Indra Bir Singh

Heavy Metals in Freshly Deposited Stream Sediments of Rivers Associated with Urbanisation of the Ganga Plain, India

Freshly deposited stream sediments from six urban centres of the Ganga Plain were collected and analysed for heavy metals to obtain a general scenery of sediment quality. The concentrations of heavy metals varied within a wide range for Cr (115–817), Mn (440–1 750), Fe (28 700–61 100), Co (11.7–29.0), Ni (35–538), Cu (33–1 204), Zn (90–1 974), Pb (14–856) and Cd (0.14–114.8) in mg kg-1. Metal enrichment factors for the stream sediments were <1.5 for Mn, Fe and Co; 1.5–4.1 for Cr, Ni, Cu, Zn and Pb; and 34 for Cd. The anthropogenic source in metals concentrations contributes to 59% Cr, 49% Cu, 52% Zn, 51% Pb and 77% Cd. High positive correlation between concentrations of Cr/Ni, Cr/Cu, Cr/Zn, Ni/Zn, Ni/Cu, Cu/Zn, Cu/Cd, Cu/Pb, Fe/Co, Mn/Co, Zn/Cd, Zn/Pb and Cd/Pb indicate either their common urban origin or their common sink in the stream sediments. The binding capacity of selected metals to sediment carbon and sulphur decreases in order of Zn > Cu > Cr > Ni and Cu > Zn > Cr > Ni, respectively. Stream sediments from Lucknow, Kanpur, Delhi and Agra urban centres have been classified by the proposed Sediment Pollution Index as highly polluted to dangerous sediments. Heavy metal analysis in the <20-μm-fraction of stream sediments appears to be an adequate method for the environmental assessment of urbanisation activities on alluvial rivers. The present study reveals that urban centres act as sources of Cr, Ni, Cu, Zn, Pb and Cd and cause metallic sediment pollution in rivers of the Ganga Plain.

Hardgrounds, reworked concretion levels and condensed horizons in the Jurassic of western India: their significance for basin analysis

Jurassic sediments in the shallow pericratonic basins of Kachchh and Rajasthan, western India, exhibit numerous signs of reduced sedimentation, omission, erosion and in situ reworking, in combination with synsedimentary cementation. Hardgrounds developed on carbonate shoals in the Bathonian of Rajasthan, whilst reworked concretion levels are characteristic of offshore siliciclastic sediments of the Callovian of Kachchh. A prominent marker horizon, the Oxfordian Dhosa Oolite Member, occurs throughout much of the Kachchh sub-basin and is a highly condensed unit characterized by hardgrounds, intraformational cobbles, reworked concretions, stromatolitic iron crusts, iron oncoids, and shell lags. Hardgrounds, reworked concretion levels, and condensation horizons are interpreted as the preserved relicts of transgressive pulses. Such pulses were possibly controlled by eustatic rise of sea level. Of at least equal importance, however, was a tectonic control which is demonstrated by the presence of small neptunian dykes, boulder beds derived from small submarine cliffs and rapid lateral facies and thickness changes in the Dhosa Oolite Member. These indications of extensional tectonics are thought to be connected to rifting and initial sea floor spreading between Africa and India.

Luminescence chronometry and Late Quaternary geomorphic history of the Ganga Plain, India

Abstract Flexing of the Indian lithosphere due to the continent–continent collision and thrust fold loading produced the Gangetic Foreland Basin during the Middle Miocene. The basin attained its present configuration during the Late Quaternary. Neotectonics and climate change since the last interglacial influenced the evolution of the present landscape of the Gangetic (Ganga) plains. The regional geomorphic surfaces in these plains are: (1) Upland Interfluve Surface (T2); (2) Marginal Plain Upland Surface (MP); (3) Megafan Surface (MF); (4) Piedmont Fan Surface (PF); (5) River Valley Terrace Surface (T1); (6) Active Flood Plain Surface (T0). Minor geomorphic features comprise ponds, alluvial ridges, and small channels, which occur on the Upland Interfluve Surfaces. The present contribution reviews geomorphic processes that sculpted the basin landscape and, then, using the blue green-stimulated luminescence (BGSL) and infrared-stimulated luminescence (IRSL) ages provides a first order chronological framework for the relationship of major and minor geomorphic features to climate and tectonics. Luminescence dating of the Upland Interfluve Surface (T2) shows that formation of this surface started before 51 ka and continued at least up to 7 ka. Deposition in the Marginal Plain (MP) began at least at 76 ka and continued after 32 ka bracketing the evidence of a more humid climate during 50–40 ka. Sedimentation on the T2 and MP surfaces was synchronous. The top of these surfaces gives variable ages ranging from 48 to 7 ka, due to differential erosion of an undulatory topography caused by tectonic activity. Age upper bound for the initiation and termination of the final building phase of Ganga Megafan can be placed at ∼26 ka and ∼22 ka respectively. Deposition on Piedmont Fan Surface continued between 8 and 3 ka. The River Valley Terrace Surface (T1) of Ganga River shows the activity of Yazoo type channels during 3–1.1 ka. The last phase of active accretion on the narrow, poorly developed youngest Active Flood Plain Surface (T0) was after 1.5 ka. The ponds of T2 surface formed due to cessation of fluvial activity sometime during 8–6 ka. A prominent tectonic activity at 7–5 ka and dry climate at 5 ka produced undulatory topography and high siltation rates in the lakes and ponds. The peripheral bulge, southern Ganga Plain has been tectonically active causing deep incision of rivers and a 40-ka seismic event, and Mid–Late Holocene tectonic activity can be inferred.

