidal-subtidal zone. Krol B - deposits of protected embayment Or lagoon, Krol C - open tidal flats to intertidal zone of restricted tidal flat, Krol D - algal mat facies of inner intertidal to supratidal zone with increased salinity, Krol E - intertidal zone. The algal mat facies of Krol E shows dominantly Loferite, fenestral dolomite or bird's eye dolomite, showing different types of shrinkage cracks e.g. sheet cracks, irregular fenestral fabric, shrinkage pores. The supratidal facies is quite abundant, represented by vuggy dolomite and bird's eye pisolitic dolomite.

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Indra Bir Singh ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226007, IN

Abstract

Nagthat quartzite shows well-developed sequences of a shallow tidal sea, and represents deposits of coastal sand bar/shoal complex and mixed flats. The sand bar deposits show large-scale cross-bedding of bar type, mega-ripple bedding and abundant planes of discontinuity. The mixed flat deposits show lenticular and flaser bedding, wavy bedding, tidal bedding, small ripple bedding, parallel bedding and laminated mud. Ripples showing characteristics of shallow-water and falling water-level environments are commonly present. In a typical Nagthat quartzite, sand bar deposits and mixed flat deposits alternate with each other in a cyclic manner. The Nagthat quartzite denotes deposit of a stable shelf association.

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Indra Bir Singh

Abstract

No Abstract.

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Indra Bir Singh ¹

Affiliations
1 University of Lucknow, IN

Abstract

No Abstract.

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Indra Bir Singh

Abstract

No Abstract.

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Indra Bir Singh ¹, Shashi Shekhar ¹, Shrish Chandra Agarwal ¹

Affiliations
1 Geology Department, Lucknow University, Lucknow 226007, IN

Abstract

Green Sandstone (Green Sand) of Lameta sediments, in Jabalpur area, makes a conspicuous basal lithounit of the succession. It is made up of clean sand without any shale intercalations, and ranges in grain size from medium to fine sand. Largescale cross-bedding in the form of large festoons is the most dominant structure, showing mostly a bipolar current pattern, where one direction is more prominent. The sandstone also exhibits branched Thalassinoides-type burrows. The Green Sandstone represents deposit of an estuarine channel with tidal influences exclusively by marine processes. The prominent southerly palaeocurrent direction at Chui Hill is interpreted as local ebb-current direction.

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Indra Bir Singh ¹, Vinal Shukla ¹, Vibhuti Raj ¹, Pushkar Nath Kapoor ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow - 226007, IN

Abstract

Skolithos, comprising of thin, simple, unbranched vertical burrows are sometimes quite abundant in the siltstone of Arenaceous Member (tidal flat deposits) of Lower Tal Formation. They occur together in dense population resembling 'pipe rock'. The Skolithos burrows are 3-5 cm in length, and 2-5 mm in diameter showing a distinct wall; rarely showing narrow funnel-like widening at the mouth. In some cases the Skolithos burrows are paired, separated by a thin wall; but do not join together.

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Indra Bir Singh ¹

Affiliations
1 Geology Department, Lucknow University, Lucknow 226 007, IN

Abstract

A prominent ca. 1.50 m thick unit of algal mat facies is recorded from the topmost part of the Syringothyris Limestone (Lower Carboniferous) showing development of well-defined columnar stromatolites. The columnar stromatolites are generally 4-8 cm long (maximum about 15 cm long), possessing a rugged outer margin showing sheathing; and often exhibit flattening and deformation of laminae near the top. The horizontal algal mat lamination exhibits thick laminae, some vuggy features, and bird's eye structure. Intertidal zone, with parts extending into supratidal, is inferred as the palaeoenvironment in this unit.

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Indra Bir Singh ¹, V. N. Bajpai ²

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226007, IN
2 Department of Geology, Delhi University, Delhi 110007, IN

Abstract

Gangetic Plain, an active foreland basin shows N to NE flowing rivers in the southern part, controlled by the basement lineaments; while in the central part most of the rivers flow SE to E, following partly the lineaments developed in response to the Himalayan tectonics. Analysis of the subsurface data in Hamirpur-Kanpur-Unnao region shows that just south of present-day Ganga River, along an E-W trending lineament major change in the alluvial thickness and facies has taken place. It is suggested that earlier (probably Middle Pleistocene) rivers from Peninsular India flowing upto Kanpur, shifted their course southwards, and onlapped by Himalayan rivers and their deposits. It is argued that in 'an active foreland basin, lineaments parallel to orogen may develop, some of them even as gravity faults affecting the basement. These lineaments have a strong control on drainage, and thickness of the alluvial fill.

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Indra Bir Singh ¹, V. N. Bajpai ², A. Kumar ¹, M. Singh ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226 007, IN
2 Department of Geology, Delhi University, Delhi 110 007, IN

Abstract

Gangetic plain shows distinct geomorphic surfaces formed in response to the climatic and base-level changes related to the sea-level fluctuations during Quaternary. Within the major river valleys, a distinct geomorphic surface (T₁) is developed, located about 5-10 m above the present-day flood plain (T₀). Study of these surfaces in the Ganga River valley near Kanpur demonstrates that T₁ -surface channel deposits assigned tentatively the date of the last interglacial (25-30 Ka) show meandering scars and coarser sediments (M₁ = 1.9 φ) than the present-day channel sands. The T₀-surface shows braided channels and finer sediments (M₁ = 3.4 φ). The Ganga River has undergone a river metamorphosis from meandering to braided-type during the last 25,000 years, accompanied by decrease in grain-size, and probable decrease in water budget and increase in sediment load. All the major rivers of the Gangetic Plain, many of them braided-type today, show evidence of having been meandering rivers during last interglacial (25-Ka).

