A biogeochemical study of the Podili and Tirupati area of Andhra Pradesh, India     

K. S. Reddy  K. S. S. Prasad  A. N. Raju 《Environmental Geology》1999,37(4):313-316

 The fluoride content of dung, urine and milk of grazing animals, for example cow, she-buffalo, doe and ewe, was studied in the Podili area, India, (endemic fluorosis) and also in Tirupati (non-fluorosis) for the purpose of comparison. The data reveal that the fluoride content of the urine of animals is suitable for the preparation of biogeochemical atlases studying the environmental effect in relation to health. Received: 1 August 1997 · Accepted: 2 March 1998  相似文献   

The changes in La Niña induced summertime interannual variability of sea level anomaly along the western boundary of the Bay of Bengal     

Mukherjee  Arnab  Ghosh  Supriyo 《Ocean Dynamics》2023,73(6):373-386

Ocean Dynamics - In this study, interannual variability and associated dynamics of sea level anomaly (SLA) along the western boundary of the Bay of Bengal (WBoB) during the summer...  相似文献   

3D upper crustal density structure of the Deccan Syneclise,Central India          下载免费PDF全文

K.N.D. Prasad  A.P. Singh  V.M. Tiwari 《Geophysical Prospecting》2018,66(8):1625-1640

A constrained 3D density model of the upper crust along a part of the Deccan Syneclise is carried out based on the complete Bouguer anomaly data. Spectral analysis of the complete Bouguer gravity anomaly map of the study region suggests two major sources: short wavelength anomalies (<100 km) caused primarily due to the density inhomogeneities at shallow crustal level and long wavelength anomalies (>100 km) produced due to the sources deeper than the upper crust. A residual map of the short wavelength anomalies is prepared from the complete Bouguer anomaly using Butterworth high‐pass filter (100 km cut‐off wavelength). Utilizing the constraints from deep resistivity sounding, magnetotellurics and deep seismic sounding studies, 2.5D density models have been generated along 39 profiles of this region. The mismatch between the calculated response of the a priori 2.5D model with the residual (short wavelength) gravity anomalies is minimized by introducing high‐density intrusive bodies (≥2.81 g/cm³) in the basement. With these 2.5D density models, the initial geometry of our 3D density model, which includes alluvium, Deccan trap, Mesozoic sediment and high‐density intrusive bodies in the basement up to a depth of 7 km (upper crust), is generated. In the final 3D model, Deccan trap extends from 200 m to nearly 1700 m below the 90–150 m thick Quaternary sediment. Further down, the sub‐trappean Mesozoic sediment is present at a depth range of 600–3000 m followed by the basement. The derived 3D density model also indicates six intrusive bodies of density 2.83 g/cm³ in the basement at an average depth of about 4–7 km that best fits the residual gravity anomaly of the study area.  相似文献   

Assessment of heavy metal pollution from the sediment of Tupilipalem Coast,southeast coast of India     

Sreenivasulu Ganugapenta  Jayaraju Nadimikeri  Sundara Raja Reddy Balam Chinnapolla  Lakshmanna Ballari  Rajasekhar Madiga  Nirmala K  Lakshmi Prasad Tella 《国际泥沙研究》2018,33(3):294-302

Sediment from twelve stations was sampled from the Tupilipalem Coast, southeast coast of India, and the presence of a set of heavy metals was established including iron (Fe), manganese (Mn), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), zinc (Zn) and cadmium (Cd). The heavy metals were assessed by factor analysis, the results of which showed positive and/or negative correlations among Fe, Mn, Cr, Cu, Ni, Pb, Zn, and Cd. Factor analysis also indicated that heavy metals in the sediments of the study area have different natural and anthropogenic sources. Similarly, a sediment pollution assessment was done using the Geoaccumulation Index (Igeo), Enrichment Factor (EF), and Pollution Load Index (PLI). The Geoaccumulation Index indicated that the surface sediment of the Tupilipalem Coast was extremely contaminated with Fe, Mn, Cr, Cu, Ni, Pb, and Zn. The calculation of enrichment factors showed a significant enrichment with respect to Pb, Zn, and Cd and a moderate enrichment with Cr, Cu, and Ni. The falling trend of average contents’ enrichment factors is Cd> Pb> Zn> Cu> Cr> Ni> Mn> Fe. The PLI values of the Cd show higher (>1) values due to the influence of distinct external sources like agricultural runoff, industrial activities, and other anthropogenic inputs. Ninety two percent of heavy metals under study showed the highest concentrations at station TP-5 where the Buckingham Canal and other agricultural and aquacultural effluents connect with the Bay of Bengal. This location is the second inlet which is periodically closed and it seemed that these parts of the study area are heavily affected by anthropogenic pollution.  相似文献   