Geogenic distribution and baseline concentration of heavy metals in sediments of the Ganges River, India

Abstract The search for a better understanding of heavy metal distribution in large river sediments is a major concern in the exogenic cycling of elements through fluvial processes and in assessing the effects of anthropogenic influences. From the Asian continent, the Ganges River contributes a significant amount of sediments to the worlds ocean. Freshly deposited sediments of the Ganges River were analyzed from 27 locations along the 1700-km-long channel length by atomic absorption spectrophotometry to determine heavy metal concentration. Total metal concentration in the 3 tons Cr; 1313×10 3 tons Mn; 30,020×10 3 tons Fe; 14×10 3 tons Co; 35×10 3 tons Ni; 41×10 3 tons Cu; 78×10 3 tons Zn; 0.43×10 3 tons Cd and 16.4×10 3 tons Pb annually to the Bay of Bengal. The extensive physical weathering of the Himalayas and monsoon-controlled fluvial process results in the strong homogenization in heavy metal distribution in the river sediments.

Early Eocene warming events and the timing of terrestrial faunal exchange between India and Asia

The timing of initiation of continent-continent collision between Asia and India is controversial, but this major tectonic event is generally thought to have occurred in the Early Eocene, ca. 50 Ma. New and independent data from strontium isotopes, stable carbon isotopes, microfossil biostratigraphy, and mammal fossils from an Early Eocene marginal marine sequence (Cambay Shale) at the Vastan Lignite Mine of western India indicate that terrestrial faunal exchanges, and therefore continental collision, between Asia and the Indian subcontinent took place before 53.7 Ma. This age coincides with the second Eocene Thermal Maximum (ETM2), a short-lived warming episode that followed the Paleocene-Eocene Thermal Maximum (PETM) ca. 55.5 Ma. Our data also document, for the first time, a clear record of the ETM2 in terrestrial organic material from a low-latitude site, which is represented by a 3‰−4‰ carbon isotope excursion (CIE) in lignite and dispersed organic carbon δ13C values. The magnitude of the CIE at this location closely matches that observed in marine cores from the Arctic Ocean, which supports an interpretation that this hyperthermal event, though of lower magnitude, was similar in character to that of the PETM, being a global phenomenon that affected both terrestrial and marine ecosystems.

Faunal response to transgressive−regressive cycles : example from the Jurassic of western India

Abstract Upper Callovian to Oxfordian shelf sediments at Ler in the Kachchh Basin, western India, are interpreted in terms of transgressive-regressive cycles. The transgressive phases are represented by thin layers of reworked and bored concretions, sometimes in association with skeletal concentrations, the regressive phases are documented by much thicker units of largely fine-grained sediments. The benthic fauna of transgressive and regressive phases differes markedly and thus mirrors the sedimentary cycles: During transgressive phases non-sedimentation produced hard substrates colonized mainly by byssate, cemented, or pedicle-attached suspension-feeding epifaunal species, whilst sediment input during regressive phases lead to soft substrate conditions characterized by infaunal deposit- and suspension-feeders as well as by epifaunal opportunists. Whereas the composition of the “regressive fauna” remains fairly constant through time, that of successive “transgressive faunas” often differs drastically. This is possibly due to a greater environmental sensitivity of epifaunal taxa as compared to infaunal taxa.

