596 resultados para 260114 Geomorphology


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The Humphreys Quadrangle is a portion of the easternmost Ventura Basin underlain by a thick series of Tertiary sedimentary rocks. On these rocks a great variety of geomorphic forms have been molded by the processes of running water typical of a semi-arid climate and by several types of mass movement. Among the different categories of mass movement present, a new type, the siltflow, was observed.

The geomorphic forms of special interest present in the quadrangle are rock cones, open canyonheads, asymmetric canyons, and stream terraces and straths. The author urges the adoption of the definition of strath as that part of an old dissected valley floor, including the floors of tributary valleys, which was not part of the floodplain of the main valley stream.

An old erosion surface, the Puckett Mesa Surface, is present in the Humphreys Quadrangle which is correlative with certain of the older stream terraces. By correlating the variation of gradient and of fill of the stream terraces with post –Wisconsin climatic fluctuations the age of the Puckett Mesa Surface is set at approximately 6000 B.C. This correlation sets the probable age of the older Rancho La Brea deposits at 6000 to 8000 B. C. and the probable age of the Carpenteria brea deposits at 1000 to 1 B. C.

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This is the Fluvial Geomorphology Report produced by the National Rivers Authority (NRA) in 1994. The purpose of this paper is to briefly outline the relevance of fluvial geomorphology and the substantial benefits which could accrue from applying it nationally across the NRA. It compliments information given in a previous paper dated 27 October 1993 which was presented to a national FRCN meeting on 9 March 1994.

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This is the River Eden RHS and geomorphology evaluation: Final report October 2001 produced by the Environment Agency North West in 2001. This report analysed the River Habitat Survey (RHS) and geomorphology data to evaluate the level of habitat quality and the geomorphological characteristics of the River Eden and sub-catchments. RHS data and geomorphological assessment data was collected within the study areas by CEH and Fluvial Environmental Services Ltd. The River Eden and its sub-catchments are being considered as a Special Area for Conservation (SAC) due to the presence of habitat types and species, which are rare or threatened within Europe. The purpose of the project is to provide an overview of the state of the catchment in terms of river habitats and geomorphological processes in order to aid the derivation of sound management for this proposed SAC.The aim of this report was to determine the state of the environment within the Eden and sub-catchments and identify the main pressures on the system in order to derive sound management options.

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The Lasbela coast formulates the southeastern part of Balochistan province. The plain area in the north of the coast is a triangular shaped valley bounded by mountains on both of its flanks called as the Lasbela plain.

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National Natural Science Foundation of China [40871177]; Project of State Key Lab of Resources and Environmental Information System [088RA304SA]; CAS Knowledge Innovation Project

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The Zenisu deep-sea channel originates on the Izu-Ogasawara island arc, and disappears in the Shikoku Basin of the Philippine Sea. The geomorphology, sedimentary processes, and the development of the Zenisu deep-sea channel were investigated on the basis of swath bathymetry, side-scan sonar imagery, submersible observations, and seismic data. The deep-sea channel can be divided into three segments according to the downslope gradient and channel orientation. They are the Zenisu Canyon, the E-W fan channel, and the trough-axis channel. The sediment fill is characterized by turbidite and debrite deposition and blocky-hummocky avalanche deposits on the flanks of the Zenisu Ridge. In the Zenisu Canyon and the Zenisu deep-sea channel, sediment transport by turbidity currents generates sediment waves (dunes) observed during the Shinkai 6500 dive 371. The development of the Zenisu Canyon is controlled by a N-S shear fault, whereas the trough-axis channel is controlled by basin subsidence associated with the Zenisu Ridge. The E-W fan channel was probably affected by the E-W fault and the basement morphology.

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