Ichthyofauna (Chondrichthyes,Osteichthyes) from the Upper Cretaceous intertrappean beds of Piplanarayanwar,Chhindwara District,Madhya Pradesh,India          下载免费PDF全文

Ranjit Singh Lourembam  Guntupalli V. R. Prasad  Pooja Grover 《Island Arc》2017,26(1)

A new fossiliferous intertrappean section is found 92 km southwest of the extensively studied intertrappean beds of Mohgaonkalan and Jhilmili in Chhindwara District, Central India. Application of the bulk screen‐washing method led to the recovery of a rich microvertebrate fauna represented by fish, amphibians, crocodiles, snakes and dinosaurs. In this paper, the ichthyofauna recovered from the new intertrappean section consisting of Igdabatis indicus Prasad and Cappetta, 1993, Lepisosteus indicus Woodward, 1908, Osteoglossidae gen. et sp. indet., Pycnodontidae gen. et sp. indet. and Siluriformes indet. is described. The ichthyofauna dominantly represented by the teeth of Igdabatis indicus is suggestive of a nearshore, deltaic or estuarine palaeoenvironment and Late Cretaceous (Maastrichtian) age for the intertrappean beds. The remarkable similarity of the new intertrappean fauna to that of Asifabad and the infratrappean beds of Marepalli also is suggestive of coastal‐plain conditions all along the Godavari lineament in the Late Cretaceous. Although the presence of planktonic foraminifera in the intertrappean beds of Jhilmili in the Mandla Lobe of Deccan volcanic province has been inferred in terms of a short term marine incursion from the west coast along the Narmada lineament in the Early Palaeocene, currently there is no definitive evidence for the prevalence of marine or coastal‐plain conditions along the Narmada lineament at least in the latest Cretaceous.  相似文献   

Effect of autocorrelation on temporal trends in rainfall in a valley region at the foothills of Indian Himalayas     

Atul?Kant?PiyooshEmail author  Sanjay?Kumar?Ghosh 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(8):2075-2096

This study examines the effect of autocorrelation on step and monotonic trends in seasonal and annual rainfall. Initially, for step change, modified-Pettitt test is applied in two ways. First, using the corrected and unbiased trend-free-pre-whitening (TFPWcu) approach. Second, using a new approach in which time series is modelled by intervention analysis for modified Pettitt test. Subsequently, for monotonic trends, Mann–Kendall (MK) and six approaches of modified Mann–Kendall (MMK) test are applied to NCDC data for period 1901–2012 and its sub-periods. Approaches of MMK include pre-whitening (PW), trend-free-pre-whitening (TFPW), TFPWcu, two Variance Correction Approaches (VCAs) based on empirical formula (VCA:CF1) and Monte-Carlo-Simulations (VCA:CF2) and long term persistence (MK-LTP). A single change point is identified in 1970 for annual and monsoon rainfall from original and modified-Pettitt’s test using TFPWcu, while time series modelling approach has not exhibited any change point. Process shift in rainfall series is also studied using CUSUM and multiple change points are identified using Segment-Neighbourhood method. Outcomes of MMK show that TFPWcu is able to efficiently limit the effect of autocorrelation and may be preferred over PW and TFPW. The VCA:CF2 is not dependent on whole autocorrelation structure and corrects variance of all data series using lag-1 autocorrelation and may be preferred over VCA:CF1. MK-LTP considers long term persistence and it has exhibited presence of weaker trends than exhibited by other approaches. VCA:CF2 and MK-LTP are used to study trends of rainfall in Dehradun.  相似文献   

Monitoring field scale CO<Subscript>2</Subscript> injection from time-lapse seismic and well log,integrating with advanced rock physics model at Cranfield EOR site     