Late Pleistocene¿Holocene hydrologic changes in the interfluve areas of the central Ganga Plain, India

Abstract Abandoned channel belts, ponds and point bar deposits of palaeochannels in the interfluve regions of the central Ganga Plain suggest changes in the morphohydrologic conditions during the Latest Pleistocene–Holocene. Stratigraphy of these ponds comprises channel sand at the base overlain by shell-bearing clayey silt. The contact of the two facies marks the phase when channels converted into standing water bodies. Point bar deposits of some palaeochannels are overlain by oxidised aeolian sand, indicating that the channel abandonment possibly occurred due to the desiccation and aridity in the region. Optically stimulated luminescence (OSL) chronometry of the pond sediments suggests that the deposition of the basal channel sand started before 13 ka and continued up to ∼8 ka. The ponds formed around 8–6 ka when the channel activity ceased. Evidence from the point bar deposits also indicates that the fluvial activity in the region ended sometime during 7–5 ka. This was followed by aeolian aggradation. The present study thus suggests that the hydrologic conditions in the Gangetic plains, i.e. initiation of channels and their abandonment, formation of microgeomorphologic features such as ponds and their eventual siltation, were controlled largely by climatic changes (i.e. monsoon changes) supported by tectonic activity. For the past 2 ka, increasing human and related agricultural activity has substantially accentuated the natural siltation rate of ponds.

Importance of geomorphology and sedimentation processes for metal dispersion in sediments and soils of the Ganga Plain: identification of geochemical domains

Abstract The Ganga Plain, one of the largest alluvial plains of the earth is under severe environmental stress due to rapid industrial and urban development and exploding population growth. Disposal of industrial and urban wastes and the ignorance of their management have resulted severe environmental problems, especially metal pollution. In the present study, an attempt is made to understand the transport and dispersion processes of metal contaminants in sediments and soils in Kanpur–Unnao industrial region of the Ganga Plain. The significance of geomorphology and monsoon rain is assessed in determining the distribution of contaminated sediments in this area. Three regional geomorphic surfaces (T0, T1 and T2) are identified, each with its characteristic river channel patterns and sediment distribution system which influence the dispersion and accumulation of the metal contaminants. The sediment and water distribution regime depends on the nature of geomorphic features and character of the river channels. Geomorphic features, sedimentation processes, the nature of the river channels and distribution of excess rain water of the monsoon season have given the bases to delineate five geochemical domains in the study area. Each geochemical domain is an independently operating system with its own geomorphic and geochemical characters. Chemical parameters (e.g., pH), metal concentrations, and dispersion of metal-contaminated sediments and soils vary from domain to domain. In comparison to reference values, each domain exhibits its own enrichment of elements, namely the Loni River domain has high contents of C-org, Cd, Cr, Zn; the Ganda Nala domain of C-org, Cu, Cr; the Ganga River domain of C-org, Cr, Cu, Pb, Sn, Zn; the Sewage Network domain of C-org, Cd, Cr, Cu, Pb, Ni, Sn, Zn; and the Pandu River domain of C-org, Cd, Cu, Ni, Zn. Patterns of changes in metal concentrations from one monsoon year to the other and in different seasons of a monsoon flood cycle are also domain specific. Each geochemical domain exhibits its own degree of metal enrichment in sediments and soils by anthropogenic activities and physico-chemical processes. Identification of geochemical domains with their specific physico-chemical processes in the fluvial system of the Ganga Plain will certainly help in assessing the environmental problems and land contamination of this region.

On the bedding in the natural-levee and the point-bar deposits of the Gomti river, Uttar Pradesh, India

Abstract Genesis of channel-fill “cross-bedding” and ripple-bedding units in the natural-levee and the point-bar deposits of the Gomti River is discussed. Channel-fill cross-bedding is produced because of development of and deposition in the crevasse-splays on the levees. Occasionally small-ripple bedding occurs, intricately interlayered with horizontal bedded units of upper-flow regime origin. Some of the horizontal bedding near the top of the point bars and levee is probably produced by setting of suspension clouds under low-energy conditions as a result of decrease in turbulence with receding water.

Mega- and giant ripples in the Ganga, Yamuna, and Son Rivers, Uttar Pradesh, India

Abstract Sand bars of the three important rivers of the Gangetic Alluvium, namely the Ganga, Yamuna and Son are investigated. Megaripples of undulatory type are the most abundant bed forms present, and are responsible for the development of large-scale cross-bedding, the most common bedding structure present in the area. Giant ripples, with superimposed megaripples are recorded in one sand bar in the Yamuna River. On a steeply sloping point bar in the Ganga River, delta-like lobes have produced foreset bedding oriented towards the main channel, at right angles to the direction of the main flow.