نتایج جستجو برای: alluvial river

تعداد نتایج: 86183  

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 ...

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 ...

Aims & Backgrounds: The Quaternary period is considered as the interval of climatic oscillations (glacial and interglacial) coupled with tectonic episodes. Therefore, tectonics and climate have simultaneously governed the evolution of Quaternary alluvial fans. Unraveling the tectonic and climatic factors under varied depositional systems is therefore the fundamental issue in understanding the e...

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: :Tree physiology 2003
Stewart B Rood Jeffrey H Braatne Francine M R Hughes

Cottonwoods (Populus spp.) are adapted to riparian or floodplain zones throughout the Northern Hemisphere; they are also used as parents for fast-growing hybrid poplars. We review recent ecophysiological studies of the native cottonwoods Populus angustifolia James, P. balsamifera L., P. deltoides Marsh., P. fremontii S. Watson and P. trichocarpa T. & G. in North America, and P. nigra L. in Euro...

Journal: :Brazilian journal of biology = Revista brasleira de biologia 2015
M Camargo T Giarrizzo A J S Jesus

The assumption for this study was that litterfall in floodplain environments of the middle Xingu river follows a pattern of seasonal variation. According to this view, litterfall production (total and fractions) was estimated in four alluvial rainforest sites on the middle Xingu River over an annual cycle, and examined the effect of seasonal flooding cycle. The sites included two marginal flood...

2016
Colin B Phillips Douglas J. Jerolmack

Understanding the mechanics of bed load at the flood scale is necessary to link hydrology to landscape evolution. Here we report on observations of the transport of coarse sediment tracer particles in a cobblebedded alluvial river and a step-pool bedrock tributary, at the individual flood and multi-annual timescales. Tracer particle data for each survey are composed of measured displacement len...

Journal: :تحقیقات جغرافیایی 0
منصور سعیدی کیا گروه جغرافیا دانشگاه رازی کرمانشاه محمود علائی طالقانی گروه جغرافیا دانشگاه رازی کرمانشاه

abstract: in this research, the relationship between geomorphologic factors with underground water resources in zahab plain (in west of kermanshah) has been analyzed using by analyzing-deducing and weighting methods. first, by using of pizometeric and exploratory well data, variation of water table in zahab plain has been comparative analysis with geomorphic unites and then, the zahab watershed...

2007
Fabio Florindo Daniel B. Karner Fabrizio Marra Paul R. Renne Andrew P. Roberts Richard Weaver

Buried sedimentary aggradational sections deposited between 800 ka and 600 ka in the Tiber River coastal alluvial plain have been studied using borecores from around Rome. Ar/Ar ages on sanidine and/or leucite from intercalated tephra layers and paleomagnetic investigation of clay sections provide geochronologic constraints on the timing of aggradation of two alluvial sections, demonstrating th...

2016
Rachel L. Malison Kirill V. Kuzishchin Jack A. Stanford

Beaver have expanded in their native habitats throughout the northern hemisphere in recent decades following reductions in trapping and reintroduction efforts. Beaver have the potential to strongly influence salmon populations in the side channels of large alluvial rivers by building dams that create pond complexes. Pond habitat may improve salmon productivity or the presence of dams may reduce...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید