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151.
In order to check the premature siltation of the reservoirs and guard against the drop in the irrigation potential, the Government of India has launched the schemes of soil conservation and integrated watershed management in the catchments of RVPs and Flood Prone rivers. Owing to the large financial and manpower commitments needed to implement and execute soil conservation measures over vast catchment areas, a priority approach for treatment was identified. The methodology developed for prioritization of watersheds of a catchment area conceptualizes sedimentation of the reservoirs as a multiplicative function of erosivity value and the delivery ratio. This paper deals with the development of a computerized data base software module ‘WEIGHT’ for determination of erosivity values for the mapping units comprising assemblages of the varying combinations of climate, physiography and slope, land use and cover conditions, soil characteristics (texture, solumn thickness, permeability and pH) and the existing erosion and soil conservation measures. The WEIGHT software package is coded in FORTRON-4 for PDP 11/83 operating system. the data base comprises storage of the attributes of the different erosivity determinants of the mapping units with predetermined erosivity values sequentially on a disk and comparing the attributes of a new mapping unit to get the most probabilities erosivity value. The objective has been to eliminate the personal bias and bring about the objectivity in the process of assigning erosivity values to the different mapping units. The data base design, design logic and operational sequence of the data base are discussed in the paper.  相似文献   
152.
Gold deposits and occurrences small in reserves and high in Au grade conventionally determine the line of prospecting in terrigenous sequences of the Verkhoyansk–Kolyma region. In this paper, the geological structure of such gold objects is considered with the example of the deposits and prospects making up the Zhdaninsky ore–placer cluster in the Republic of Sakha (Yakuia). From lithological, structural, and mineralogical–geochemical data, the formation conditions of ore-bearing complexes are specified, the geological evolution history of the northern Ol’chan Zone of the Kular–Nera Belt is reconstructed, and the zonal distribution of mineralization within the ore–placer cluster is revealed. The structural–compositional complexes were formed in the following succession: (1) sedimentation at the shelf of the passive margin accompanied by synsedimentation deformations; (2) metagenesis of sediments and the development of bedding-plane intraformational detachments of collision stage D1 under conditions of tangential compression and accompanied by the formation of carbon dioxide–aqueous metamorphic fluid at a temperature of 300°C and under a pressure of 1.4 kbar; (3) folding and faulting of orogenic stage D2 with the formation of synkinematic magmatic bodies, metasomatic alteration, and Au-bearig mineral assemblages. Small Au-bearing objects with veined mineralization and high Au grade are localized in structures of stage D2 transverse to bedding-plane schistosity S1. They form at the collision stage above intraformational detachment surfaces and are controlled by shear structures of the orogenic stage with misalignment of these deformations. The ore zoning is determined by the distribution of Co and Ni minerals and by variations in the anionic composition of ore (S, As, Sb).  相似文献   
153.
The composition and nature of high-Cr minerals in lithic clasts from the carbonatites of the Veseloe occurrence, northern Transbaikalia, were considered. In order to determine their source, the Cr-bearing phases were compared with chromite, magnetite, and rutile from ultrabasic rocks, mantle xenoliths, and eclogites. It was suggested that the xenoclasts studied were formed at great depths, whereas the carbonatites were directly derived from the mantle rather than formed by the crustal differentiation of a silicate-carbonate melt.  相似文献   
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Sattar  Ashim  Goswami  Ajanta  Kulkarni  Anil V. 《Natural Hazards》2019,98(2):817-817
Natural Hazards - The article was published with the citation “Worni et al. (2012)”. The author group of the article would like readers to know that this information should instead...  相似文献   
157.
This paper presents an integrated measurement technique based on DC methods (vertical electrical sounding, electrical resistivity tomography) which was used to identify faults and determine their geoelectric parameters in the western part of the Chuya basin. New information on the structure of the Chagan River valley located in the zone of the disastrous 27 September 2003 Chuya earthquake has been obtained from the results of these methods. Geoelectric cross-sections of the sedimentary sequence and the upper part of the basement were obtained from VES data, showing the block structure of the study area. Electrical resistivity tomography sections confirm the presence of a major fault between basement blocks of different heights and indicate the presence of faults bounding the valley on its right side and in the southwestern part.  相似文献   
158.
This work is based on the results of 2-D and 3-D surveys in the Tuapse Basin and field works in the Crimea-Caucasus region. Seven zones were outlined in the model of sedimentation starting from the eroded mountain structure of the Greater Caucasus down to deep water sediments of the Tuapse Basin. The slope and deep-water sediments of channels and fan complexes are characterized. Volume models of the sedimentation system in the Black Sea are shown for the first time.  相似文献   
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Current and future wide field surveys in infrared passbands present opportunities for ultra low‐mass stellar sample selection via proper motions, as well as or instead of purely photometric techniques. Furthermore, proper motion measurements yield additional clues as to candidate membership of cluster or field (kinematic) populations. In this paper we review some recent results and speculate as to the possibilities afforded by the next generation of wide‐field infrared surveys. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   
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