Keywords

Geomorphology, Indo-Gangetic Plain, Ganga Pleistocene-Holocene, Quaternary Geology.

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Poornendu P. Singh ¹, Indra Bir Singh ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow-226 007, IN

Abstract

Silty sandstone beds in Bhuj Formation show predominantly large-scale cross-bedding showing herring-bone structure with rippled interbeds. A well-preserved large-scale cross-bedded unit shows distinct bundle structures which are interpreted as Lidal bundles. These tidal bundles are arranged in thin bundles of neap and thick bundles of spring cycle of a tidal rhythm. Bundle boundaries of neap cycle often show doublemud drapes. Presence of tidal bundles, double mud drapes, and neap-spring cycle within a single cross-bedded unit indicate significant role of tides during deposition of Bhuj Sandstone, and points to a tide-dominated coastal area as a site of deposition for Bhuj Sandstone.

Keywords

Sedimentology, Bhuj Sandstone, Cretaceous, Kachchh, Gujarat.

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Indra Bir Singh ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226 007, IN

Abstract

Flexural subsidence of the Indian lithosphere created the Ganga Plain foreland basin in front of the Himalayan orogen, which attained its present configuration during the late Quaternary Cirmate change, neotectonics and base level changes influenced the evolution of the present landforms of the Ganga Plain. The regional geomorphic surfaces are (1) Upland inteifluve Surface (T₂), (2) Marginal Plain Upland Surface (MP), (3) Megafan Surface (MF), (4) Piedmont Fan Surface (PF), (5) River Valley Terrace Surface (T₁) and (6) Active Flood plain Surface (T₀). The Upland interfluve Surface (T₂) is widespread reference surface, other surfaces are either incised or overlie this surface. Formation of these surfaces is essentially related to the climate cycles of late Pleistocene-Holocene( 128 ka BP). These surfaces ate depositional and have a succession of overlying sediments, younger than the time of formation of the respective surfaces.

The sediments coming from the Himalaya undergo significant chemical weathering in the alluvial plain where much Na, Ca, Sr, K, Mg, is removed, while As, Cr, Ni and Th are enriched. In suitable conditions smectite and kaolinite are formed. These sediments are partly eroded and transported to the delta region and beyond.

The Ganga Plain consists of a large number of river systems, originating in different parts of the Himalaya, Peninsular Craton, and alluvial plain formed at different times during the late Pleistocene-Holocene Surface runoff and groundwater are the main sources of water. It is difficult to make meaningful scheme of classification of channels. Based on the Sediment-Water transfer patterns, the channels are classified into three broad categories. The river systems are in different stages of evolution. The active perennial rivers are incised within the alluvium, and show avulsion on a scale of 10⁴ -10⁵years, some channels, part of the ancient anastomosing network, act as flood channels and show avulsion on a scale of 10¹- 10² years.

The Upland interfluve Surface (T₂) exhibits a number of microgeomorphic features which have helped in the reconstruction of the history of the Ganga Plain during the last ∼20 ka BP 20- 13 ka BP - new drainage of low density, 13-8 ka BP - extension of drainage system, high rainfall, 8-6 ka BP - channel disruption due to Base-Level rise and tectonics and formation of large lakes which retained most Water-Sediment of T₂-Surface, 6-4 ka BP - dry climate, increased terrigenous clastic sediments in lakes, 4-2 ka BP - increased siltation of the lakes, moderate rainfall, 2-0 ka BP - fragmentation and drying of lakes, strong anthropogenic influence. The basin exhibits active tectonism, which is mostly in the form of contractional system in the prominent zone, and prominent extensional system in the southern part of the basin One of the most significant events in Ganga Plain history is tectonics of 8-5 ka BP, which produced areas of centripetal drainages and changed the fluvial landscape into a landscape of ponds and lakes with few high grounds. It was helped by the climate change from humid to dry around 5 ka BP.

Keywords

Ganga Plains, Quaternary History, Terraces, Megafans, Palaeoclimate, Tectonics.

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Indra Bir Singh ¹

Affiliations
1 Department of Geology, Lucknow University, Lucknow 226007, IN

Abstract

Dhosa Oolite, 1-3 m in thickness, makes a distinctive lithostratigraphic unit in the Kachchh Basin, exhibiting a characteristic lithology of fossil-rich oolitic limestone, often nodular in appearance. It is characterized by the abundance of fossils, sometimes encrusted, absence of wave- or current-formed structures, dense burrowing, often recognizable as Thalassinoides burrows. The ammonoids of the different zones of Oxfordian age are commonly present; but often mixed up. These features suggest that the Dhosa Oolite is a transgressive condensation horizon representing the Oxfordian time span, related to the worldwide sea-level rise. The mixing of the fauna of various ammonite zones is probably a result of the combination of processes of slow rate of sedimentation, burrowing activity of the organisms, and storm events causing sediment reworking.

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