نتایج جستجو برای: alluvial fans

تعداد نتایج: 7388  

2005
Jeffrey M. Moore Alan D. Howard

[1] Several dozen distinct alluvial fans, 10 to 40 km long downslope, have been observed in highlands craters. Within a search region between 0 and 30 S, alluvial fan-containing craters were found only between 18 and 29 S, and they all occur at around ±1 km of the MOLA-defined Martian datum. Within the study area they are not randomly distributed but instead form three distinct clusters. Fans t...

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...

2007
A. M. HARVEY

This volume presents a series of papers on the geomorphology, sedimentology and dynamics of alluvial fans, selected from those presented at the 'Alluvial Fans' Conference held in Sorbas, SE Spain in June 2003. The conference was sponsored primarily by the British Geomorphological Research Group and the British Sedimentological Research Group, both organizations affiliated to the Geological Soci...

Journal: :جغرافیا و مخاطرات محیطی 0
عقیل مددی داود مختاری حمدیه شیرزادی ارسلان مهرورز

1. introduction the earth's crust is composed of various landforms. these forms are constantly changing. in this change, both of internal and external factors have a decisive role. the internal factors led to the formation of the primary structure and external factors that cause erosion, deformation and destruction of these forms. areas that have been affected by these activities confronted by ...

2004
Demetre P. Argialas Angelos Tzotsos

There is a need to automate terrain feature mapping so that to make the process more objective and less time consuming by using proper feature extraction techniques. The objective of this study was the use of object-oriented image analysis methods for the automatic extraction of alluvial fan terrain units. The study area was located in the Death Valley, Nevada, USA. The data used included an AS...

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Darab Plain is among region that in there formed several alluvial fans because presence of situation and climate change, and can mention to Katoeh, Rigabad and Chenar alluvial fans. In this research is tried to using of Geology and Topographic Maps, Arial Image ana Field survey analysis are discussed  Factors affecting the establishment and evolution of this alluvial fans. Result showed that Ka...

2009
C. J. Hardgrove J. E. Moersch S. C. Whisner

Introduction: We have previously demonstrated the viability of using thermal infrared images for mapping surface grain size distributions on terrestrial allu-vial fans [1, 2, 3]. For a well characterized alluvial fan in Owens Valley, CA we have used a quantitative analysis between aerial thermal images and ground-based grain size counts as well as a qualitative analysis between our thermal imag...

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...

This research focuses on alluvial fans in desert area. Alluvial fans are one of the most important geomorphological units in desert area. There are several tremendous methods to separate alluvial fans. There are qualitative and quantitative factors to differentiate them from other geomorphological units. In this study effective geomorphometrical parameters in differentiate landforms were applie...

1997
L. A. OWEN

Alluvial fans in southern Monglia occur along a group of narrow discontinuous mountain ranges which formed as transpressional uplifts along a series of strike-slip faults. They provide information on the nature of neotectonic activity in the eastern Gobi Altai range and on palaeoclimate change. Alluvial fan formation was dominated by various geomorphological processes largely controlled by clim...

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