ISSN:0197-9337    

DOI:10.1002/esp.3290090402

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

ISSN:0197-9337    

DOI:10.1002/esp.3290090403

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractAccumulations of stored sediments in a sub‐alpine environment of a front range of New Zealand's Southern Alps closely resemble sieve deposits previously described from southeastern California.The locations of such deposits, within active river channels, has important implications for long term sediment yields from catchments where such deposits occur. The catastrophic failure of a sieve deposit in the Torlesse Stream catchment, the site of an earlier investigation of mountain stream sediments, resulted in a sediment yield equivalent to a third of the total yield recorded over an eight‐year period. Derived bed‐load transport rates represent, at a minimum, a four‐fold increase over calculated average transport rates.Such deposits are only likely to fail during extreme low frequency events since their highly permeable gravels allow for the continuation of stream flow underneath the bulk of the deposit and restricts significant increases in moisture content within the deposit. The loss of water is responsible for the inhibition of flowage‐type mass movement transport mechanisms wherein available water contributes to the maintenance of positive pore pressures.For the example studied here the percentage of silt and clay is less than 3 per cent of the total sample while sorting values (σ1) are generally less than 2.0ϕ. These values are approximately one‐third and one‐half respectively, of typical values obtained for these parameters from debris flow deposits. The feature described here is believed to have originated through failure of a higher altitude perched scree‐field. This mode of origin would account for the distinctive sedimen

ISSN:0197-9337    

DOI:10.1002/esp.3290090404

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractMeasurements were made of the water content in coastal rocks, by simulating tidal oscillations in the laboratory, and by field measurement in eastern Canada. If rapid freezing takes place upon exposure to the air, saturation levels may be high enough to permit frost weathering in fine grained rocks in the lower portions of the intertidal zone. Near the high tidal level, however, it may be dependent upon a supply of water from the ice foot and from melting snow. If freezing is slow, frost action may be inhibited by desorption of the rocks while they are exposed by the ebb tide. There was no evidence of a level of permanent sea water saturation within the intertidal zone. Ambient temperature and humidity may affect the rate of rock desorption.

ISSN:0197-9337    

DOI:10.1002/esp.3290090405

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractStudy of two subareas of the same large basin in North Greece determined that differences in processes and form exist between the two subareas. These differences were brought on by man's interference upon one of the subareas.In area A, seminatural vegetation promotes throughflow and protects the surface from overland flow. Hence, natural erosion takes place primarily by channel deepening and infall of side slopes into the channels.In area B, clearing of the seminatural vegetation and the improper ploughing for cultivation increases the overland flow which promotes slope erosion but the augmented debris supply has checked channel erosion. These processes change the form of the drainage basins of the area.

ISSN:0197-9337    

DOI:10.1002/esp.3290090406

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThree groups of micromorphological features are recognized in the river terrace deposits of the Kennet Valley. These are orthic pedological features, orthic pedological features disrupted by cryoturbation, and transport‐inherited features. Fluvial and solifluction processes account for the presence of the transport‐inherited features. Used in conjunction with sedimentological and geomorphological investigations the distribution, composition, size, shape, and relative proportions of micromorphological features are helpful in separating pedogenically‐altered materials from undisturbed sediments, and in recognizing the occurrence of more than one phase of soil develo

ISSN:0197-9337    

DOI:10.1002/esp.3290090407

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractMineralogical study of samples from depression fills on an isolated basalt plateau in Central Sardinia showed that, although the basalt is free of quartz and mica, fair amounts of these minerals occur in the finer fractions. Results from X‐ray analyses of silt fractions and morphoscopical analyses of sand fractions indicate that the bulk of the quartz and mica is of eolian origin.The eolian quartz is predominantly of medium and coarse silt size and, in the upper 10 cm of the depression fills, constitutes about 20 per cent of the soil mass (approx. 20 kg/m2). Eolian mica is present in smaller amounts and is of medium silt or smaller size.The provenance of the eolian material could not be established with certainty, although a local origin can be exclude

ISSN:0197-9337    

DOI:10.1002/esp.3290090408

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractPrevious research has shown that either hydraulic action or creep may be the dominant process transporting coarse debris down hillslopes in the American Southwest. This study analyses the movement over 16 years of painted stones on two hillslopes in the central Mojave Desert to ascertain which of these two processes dominate in this region. The distance moved (M) is found to be directly related to length of overland flow (X) and hillslope gradient (S), and inversely related to particle size (D). The fact thatMis more highly correlated withXthan withSsuggests that hydraulic action rather than creep is the dominant process. It is concluded that this is probably the case over most of the Mojave and Sonoran Deserts on slopes up to at least 24°, and that it is only at higher elevations where winters are more severe that creep may become dominant

ISSN:0197-9337    

DOI:10.1002/esp.3290090409

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractThis paper presents a case study of runoff and sediment generation under Submediterranean rangeland conditions (Ardèche drainage basin, France). Measurements indicate that on a rough hillslope interrill runoff and sediment are not produced uniformly over the slope surface. It is observed that runoff concentrates immediately in non‐permanent interrill flow paths, which under average storm conditions vary in length from 1.0 to 12.5 m. Long interrill flow paths may eventually become permanent. These permanent flow paths, called pre‐rills, are introduced as a new source area, and are considered to be the initial stage in the development of rills. Along pre‐rills considerable quantities of runoff and sediment are carried away.This study also shows that calculations based on interrill, pre‐rill, and rill runoff will only have significance if storm and soil conditions are specified in detail. It is concluded from a correlation analysis between the runoff volume and the amount of soil loss on a storm‐by‐storm basis that the runoff volume alone cannot explain the amount of sediment that is generated in each source area; soil availability is an additional factor that must be taken

ISSN:0197-9337    

DOI:10.1002/esp.3290090410

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY

摘要:

AbstractTumbler simulations of abrasion processes affecting rocks on basaltic marine benches have clarified the effects of mass and volume of rock fragments on their rate of wear. Several experiments indicate that rate of basalt wear increases with mass in the interval 1 g to 8 g, but is not related to volume of fragments abraded in seawater.Relatively small quantities of rock flour suspended in the immersant seawater substantially reduced the rate of basalt wear. Basalt and calcareous beachrock responded differently in systems with both rock types tumbling together.Examination of the cuttings from these low‐energy encounters suggests that abrasion on elevated benches along exposed seacoasts reduces virtually all clastic material to particles of silt size or smaller, producing essentially no san

ISSN:0197-9337    

DOI:10.1002/esp.3290090411

出版商:John Wiley&Sons, Ltd    

年代:1984

数据来源: WILEY