نتایج جستجو برای: fluvial

تعداد نتایج: 4448  

2017
William I. Ford James F. Fox

Watershed-scale carbon budgets remain poorly understood, in part due to inadequate simulation tools to assess in-stream carbon fate and transport. A new numerical model termed ISOtope-based FLuvial Organic Carbon (ISOFLOC) is formulated to simulate the fluvial organic carbon budget in watersheds where hydrologic, sediment transport, and biogeochemical processes are coupled to control benthic an...

2017
Zhijun Gong Sheng-Hua Li Bo Li

The Tian Shan range lies in the actively deforming part of the India-Asia collision zone. The uplift rate and deformation pattern of the Tian Shan are important for understanding the dynamics of crustal deformation in the region. The river terraces in northern Tian Shan provide key records of past changes in climate and/or regional tectonics. In this study, a terrace sequence along the Manas Ri...

2007
John A. Grant

Interpretation of ground penetrating radar data from the 3.7 Ma old Roter Kamm impact crater, together with results of petrographic and sedimentologic analysis of sediment samples, indicates that --40 m or more of slope sensitive degradation f the rim was accompanied by reduction of wall slopes well below the angle of repose and nearly complete rosion of ejecta ,urn •uuu,u the crater. •,my u.c ...

2014
Antoine Lucas Oded Aharonson Charles Deledalle Alexander G. Hayes Randolph Kirk

The Cassini Synthetic Aperture Radar has been acquiring images of Titan’s surface since October 2004. To date, 59% of Titan’s surface has been imaged by radar, with significant regions imaged more than once. Radar data suffer from speckle noise hindering interpretation of small-scale features and comparison of reimaged regions for change detection. We present here a new image analysis technique...

2015
C. Skonieczny P. Paillou A. Bory G. Bayon L. Biscara X. Crosta F. Eynaud B. Malaizé M. Revel N. Aleman J. -P. Barusseau R. Vernet S. Lopez F. Grousset

The Sahara experienced several humid episodes during the late Quaternary, associated with the development of vast fluvial networks and enhanced freshwater delivery to the surrounding ocean margins. In particular, marine sediment records off Western Sahara indicate deposition of river-borne material at those times, implying sustained fluvial discharges along the West African margin. Today, howev...

2010
M. A. RUSSELL D. E. WALLING R. A. HODGKINSON

Geochemical analysis of suspended sediment is a key requirement in nutrient and contaminant transfer studies, but the collection of fluvial suspended sediment samples is problematic due to the highly episodic nature of its transport. Traditional approaches involve the collection of instantaneous samples, but uncertainties regarding intraand inter-storm variations in sedi­ ment-associated nutrie...

2017
Menno W Straatsma Alexandra M Bloecker H J Rob Lenders Rob S E W Leuven Maarten G Kleinhans

Biodiversity declined markedly over the past 150 years, with the biodiversity loss in fluvial ecosystems exceeding the global average. River restoration now aims at flood safety while enhancing biodiversity and has had success locally. However, at the scale of large river distributaries, the recovery remained elusive. We quantify changes in biodiversity of protected and endangered species over ...

2011
Ribeiro Filho

Reservoirs are manmade habitats, intermediate between rivers and lakes, presenting distinct hydrological and morphometric characteristics, with differential mean water residence time. They also present proper vertical and horizontal organisations, and their evolution depends on several variables acting on different special and temporal scales. The water quality evolution of the Itaipu Reservoir...

2014
Elena R. Schroeter Victoria M. Egerton Lucio M. Ibiricu Kenneth J. Lacovara

Here we report multiple lamniform shark teeth recovered from fluvial sediments in the (Campanian-Maastrichtian) Cerro Fortaleza Formation, Santa Cruz Province, Argentina. This small tooth assemblage is compared to various lamniform sharks possessing similar dental morphologies, including Archaeolamna, Cretalamna, Dwardius, Dallasiella, and Cretodus. Although the teeth share numerous morphologic...

2009
N. Schiavon

The chemicalmineralogical composition of the sand fractions of mortars found in Roman villas dating from the 1 st century A.C. located in Northern Italy has been investigated by optical microscopy, scanning electron microscopy plus energy dispersive spectroscopy microanalysis and x-ray diffractometry. The petrographic results on the mortar samples have been compared with mineralogical data avai...

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