摘要:

ABSTRACTThe morphology, morphometry and active processes are described for two km long sections of one west facing and one east facing talus slope in central Spitsbergen. The rock delivery activity to the talus slopes was studied during three summers and compared with the meteorological conditions. The two slopes showed great differences in response to variations in direct sunshine, precipitation events and rapid temperature changes which may explain the observed differencies in morphology and morphometry. Thus, well developed debris flows were almost exclusively found on the east facing slope. A regional inventory of 570 1-km sections of debris slopes in central Spitsbergen showed that debris flows are more abundant in east and north facing slopes or on slopes in very narrow valleys, which supports this observation.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880115

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThis study is an inventory of different types of talus slopes found in the Polish Tatra mountains close to Zakopane. Several active and inactive types were found; rockfall talus, alluvial talus and complex slopes formed by different processes. The slope deposits are described in relation to the altitudinal zonation of climates and the active processes. The paper finally presents an hypothesis, based on our findings, for the Postglacial slope deposition in this part of the Tatra Mts.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880116

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTIn this article observations are made about the sedimentological and geomorphological character of a number ofgrèze-litéedeposits in the Ardèche region in the south of France. There follows an interpretation of the way in which we think the sediments were deposited.The evidence points to an alternation of gelifluction, resulting in the deposition of layers with a well-developed matrix of material<0.05 mm and sliding of coarse gelifracts over a snow cover or over some other low-resistance surface, leading to the formation of openwork layers. It has become clear to us that, contrary to the widely held view, slope wash or nivation can not have contributed much to the deposition of thegrèzes litées, at least in the area of our research.Because it has been impossible to match these results fully with any of the existing hypotheses aboutgrèze-litéeformation, the article ends with a discussion in which our results are compared and contrasted with those of other authors.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880117

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThis paper which summarises part of the 1976 M.Sc. thesis of the author (Astaras 1976), describes the results of a survey carried out in the Mula area of Murcia Province, southeast Spain. It was a preliminary integrated survey for mapping and describing the main natural resources of the Mula area. The work was based upon the integrated survey concept in which the whole complex of the land was examined rather than its individual elements.The method used was“the site analysis approach of Wright”(1972a, 1973). This was a method with similar objectives to the C.S.I.R.O. surveys (1963, 65, 68) but employed different procedures. Instead of subdividing a large area (land system) to particular smaller areas (land units), Wright advocated a synthetic method whereby details are defined for site units before these are grouped together to form the equivalent land complexes. Geomorphological criteria were used in site delimitation since landform characteristics are more readily perceived and measured than other terrain features (soil, vegetation characteristics) both on the ground and from airphotos.The study area was differentiated into“land complexes”which were the basic mapping units. Data were collected within geomorphological“sites”- near planar or regurarly curved slope units - which were combined into“site types”, each comprising a number of individual sites with closely similar gradient and curvature and with distinctive soil and vegetation characteristics. Spatial assemblages of sites characterised by specific site types were then delimited as“land complexes”.The survey area has been differentiated and mapped into seventeen land complexes. Each land complex is described in tabular form and is illustrated by block diagram to show the character and spatial relationships of the constituent site types. Then, the land complexes were themselves grouped into five broader terrain classes according to major landform type, relief amplitude and characteristic gradients.From the use of fieldwork data, the block diagrams and detailed tabular form descriptions of each land complex, and airphoto interpretation, terrain, soil, geology and surface materials, and vegetation - land use maps have been produced.Finally conclusions are drawn about the land complexes and the interelationships between, relief and surface materials, soil and vegetation and land use between and within land complexes.The value of a geomorphological site analysis approach by an interdisciplinary team of specialists (integrated survey) has been pointed out as well.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880118

