نتایج جستجو برای: fluvial environment

تعداد نتایج: 521898  

2015
Claire Cousins

The search for once-habitable locations on Mars is increasingly focused on environments dominated by fluvial and lacustrine processes, such as those investigated by the Mars Science Laboratory Curiosity rover. The availability of liquid water coupled with the potential longevity of such systems renders these localities prime targets for the future exploration of Martian biosignatures. Fluvial-l...

2013
J Bendix

In this chapter, we review the historical arc of research on biogeomorphic interactions between fluvial geomorphology and riparian vegetation. We then report on an examination of the past 20 years of published research on this topic. Having classified studies according to the key relationships they have identified, we map those relationships to seek spatial patterns that emerge in terms of eith...

2013
Rebecca M.E. Williams Devon M. Burr Tanya Harrison Phillip McClelland

In the largest known population of sinuous ridges on Mars, Aeolis Serpens stands out as the longest ( 500 km) feature in Aeolis Dorsa. The formation of this landform, whether from fluvial or glacio-fluvial processes, has been debated in the literature. Here we examine higher-resolution data and use a terrestrial analog (the Mirackina paleoriver, South Australia) to show that both the morphology...

2017
JANE K. HART Jane K. Hart

At Aberdaron, north Wales, a complex sequence of homogeneous tills and fluvial sediments overlie a hard rock base. The lower diamicton association at the bottom of the sequence consists of deformed tills and lenses of stratified sediments. It is suggested that these represent deforming bed tills and subglacial fluvial units which have been deformed together by subglacial excavational deformatio...

Journal: :Science 2014
J P Grotzinger D Y Sumner L C Kah K Stack S Gupta L Edgar D Rubin K Lewis J Schieber N Mangold R Milliken P G Conrad D DesMarais J Farmer K Siebach F Calef J Hurowitz S M McLennan D Ming D Vaniman J Crisp A Vasavada K S Edgett M Malin D Blake R Gellert P Mahaffy R C Wiens S Maurice J A Grant S Wilson R C Anderson L Beegle R Arvidson B Hallet R S Sletten M Rice J Bell J Griffes B Ehlmann R B Anderson T F Bristow W E Dietrich G Dromart J Eigenbrode A Fraeman C Hardgrove K Herkenhoff L Jandura G Kocurek S Lee L A Leshin R Leveille D Limonadi J Maki S McCloskey M Meyer M Minitti H Newsom D Oehler A Okon M Palucis T Parker S Rowland M Schmidt S Squyres A Steele E Stolper R Summons A Treiman R Williams A Yingst

The Curiosity rover discovered fine-grained sedimentary rocks, which are inferred to represent an ancient lake and preserve evidence of an environment that would have been suited to support a martian biosphere founded on chemolithoautotrophy. This aqueous environment was characterized by neutral pH, low salinity, and variable redox states of both iron and sulfur species. Carbon, hydrogen, oxyge...

2008
Edmundo C. Drago Karl M. Wantzen Aldo R. Paira

We report herein the first description of the physical structure of the aquatic habitats of the Lower Paraguay River along 390 km from Asunción city (Paraguay) to the confluence with the Paraná River. The hierarchical ordination of the Fluvial Hydrosystem Approach (FHA) allowed us to classify the Lower Paraguay as a meandering functional sector where five functional sets were identified: (a) ma...

2016
Kyle M. Straub Douglas J. Jerolmack David Mohrig Daniel H. Rothman

Fluvial drainage basin area is often related to channel length and local slope through power law relationships and the relatively small range of exponents observed in these relationships is thought to result from physical mechanisms. Proposed mechanisms assume that the observed correlation between drainage area and fluid discharge is caused by precipitation. Using high resolution DEMs of channe...

2009
Jason P. Field David D. Breshears Jeffrey J. Whicker

Soil erosion is driven by not only aeolian but also fluvial transport processes, yet these two types of processes are usually studied independently, thereby precluding effective assessment of overall erosion, potential interactions between the two drivers, and their relative sensitivities to projected changes in climate and land use. Here we provide a perspective that aeolian and fluvial transp...

2009
Geoffrey C. Collins

[1] Observations of likely fluvial channels on the surface of Titan, along with Titan’s geologically youthful surface, motivate this study of comparative fluvial erosion rates on Titan and the Earth. The roles of bedload abrasion, suspended load abrasion, plucking, and cavitation are considered. Despite orders of magnitude differences in some of the physical parameters that control fluvial inci...

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