نتایج جستجو برای: alluvial river

تعداد نتایج: 86183  

2012
Cassandra R. Fenton Jon D. Pelletier

a r t i c l e i n f o Keywords: Colorado River basalt cosmogenic 3 He surface exposure ages climate change desert pavement desert alluvial fans southwest USA geomorphology Plio-Pleistocene deposits of the Lower Colorado River (LCR) and tributary alluvial fans emanating from the Black Mountains near Golden Shores, Arizona record six cycles of Late Cenozoic aggradation and incision of the LCR and...

ژورنال: کواترنری ایران 2019
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Introduction In theory, the bulk composition of the sediment may provide a way of determining the provenance of this material if there is sufficient diversity in the bedrock compositions. However, sediment compositions may be changed from the original bedrock as a result of transport and chemical weathering. The geochemistry of bedload and suspended sediments has been used by many workers to d...

2006
Sam VanLaningham Andrew Meigs Chris Goldfinger

Relationships between riverbed morphology, concavity, rock type and rock uplift rate are examined to independently unravel the contribution of along-strike variations in lithology and rates of vertical deformation to the topographic relief of the Oregon coastal mountains. Lithologic control on river profile form is reflected by convexities and knickpoints in a number of longitudinal profiles an...

1996
T. B. Liverpool S. F. Edwards

We present a statistical model of a meandering river on an alluvial plane which is motivated by the physical non-linear dynamics of the river channel migration and by describing heterogeneity of the terrain by noise. We study the dynamics analytically and numerically. The motion of the river channel is unstable and we show that by inclusion of the formation of ox-bow lakes, the system may be st...

2008
G. Vezzoli

In order to obtain a high-resolution Pleistocene stratigraphy, eleven continuously cored boreholes, 100 to 220m deep were drilled in the northern part of the Po Plain by Regione Lombardia in the last five years. Quantitative provenance analysis (QPA, Weltje and von Eynatten, 2004) of Pleistocene sands was carried out by using multivariate statistical analysis (principal component analysis, PCA,...

Journal: :Computers & Geosciences 2009
G. Gallerini Mauro De Donatis

In specific geological contexts, such as alluvial environments, the lithology is highly heterogeneous and laterally variable. As a result, a large number of lithological data are collected (generally random and under sampled) for stratigraphic reconstruction. The integrated management of geo-lithologic data causes major methodological problems, because data obtained from geognostic investigatio...

Journal: :مطالعات باستان شناسی 0
مهران مقصودی دانشیار گروه جغرافیای طبیعی، دانشگاه تهران سید محمد زمان زاده استادیار گروه جغرافیای طبیعی، دانشگاه تهران حسن فاضلی نشلی دانشیار گروه باستان شناسی، دانشگاه تهران روح الله یوسفی زُشک استادیار گروه باستان شناسی، دانشگاه آزاد ورامین سمیرا چزغه دانشجوی دکتری ژئومورفولوژی، دانشگاه شهید بهشتی حجت الله احمدپور دانش آموخته کارشناسی ارشد باستان شناسی، دانشگاه آزاد اسلامی واحد تهران مرکز

water resources throughout human history have always been an important factor in attracting human settlement. the main purpose of this paper was to investigate what is the role of shadchay river in the location of two prehistoric settlements that are called tepe meymon abad. in this research by field studies and also to investigate the characteristics of the sediments, samples were taken from t...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2012
T J Coulthard M J Van de Wiel

Over the last few decades, a suite of numerical models has been developed for studying river history and evolution that is almost as diverse as the subject of river history itself. A distinction can be made between landscape evolution models (LEMs), alluvial architecture models, meander models, cellular models and computational fluid dynamics models. Although these models share some similaritie...

2017
Andrew Brooks John Spencer Jon Knight

Alluvial gully erosion is a likely key sediment source into many large rivers in tropical Australia. This type of gullying differs fundamentally to the generally accepted gully model from Southern Australia, in that it is found exclusively within alluvium and can propagate entirely as a result of basal sapping. The process is found to varying degrees within alluvial river types along most Gulf ...

2007
Gokmen Tayfur Vijay P. Singh

[1] Transient bed profiles in alluvial channels are generally modeled using diffusion (or dynamic) waves and assuming equilibrium between detachment and deposition rates. Equilibrium sediment transport can be considerably affected by an excess (or deficiency) of sediment supply due to mostly flows during flash floods or floods resulting from dam break or dike failure. In such situations the sed...

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