نتایج جستجو برای: alluvial fan

تعداد نتایج: 15294  

Journal: :تحقیقات جغرافیایی 0
داود مختاری دانشگاه تبریز داود مختاری دانشگاه تبریز

â â â  parsian alluvial fan system is a part of asyab-kharabeh fluvial system that response it to quaternary climate changes is the main goal of this study. for this aim, climatic proxies and traces in alluvial fan structure were investigated base d o n four categories: aggradation and degradation phases, debris flows, size changes in deposited materials and formation of alluvial fan tufas. pri...

Journal: :تحقیقات جغرافیایی 0
علیرضا تقیان دانشگاه اصفهان

abstract alluvial fans are the most striking phenomena o fluvial geomorphology . these forms are found in frount of mountains and pediments of arid and semiarid zones . alluvial fans are affected by climate changes and tectonics . occurring of tectonic events lead to reaction of alluvial fans . some of these reactions appear on dissection of alluvial fans and displacement of depocenters on allu...

ژورنال: کواترنری ایران 2019
Berensmeier, 6. Michaelela , Jahani, Davood , Lak, 3. Razyeh , Mohammadi Vizhe , Mehdi , Nazary, Hamid , Pashazadeh, Behnam ,

Abstract: Alluvial fan are one of the most dynamic Quaternary landforms in arid areas.An alluvial fan in the southeast of the city Yazd was identified based on satellite images; in this research, the primary objective of this study is to investigate the surface and subsurface sedimentology of alluvial fan flasks. Twenty soil samples were taken for sedimentological studies. The result indicate ...

Journal: :پژوهش های جغرافیای طبیعی 0
عادل سپهر استادیار ژئومورفولوژی، دانشکدة منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد زهرا عبدالله زاده دانشجوی کارشناسی ارشد مهندسی منابع طبیعی، مدیریت مناطق بیابانی، دانشگاه فردوسی مشهد

introduction alluvial fans are depositional landforms developed on a confined channel emerged from a drainage basin, i.e. between a mountain range and a plain. an alluvial fan is a fan- or cone-shaped deposit of sediments crossed and built up by streams. if a fan is built up by debris flows, it is properly called a debris cone or colluvial fan. these flows come from a single point source at the...

2017
Qiaona Guo Shan Wang

Major ions and selected environmental tracers (D, 18O, 3H and chlorofluorocarbons (CFCs)) were employed to determine the source, flow rates, and hydrochemical evolution of groundwater in an alluvial fan along the front of the Qilian Mountains, which serves as an important groundwater reservoir in northwest China. Temporal and spatial variations in ion concentrations were limited near the upper ...

2011
John J. Armitage Nicholas H. Warner Kate Goddard Sanjeev Gupta

[1] Dozens of large, low‐gradient alluvial fans are present within impact crater basins on the cratered highlands of Mars. The timescales and climate conditions that were required to generate such fans are unknown, but testable through our understanding of terrestrial hill slope erosion in the presence of precipitation. Previous estimates of fan formation time vary from years to millions of yea...

2017
Luca C. Malatesta Michael P. Lamb

Waterfalls commonly exist near bounding faults of mountain ranges, where erosional bedrock catchments transition to depositional alluvial fans. We hypothesize that aggradation on alluvial fans can bury active faults, and that the faults accumulate slip in the subsurface to produce a bedrock scarp. Following entrenchment of the alluvial fan, the scarp can be exposed as a waterfall. To explore th...

2008
M. Cavalli L. Marchi

Alluvial fans of alpine torrents are both natural deposition areas for sediment discharged by floods and debris flows, and preferred sites for agriculture and settlements. Hazard assessment on alluvial fans depends on proper identification of flow processes and their potential intensity. This study used LiDAR data to examine the morphology of the alluvial fan of a small alpine stream (Moscardo ...

Journal: :Remote Sensing 2013
Lu Zhang Huadong Guo

Alluvial fans in arid and semi-arid regions can provide important evidence of geomorphic and climatic changes, which reveal the evolution of the regional tectonic activity and environment. Synthetic aperture radar (SAR) remote sensing technology, which is sensitive to geomorphic features, plays an important role in quickly mapping alluvial fan units of different ages. In this paper, RADARSAT-2 ...

2010
Nicholas Swanson-Hysell David L. Barbeau

Alluvial-fan strata contain valuable proxy data for kinematic, climatic and sediment-flux phenomena associated with high-relief source regions. Proper application of this data is dependent upon acquisition of accurate high-resolution chronostratigraphic data, best achieved through magnetostratigraphy. Collection of magnetostratigraphic and other proxy data from composite alluvial-fan sections a...

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