Holocene tectono-geomorphic evolution of Haryana plains,Western Ganga plain,India     

Pitambar Pati  Vivekanand Acharya  Aditya Kumar Verma  Narendra Kumar Patel  Rajendra Prasad Jakhmola  Chinmay Dash  Vijay Sharma  Ankit Gupta  Brahm Parkash  Arun Kumar Awasthi 《Arabian Journal of Geosciences》2018,11(13):361

Haryana plain is the drainage divide between the Ganga plain in the east and the Indus plain in the west. Being a part of the Himalayan foreland, its geomorphology, sedimentation processes, and tectonism are broadly controlled by the Himalayan tectonics. Soil and geomorphological mapping in Haryana plain bring out geomorphic features such as paleochannels, various active drainage patterns, and landforms such as old fluvial plains, floodplains, piedmonts, pediments, terminal fans, and eolian plains. Based on the degree of soil development, and Optical stimulated luminescence (OSL) ages, the soil-geomorphic units were grouped into six members (QIMS-I to VI) (Quaternary Indus Morphostratigraphic Sequence) of a morphostratigraphic sequence: QIMS-VI 9.86–5.38 Ka, QIMS-V 5.38–4.45 Ka, QIMS-IV 4.45–3.60 Ka, QIMS-III 3.60–2.91 Ka, QIMS-II <?2.91–1.52 Ka, and QIMS-I <?1.52 Ka. OSL chronology of different geomorphic features suggests six episodes of tectono-geomorphic evolution in the region since 10 Ka. Neotectonic features such as nine faults, two lineaments, and five fault-bounded tectonic blocks have been identified. Independent tilting and sagging of the blocks in response to neotectonics have resulted in modification of landforms, depositional processes, and hydro-geomorphology of the region. Major rivers like the Yamuna, the Ghaggar, and the Sutlej show different episodes of shifting of their courses. Lineament controlled few extinct channels have been recorded between 20 and 25 m depth below the surface in the ground-penetrating radar (GPR) profiles. These buried channels are aligned along the paleo-course of the Lost Saraswati River interpreted from the existing literature and hence are considered as the course of the lost river. Seven terminal fans have been formed on the downthrown blocks of the associated faults. The Markanda Terminal Fan, the first of such features described, is indeed a splay terminal fan and was formed by a splay distributary system of the Markanda River. Association of three terminal fans of different ages with the Karnal fault indicates the segment-wise development of the fault from west to east. Also, comparison with other such studies in the Ganga plain to further east suggests that the terminal fans formed by streams with distributary drainage pattern occur only in semiarid regions as in the present area and thus are indicators of semiarid climate/paleoclimate. Though the whole region is tectonically active, the region between the Rohtak fault and Hisar fault is most active at present signified by the concentration of earthquake epicenters.  相似文献   

Anisotropic Continuous-in-Scale Universal Multifractal Cascades: Simulation,Analysis and Correction Methods     

Arun Ramanathan  A. N. V. Satyanarayana  M. Mandal 《Mathematical Geosciences》2018,50(7):827-859

Continuous-in-scale multifractal cascades has long been an attractive choice for mathematically modeling turbulent and turbulent-like geophysical fields. These fields are usually anisotropic as they are subject to both stratification and rotation, thereby questioning the isotropy assumption often made to model them. The self-affine and generalized scale invariance approaches to scaling are used here to introduce anisotropy in such models. These anisotropic simulations have (1) unresolved large-scale features and (2) statistics that deviate from the desired power-law scaling mainly in the small scales. The former issue is solved via nesting, whereas the latter is attempted to be overcome using singularity correction methods. While earlier studies have proposed isotropic correction methods, here they have been generalized to correct anisotropic simulations. These singularity corrections seem to improve the small-scale statistical properties of mildly anisotropic simulations; nesting, on the other hand, appears to enhance statistics over almost all scales even for strongly anisotropic simulations. Both the correction and nesting techniques lead to a reduction in computational time and memory usage suggesting that nested singularity-corrected cascades offer a better framework for quantitatively modeling the atmosphere, ocean, solid earth, and associated fields.  相似文献   

A comparative study of soil erosion modelling by MMF,USLE and RUSLE   总被引：1，自引：0，他引：1  

Arun Mondal  Deepak Khare  Sananda Kundu 《国际地球制图》2018,33(1):89-103

The quantitative assessment of spatial soil erosion is valuable information to control the erosion. The study area in a part of Narmada river in central India is selected. The main objective is to assess and compare the results obtained from three soil erosion models using GIS platform. Variation in the rate of erosion of the three models is compared considering varying slope, soil and land use of the area. Three models selected are Morgan–Morgan–Finney (MMF), Universal Soil Loss Equation (USLE) and Revised Universal Soil Loss Equation (RUSLE). The best fit or the most reliable model for the study area is selected after validation with the observed sedimentation data. The results give –39.45%, –9.60% and 4.80% difference in the values of sedimentation by MMF, USLE and RUSLE, respectively, from the observed data. Finally, RUSLE model has been found to be most reliable for the study area.  相似文献   

