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21.
ADAL SINGH BISHESHWAR D. BHARDWAJ ABUL H. M. AHMAD 《Boreas: An International Journal of Quaternary Research》1993,22(1):38-46
The Ganga basin provides a present-day example of a peripheral foreland basin. The course of the river is controlled by Himalayan tectonics. Three main types of architectural elements, such as channels (CH), sandy bedforms (SB) and overbank fines (OF) have been developed in Ganga River sediments. The channels (CH) include gravelly (Gs) and sandy channel (Ss) lithofacies. The sandy bedforms (SB) include trough cross-stratified (St), planar cross-stratified (Sp), horizontal stratified (Sh), sandy massive (Sm) and climbing ripple cross-laminated (Sr) lithofacies, all of which are active channel deposits. The overbank fines (OF) include massive silt and clay (Fm), parallel laminated silt and clay (FI) and climbing ripple cross-laminated (Sr) lithofacies. Mega units have been developed in the lower part of the active channel deposits, while small units have been developed in the upper part of active channel deposits, in inactive channel deposits and overbank fines. This study illustrates the seasonal and tectonic control on sedimentation. Petrofacies studies of the sediments indicate a recycled orogen provenance. The sediments are derived from rapidly uplifted fault blocks comprising granite, gneiss and basic and ultrabasic rocks. Lack of textural and compositional maturity suggests a local source of derivation. The principal control on sand composition is source lithology. The hot and humid climate may slightly increase the content of quartz in sand derived from reworked foreland basin sediments. but the effect is neither sufficient to shift the sand compositions out of the recycled orogen field nor does it obscure composition mixing patterns. 相似文献
22.
Atif AHMAD WANG Chao TANG Yixian Mubbashra SULTAN Attia FALAK DUAN Wei WANG Jing 《资源与生态学报(英文版)》2022,13(5):826-841
The judicious use and management of natural resources is vital to achieve sustainable development. Land and water are prime natural resources, and their depletion and degradation can lead to serious threats like land subsidence. Land subsidence is a phenomenon of the alteration of elevation at a point on the earth through the sinking of the surface. It occurs when the earth’s surface loses its support. The major causes of land subsidence include groundwater extraction, mining, construction overload, and other similar factors that increase pressure on the surface and eventually subsidize the land. Urban centers with excessive groundwater extraction and infrastructure development are at a high risk of subsidence. Lahore, the second-largest city in Pakistan, is undergoing an enormous increase in population density, uncontrolled urbanization with very large-scale construction projects, and intensive groundwater extraction which are responsible for subsidence directly or indirectly. Therefore, studies on groundwater status and unplanned urban appraisals have seriously urged monitoring of the subsidence in Lahore. Herein, we used freely available Sentinel-1 data for one year (from August 2018 to August 2019), with a high spatial and temporal resolution, to monitor subsidence in Lahore. The data were processed using the SNAP/StaMPS approach for Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) analysis, which is an advanced InSAR technique. The displacement velocity map from InSAR processing shows a significant land deformation in the area with values ranging from -114 to 15 mm yr-1. Along with the Sentinel-1 data, we also used supplementary data obtained from various government agencies of Pakistan to study the land cover map, transportation network and waterways of Lahore, soil types, population density, and field points for assessing the results and understanding the roles of various factors in the occurrence of uplift or subsidence. A strong correlation was established between subsidence and various parameters such as groundwater extraction and lowering of the water table, soil type variations, land cover changes, surface water channels, and population density. The deformation map confirms the greatest subsidence in the central part of Lahore, while the uplift is observed in the less populated and rural areas situated near Ravi River. The land subsidence and uplift could be attributed to groundwater extraction and recharge through the canal system and the river, respectively. 相似文献
23.