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTStream channel enlargement occurs in response to change in streamflow regime accompanying the conversion of the natural rainforest cover to different land uses in small headwater basins in Southwestern Nigeria. Stream basins draining areas subjected to traditional agricultural activities tend to develop relatively larger stream channel bankfull cross-sectional areas than those draining areas under fallows of various lengths or forest cover. Stream hydraulic geometry is also significantly altered by agricultural activities. The individual relationship of stream channel width, depth, and velocity to changing discharges, as expressed in the hydraulic exponent values, is shown to change as basin surface passes from one traditional agricultural land use phase to another.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880119

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTA lichenometric growth curve has been derived for the area immediately to the south of the Svartisen ice caps in northern Norway. The curve indicates that lichen growth is considerably faster than postulated in earlier studies in the area. The curve has been applied to a well-developed sequence of moraine ridges at Blokkfjellbreen, an outlet glacier of Vestisen, Svartisen. Lichenometry correctly predicts the approximate margin of the glacier in 1910 A.D., but fails to predict the 1945 A.D. marginal position. There is evidence that several other predicted dates for the ridges are incorrect, and the value of the technique at this site is questioned. Differences between the results obtained in this study and those in earlier studies are explained in terms of differences in the sampling framework, litho- logical variations in the lichen growth rate, altitudinal differences and the potential errors involved with using14C dated surfaces and mine spoil heaps as fixed points for the development of a lichenometric growth curve.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880120

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTLittle is known of the post-glacial sequence of erosion and deposition in upland Britain. In the Carlingill valley, Howgill Fells, Cumbria, Late Pleistocene solifluction surfaces and a high fluvial terrace are dissected by the modern valley within which are Holocene low terraces, tributary alluvial cones and the modern valley floor. This paper establishes a lichen-based sequence for the development of the valley floor and a soil chronosequence on the post-glacial fluvial surfaces.Rhizocarpon geographicum-based lichenometry provides a framework for dating fluvial surfaces over the last 140 years and a multi-species lichen successional sequence can be identified over the same period. A chronosequence of podzol soil development can be identified on the basis of profile morphology, pH and organic content with clear age related differences between valley floor, low and high terraces, with the older high terrace and solifluction surfaces showing mature deep polzols. For the youngest soils sequential iron extraction has allowed the earliest stages of soil formation to be identified.The sequences accord with a regional pattern of early Holocene stabilisation and later disturbance. The modern valley floor shows contrasts between recently stabilised reaches where the channel has locked into bedrock and unstable reaches where the rate of channel migration accords with that of other unstable channels in upland Britain.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880121

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTChanges which have taken place during the last hundred years at the north-eastern glaciers of Svartisen are well-documented. Although the period has been characterised predominantly by glacier retreat, the rates of retreat have varied, as have changes of ice thickness at different altitudes. Comparisons of photogrammetric maps from 1945, 1968, 1975 and 1981 illustrate the differences, both temporal and spatial, at the two largest glaciers. Since 1945, a gradual increase of surface slope of the lower part of Fingerbreen has accompanied a fairly uniform decrease of thickness (about 3 m a-1). Above 500 m, however, the surface slope has changed little and the rate of decrease of ice thickness has not exceeded 2 m a-1. Minor advances of Fingerbreen have interrupted its recession and formed low transverse till ridges. At Lappebreen, retreat almost ceased between 1975 and 1981; above 600 m, the glacier thickness increased. Future studies of glacier change will be a valuable contribution to water resource investigations.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880122

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThis paper analyzes static allometric relationships between the area supplying ice to a fjord glacier, and the fjord trough properties of length, width and depth. The analysis is guided by an underlying assumption that the fjords are eroded into a pre-glacial, fluvial landscape composed primarily of plutonic rocks. The relation between fjord length and ice contributing area appears to be isometric (i.e. the two variables change in constant proportion throughout the study area). Differing degrees of negative allometry exist between ice contributing area, and width, average depth and maximum depth. Abrasion rate models of Boulton and Hallet were applied to a V-shaped valley to gain insight into its transformation into a U-shaped trough; the results of the two models were compared.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880123

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880124

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor