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1. |
Floodplain sedimentation: Quantities, patterns and processes |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 481-499
Nathalie E. M. Asselman,
Hans Middelkoop,
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摘要:
AbstractThis paper presents the result of measurements of floodplain sedimentation using sediment traps. The study was carried out on two embanked floodplains along the Rivers Rhine and Meuse in The Netherlands during a 3 day flood in January 1993. Raster maps of sediment accumulation were made by interpolating the measurements from the traps using block kriging. The sediment maps show clear patterns in sediment accumulation, together with the estimated interpolation errors. Average sediment accumulation ranges between 0·57 and 1·0 kg m−2. High sediment accumulation is found on the levees (4 kg m−2or more) and on low lying areas (1·6 kg m−2); sediment accumulation decreases with distance from the main channel. The sedimentation patterns are related to floodplain topography and sediment transporting mechanisms. Sediment transport by turbulent diffusion as well as by convection can be recognized. Also, flood duration and the process of sediment settling out in ponding water in closed depressions are important. The applied method allows comparison of the results with raster‐based sedimentat
ISSN:0197-9337
DOI:10.1002/esp.3290200602
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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2. |
Limestone weathering in Eastern Australia. Part 2: Surface micromorphology study |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 501-514
C. Moses,
A. P. Spate,
D. I. Smith,
M. A. Greenaway,
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摘要:
AbstractResults from long term microerosion meter (MEM) studies indicate that microenvironments are characterized by different erosion rates. A complementary study, carried out on the same sites, examines the microscale morphology in each environment. Optical and scanning electron microscopy were used to identify a range of features thought to reflect different processes.Under subaerial conditions micromorphology is dominated by biological weathering features owing to the presence of microflora. Sites permanently covered by soil or stream water have only dissolution etch features, though stream sites may exhibit microfractures. Sites with periodic exposure exhibit both dissolution and biological etch features. The natural environment is more accurately reflected by allowing some microflora colonization of MEM sites rather than preventing colonization by artificial means.
ISSN:0197-9337
DOI:10.1002/esp.3290200603
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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3. |
Dune mobility and vegetation cover in the Southwest Kalahari desert |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 515-529
Giles F. S. Wiggs,
David S. G. Thomas,
Joanna E. Bullard,
Ian Livingstone,
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摘要:
AbstractAs part of a wider project investigating the palaeoenvironmental significance of partially vegetated linear dunes in the southwest Kalahari, data collected in the latter part of 1992 concerning dune movement and vegetation cover suggest that sediment transport is occurring on some dune surfaces, and that the majority of surface activity occurs on the crests and upper slopes of the dunes. The data suggest that the limiting variables on surface sediment movement vary on different parts of a dune. On interdunes and lower dune slopes the primary limiting variable is available wind energy, while on dune crests and upper slopes it is vegetation cover. Ground cover by litter has much greater importance in protecting the surface sediment from erosion than rooted vegetation. From individual data points, no evidence is found to support a threshold vegetation cover below which sediment movement occurs. Rather, a gradient of activity is suggested whereby a reduction in vegetation cover increases the potential for sediment movement and surface change. However, dunes with differing amounts of mean vegetation cover display differing degrees of surface activity, and at this scale, a vegetation cover threshold in the region of 14 per cent may be recognized.
ISSN:0197-9337
DOI:10.1002/esp.3290200604
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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4. |
Using gravestones to assess changing rates of weathering in the United Kingdom |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 531-546
R. U. Cooke,
R. J. Inkpen,
G. F. S. Wiggs,
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摘要:
AbstractWeathering rates were calculated using the height difference between lead lettering and marble on gravestones at three sites in the UK. Comparison of their regression lines and residuals suggested that two of the sites, Portsmouth and Wolverhampton, had similar amounts and rates of weathering over the last 100‐150 years. Gravestones in Swansea appear to have weathered much more and much faster than gravestones at the other two sites. These differences may be the result of the differing pollution and rainfall histories of the three site
ISSN:0197-9337
DOI:10.1002/esp.3290200605
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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5. |
Rapid formation of rock varnish and other rock coatings on slag deposits near Fontana, California |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 547-560
Ronald I. Dorn,
Norman Meek,
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摘要:
AbstractManganiferous rock varnish, silica glaze and iron skins have formed on 20‐ to 40‐year‐old slag piles near Fontana, southern California. Rapid rock‐varnish formation is associated with an unidentified cocci bacterium that grows rapidly in culturing experiments, combined with the likelihood that Mn‐rich solutions flow over slag surfaces. A new model is proposed for the formation of silica glaze, involving soluble Al‐Si complexes and the nature of wetting films. Iron skins occur where runoff is concentrated, and where iron bacteria grow.Observations indicate: (i) substrate can be important in supplying Mn, as well as maintaining a stable surface and channelling runoff to microspots where varnish grows; (ii) ignorance of boundary layer pH/Eh conditions makes chemical‐physical models of varnish formation speculative; (iii) the balance between cementation of recently nucleated varnishes and erosional shear stresses is poorly understood, but is probably an important limiting factor on varnish growth rates; and (iv) there must be at least two steps in biotic varnishing‐accretion of Mn‐Fe in casts, followed by cementation of clays by eitherin situcast residue or Mn‐Fe remobilized from casts. Varnish accretion may be limited by the rate at which both steps occur. Rapid development of readily distinguishable manganiferous rock varnishes at this post‐1952 site highlights the danger of speculation on the ages of landforms based solely on the appearance of
ISSN:0197-9337
DOI:10.1002/esp.3290200606
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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6. |
A partial explanation of the dependency of hydraulic conductivity on positive pore water pressure in peat soils |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 561-566
Andrew J. Baird,
Simon W. Gaffney,
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摘要:
AbstractPart of the relationship between positive pore water pressures and hydraulic conductivity in peat soils may be explained by accumulations of methane bubbles. We show how compression and expansion of gas bubbles with changes in pore water pressure could cause changes in hydraulic conductivity and thus help to explain some observations of dependency of hydraulic conductivity in peats on pore water pressure. Consideration is also given to the effect on hydraulic conductivities of methane gas going into solution with increase in pore water pressure.
ISSN:0197-9337
DOI:10.1002/esp.3290200607
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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7. |
Rates of rock surface lowering, Princess Elizabeth land, Eastern Antarctica |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 567-573
A. P. Spate,
J. S. Burgess,
J. Shevlin,
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摘要:
AbstractA series of micro‐erosion‐meter sites on different rock types and in differing wind regimes was established and re‐read after four years on two sites in the Larsemann and Vestfold Hills. These two oases in Eastern Antarctica are subjected to both wind abrasion and salt wedging. The measurements displayed bimodal distributions, indicating that both abrasion and single‐grain detachment could be observed. Surface lowering rates of 0·015 and 0·022 mm a−1were demonstrated for the Larsemann and Vestfold Hills, r
ISSN:0197-9337
DOI:10.1002/esp.3290200608
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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8. |
I.A.G. newsletter. International association of geomorphologists newsletter no. 12(1/1995) |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 575-578
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ISSN:0197-9337
DOI:10.1002/esp.3290200609
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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9. |
Landnutzung und Landschaftsde‐Gradation im Tiefland von Kitui und in den Taita Hills (Kenia) edited by F. Runge and J. Sponeman, Paderborner Geographische Studien Band 4, Im Selbstverlag des Faches Geographie, FBI, Universitä t‐GH Paderborn, 1992. No of pages: 119. ISBN 3‐9800875‐4‐9 |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 579-580
Frank Ahnert,
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ISSN:0197-9337
DOI:10.1002/esp.3290200611
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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10. |
Le Relief de la France: Coupes et Croquis by Y. Battiau‐Queney, Masson, Paris, 1993. No. of pages: xiv + 252. Price: 160FF. ISBN 2‐225‐84145‐4 |
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Earth Surface Processes and Landforms,
Volume 20,
Issue 6,
1995,
Page 580-581
Jean‐Luc Peiry,
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ISSN:0197-9337
DOI:10.1002/esp.3290200612
出版商:John Wiley&Sons, Ltd
年代:1995
数据来源: WILEY
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