Cool heads for a hot world – Social sciences under a changing sky     

Arun Agrawal  Maria Carmen Lemos  Ben Orlove  Jesse Ribot 《Global Environmental Change》2012,22(2):329-331

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Structural pattern in the Precambrian rocks of Sonua-Lotapahar region,North Singhbhum,eastern India     

Dhruba Mukhopadhyay  Tapas Bhattacharya  Tapan Chakraborty  Arun Kanti Dey 《Journal of Earth System Science》1990,99(2):249-268

In the western part of the North Singhbhum fold belt near Lotapahar and Sonua the remobilized basement block of Chakradharpur Gneiss is overlain by a metasedimentary assemblage consisting of quartz arenite, conglomerate, slate-phyllite, greywacke with volcanogenic material, volcaniclastic rocks and chert. The rock assemblage suggests an association of volcanism, turbidite deposition and debris flow in the basin. The grade of metamorphism is very low, the common metamorphic minerals being muscovite, chlorite, biotite and stilpnomelane. Three phases of deformation have affected the rocks. The principal D1 structure is a penetrative planar fabric, parallel to or at low angle to bedding. No D1 major fold is observed and the regional importance of this deformation is uncertain. The D2 deformation has given rise to a number of northerly plunging major folds on E-W axial planes. These have nearly reclined geometry and theL ₂lineation is mostly downdip on theS ₂surface, though some variation in pitch is observed. The morphology of D2 planar fabric varies from slaty cleavage/schistosity to crenulation cleavage and solution cleavage. D3 deformation is weak and has given rise to puckers and broad warps on schistosity and bedding. The D2 major folds south of Lotapahar are second order folds in the core of the Ongarbira syncline whose easterly closure is exposed east of the mapped area. Photogeological study suggests that the easterly and westerly closing folds together form a large synclinal sheath fold. There is a continuity of structures from north to south and no mylonite belt is present, though there is attenuation and disruption along the fold limbs. Therefore, the Singhbhum shear zone cannot be extended westwards in the present area. There is no evidence that in this area a discontinuity surface separates two orogenic belts of Archaean and Proterozoic age.  相似文献   

Instability due to time delay and its compensation in active control of structures     

Anil K. Agrawal  Yozo Fujino  Binod K. Bhartia 《地震工程与结构动力学》1993,22(3):211-224

Time delay problem and its compensation in active control of civil engineering structures were studied. It has been shown by stability analysis of a SDOF system with time delayed feedback that the maximum allowable time delay depends not only on the natural period of the structure but also on feedback gains. We have demonstrated by numerical simulation that the performance of the control system degrades significantly when the time delay is close to this value and it even becomes unstable when time delay is greater than or equal to this value. The maximum allowable time delay decreases with decrease in natural period of the structure as well as with increase in active damping. The paper presents a technique for compensation by modelling time delay as transportation lag. This method ensures the stability of the controlled system as well as the desired response reduction.  相似文献   

Comment on “Tectonic classification of basalts with classification trees” by Pieter Vermeesch (2006)     

Salil Agrawal 《Geochimica et cosmochimica acta》2007,71(13):3388-3390

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Palaeoclimatic inferences from the behaviour of radiocarbon dates of carbonates from Sand Dunes of Rajasthan     

R V Krishnamurthy  D P Agrawal  V N Misra  S N Rajaguru 《Journal of Earth System Science》1981,90(2):155-160

Radiocarbon dates on pedogenic CaCO₃, accumulated at various depths in a stabilised dune at Budha Pushkar, Rajasthan, show inversion with respect to ‘stratigraphy’. Occurrence of younger carbonates overlain by older ones at various levels, is interpreted in terms of a shift in climatic conditions causing pedogenic carbonates to be leached to greater depths. Based on this model, several wetter regions during the last 6000 years have been identified. The most significant shift from a dry to a wet phase seems to have taken place between 5000 and 4500 years ago. Conclusions drawn from this study is in agreement with that based on pollen data and extends this method as a potential palaeoclimatic indicator.  相似文献   

Planet Nine,dark matter and MOND     

C. Sivaram  Arun Kenath  O. V. Kiren 《Astrophysics and Space Science》2016,361(7):230

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Performance of large area x-ray proportional counters in a balloon experiment     

J. Roy  P. C. Agrawal  D. K. Dedhia  R. K. Manchanda  P. B. Shah  V. R. Chitnis  V. M. Gujar  J. V. Parmar  D. M. Pawar  V. B. Kurhade 《Experimental Astronomy》2016,42(2):249-270

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