Ranjana Ghosh 《Acta Geophysica》2017,65(6):1207-1218

Causes and effects of global warming have been highly debated in recent years. Nonetheless, injection and storage of CO₂ (CO₂ sequestration) in the subsurface is becoming increasingly accepted as a viable tool to reduce the amount of CO₂ from the atmosphere, which is a primary contributor to global warming. Monitoring of CO₂ movement with time is essential to ascertain that sequestration is not hazardous. A method is proposed here to appraise CO₂ saturation from seismic attributes using differential effective medium theory modified for pressure (PDEM). The PDEM theory accounts pressure-induced fluid flow between cavities, which is a very important investigation in the CO₂-sequestered regime of heterogeneous microstructure. The study area is the lower Tuscaloosa formation at Cranfield in Mississippi, USA, which is one of the active enhanced oil recovery (EOR), and CO₂ capture and storage (CCS) fields. Injection well (F1) and two observation wells (F2 and F3) are present close (within 112 m) to the detailed area of study for this region. Since the three wells are closely situated, two wells, namely injection well F1 and the furthest observation well F3, have been focused on to monitor CO₂ movement. Time-lapse (pre- and post-injection) log, core and surface seismic data are used in the quantitative assessment of CO₂ saturation from the PDEM theory. It has been found that after approximately 9 months of injection, average CO₂ saturations in F1 and F3 are estimated as 50% in a zone of thickness ~ 25 m at a depth of ~ 3 km.  相似文献   

Ultrasonic attenuation of pure tetrahydrofuran hydrate          下载免费PDF全文

Mathias Pohl  Manika Prasad  Michael L. Batzle 《Geophysical Prospecting》2018,66(7):1349-1357

Improved estimates of the amount of subsurface gas hydrates are needed for natural resource, geohazard, and climate impact assessments. To evaluate gas hydrate saturation from seismic methods, the properties of pure gas hydrates need to be known. Whereas the properties of sediments, specifically sands, and hydrate‐bearing sediments are well studied, the properties of pure hydrates are largely unknown. Hence, we present laboratory ultrasonic P‐wave velocity and attenuation measurements on pure tetrahydrofuran hydrates as they form with reducing temperatures from 25°C to 1°C under atmospheric pressure conditions. Tetrahydrofuran hydrates, with structure II symmetry, are considered as proxies for the structure I methane hydrates because both have similar effects on elastic properties of hydrate‐bearing sediments. We find that although velocity increased, the waveform frequency content and amplitude decreased after the hydrate formation reaction was complete, indicating an increase in P‐wave attenuation after hydrate formation. When the tetrahydrofuran hydrate was cooled below the freezing point of water, velocity and quality factor increased. Nuclear Magnetic Resonance results indicate the presence of water in the “pure hydrate” samples above the water freezing point, but none below. The presence of liquid water between hydrate grains most likely causes heightened attenuation in tetrahydrofuran hydrates above the freezing point of water. In naturally occurring hydrates, a similarly high attenuation might relate to the presence of water.  相似文献   

Natural resource conditions and economic development in the Uttaranchal Himalaya, India     

Vishwambhar Prasad Sati 《山地科学学报》2005,2(4):336-350

Uttaranchal is bestowed with numerous rivers, huge forest resources ranging from tropical to temperate, tourists＇ places, pilgrimages and feasible climatic conditions for growing fruits, vegetables, food grains, livestock rearing, tea garden practices, etc. The economic development, on the other hand, could not take place partly due to lack of modern technology with innovation in agricultural system and also unwillingness of the people towards using it. Furthermore, due to its harsh climatic conditions, rigorous terrain and distinct identity, as a part of Uttar Pradesh state, the development could not take place and today the state is believed to be one of the poorer states. Infrastructurally, this region is lagged behind due to its inaccessibility. The ideal geographical and agrarian conditions might be used evenly for the developmental processes. Ecologically, the whole region is socio-economic activities, fragile. The diverse harsh traditional beliefs and hard working potentials further change the entire scenario of the state. Only the need of the hours is to frame and implementation of the rational policies and planning for sustainable development of the state. What had appeared during the past, pertaining to the economic development, needs radical changes in policies, planning and beliefs. This paper aims to evaluate the present conditions of resources as a form of natural vegetation, agricultural crops, horticultural farming, herbs, tea garden practices, livestock rearing, hydropower projects and economic development of the Uttaranchal Himalaya.  相似文献