Sobia Ashraf Farhat Abbas Muhammad Ibrahim Umer Rashid Shoaib Khalid Hammad Raza Ahmad Khalid Rehman Hakeem Tahir Majeed 《地理学报(英文版)》2015,(2):225-235
Groundwater is the most appropriate and widely used source of drinking water,which is increasingly threatened by pollution from industrial and agricultural activities.To check the severity of the problem,156 groundwater samples were collected from various depths(60-110 ft) of 52 different localities in Faisalabad city,the third largest metropolis in Pakistan,and analyzed for the metals(Zn,Cu,Cd,Ni,Pb,Mn and Fe) concentration in 2009.Quantification was done by using Flame Atomic Absorption Spectrophotometer technique and the results were compared with WHO standards for drinking water quality.Results showed that the levels of Cu,Mn and Fe were below the WHO standards while the concentrations of Zn,Cd,Ni and Pb were above the recommended levels of safe drinking water.Correlation analysis among the occurrence of these heavy metals revealed a highly significant and positive correlation of Mn with Zn and Fe.A significant and positive correlation of Cd was also found with Cu and groundwater depth showing that there is strong association between Cu-Cd pair and that the Cd concentration varies with depth of groundwater in the study area.Regional patterns of heavy metals occurrence were mapped using Geographical Information System(GIS) for the identification and demarcation of risk areas.The concentration maps may be used by policymakers of the city to mitigate groundwater pollution. 相似文献
24.
Abstract The snow and rain in the Himalayas are the main sources of supply for the rivers in the Indo-Gangetic plains. Irrigation, hydropower generation, and water supply are very much dependent on the availability of water in the Himalaya rivers. Mathematical models serve as important aids for the estimation of water availability in rivers. In the present study the SLURP watershed model is applied to a rainfed area of the Satluj catchment located in the western Himalayas, India. The SLURP model developed at NHRI, Canada, is a distributed conceptual model which simulates the behaviour of a watershed by carrying out vertical water balances for each element of a matrix of landcovers and subareas of a watershed and then routing the resulting runoff between subareas. The ILWIS geographic information system was used to prepare the input data required for SLURP and land use data were obtained from the IRS satellite LISS II visible and near infrared sensors. The simulated flows at the Bhakhra Dam outlet of the Satluj catchment were computed and found to compare well with the observed flows. 相似文献
25.
Geospatial tools for assessing land degradation in Budgam district,Kashmir Himalaya,India 总被引:1,自引:0,他引:1
MEHNAZ RASHID MAHJOOR AHMAD LONE SHAKIL AHMAD ROMSHOO 《Journal of Earth System Science》2011,120(3):423-433
Land degradation reduces the ability of the land to perform many biophysical and chemical functions. The main aim of this
study was to determine the status of land degradation in the Budgam area of Kashmir Himalaya using remote sensing and geographic
information system. The satellite data together with other geospatial datasets were used to quantify different categories
of land degradation. The results were validated in the field and an accuracy of 85% was observed. Land use/land cover of the
study area was determined in order to know the effect of land use on the rate of land degradation. Normalized differential
vegetation index (NDVI) and slope of the area were determined using LANDSAT-enhanced thematic mapper plus (ETM+) data, advanced
space borne thermal emission and reflection radiometer, and digital elevation model along with other secondary data were analysed
to create various thematic maps, viz., land use/land cover, geology, NDVI and slopes used in modelling land degradation in
the Kashmir Himalayan region. The vegetation condition, elevation and land use/land cover information of the area were integrated
to assess the land degradation scenario in the area using the ArcGIS ‘Spatial Analyst Module’. The results reveal that about
13.19% of the study area has undergone moderate to high degradation, whereas about 44.12% of the area has undergone slight
degradation. 相似文献
26.
Journal of Earth System Science - The artificial recharge is a technique of aquifer conservation for land subsidence. But in this article, the phenomenon of land subsidence and the resulting cracks... 相似文献
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28.
Asghar ALI Khaista REHMAN Owais TAYYAB Tahir ZAMAN Mahad JAMEEL Azeem KHAN Rafique AHMAD Muhammad IRFAN 《《地质学报》英文版》2020,94(5):1440-1450
Analysis of the anomalous magnetic mineral intensities and geochemistry for placer gold deposits are presented for those of the Attock area at the confluence of the Indus and Kabul rivers in northwestern Pakistan. Two grids covering an area of 10x18 m2 and 8x10 m2 were analyzed using a G-858 Cesium Vapor Magnetometer. The anomalous zones obtained were plotted on contour maps, 2D and 3D magnetic intensity maps. Based on the magnetic anomalies, grid-1 of the study area was sampled at three different anomalous zones for geochemical analysis. These zones contain gold concentrations, ranging from 2.11 ppm to 6.109 ppm with an average of 4.01 ppm. Increase in gold concentration in the subsurface within the anomalous zones indicates that magnetometer survey followed by a geochemical analysis can potentially narrow down the gold-bearing anomalous zones. 相似文献