摘要:

ABSTRACTThe terrestrial paleoclimatic records and explanations are much more uncertain than generally claimed. Similarly, the understanding of the solar physics and variations are still very limited. The galactic variables with solar-terrestrial impact are hitherto almost unexplored. Nevertheless, we can provide examples of terrestrial geophysical variables that originate, or seem to originate, also from solar and galactic forces.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880096

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThe author leads a research project to test his theory of nival erosion and glacial protection of cirque forms in Scania (Rapp 1982 a and b), with comparative studies in Lappland and in middle and south Europe. The project will test the following postulates.The tundra periods in Scania, e.g. the Older and Younger Dryas had permafrost climate with strong effects of snow drifting by easterly and westerly winter storms. This is likely from observations of fossil ice-wedge casts on sandy plains in Scania, and from wind-polished bedrock and blocks with fluting marks, from easterly and westerly directions (G. Johnsson,Å. Mattson, H. Svensson). Large masses of snow were then trapped in the valleys of Söderåsen, forming nivation hollows and glacial cirques. This was also the case during the much longer tundra periods before the advances of the Quaternary main ice sheets over Scania. Small local glaciers and many nivation hollows were formed and grew, before the major ice advances. The canyons, cirques and nivation hollows were protected from destructive ice-sheet scour as their own, local ice-fill, made the large glacier slide over without much erosion (Rapp 1982). Our research program in Lappland will include winter and summer studies of contemporary nivation processes and resulting land forms at selected sites in the mountains of Abisko.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880097

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTSome single observations of low-lying cirques are published from central and northern Sweden (Agrell 1977, Vilborg 1977). If they are true cirques they give important information about the growing phases of the Quaternary glaciations. More examples are to be expected. In this paper the new topographic maps are used for identification of possible cirques. A lot of specimens are mapped and discussed as to form, size, altitude of the cirque-bearing hill, aspect and regional distribution. A comparison is made with the better preserved cirques of the Swedish Caledonides. It is concluded that the mapped forms may be true glacial cirques but other origins, notably erosion by ice sheets, are not definitely excluded.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880098

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThe present paper on cirque forms in Central Sweden deals with a survey, which in its turn is a continuation of a corresponding one of cirque forms in Swedish Lapland (Vilborg 1977). Compared with the latter survey the now used cirque form classification system has been slightly changed and—hopefully—improved.About 550 cirque forms have been mapped within a surveyd area of ca 110 000 km2, practically all without glaciers. However, only 16% of them are interpreted as fairly credible glacial cirques. The regional, as well as the vertical and aspect distributions of these cirque forms have been briefly examined. On the whole, the various distribution patterns can be explained in the light of general land relief, relative relief of land surface, the orientation of more pronounced mountain crest/ridges, fracture zones of regional persistance and some further variables.Special interest has been payed to mountain areas with many cirque forms in relation to adjacent areas of about the same altitude, almost lacking cirque forms. Rock type seems to be at least one differentiating factor. Some comments are also made on indications of so-called cirque stairways with regard to their appearance and location.About 50 cirque forms are situated outside the mountain region, at comparatively low levels. They indicate a conspicously great depression of the glaciation level(s) during Pleistocene if the interpretation of them as glacial cirques will prove to be correct. A few specimens are described more closely.In the light of the cirque form distribution patterns of Lapland and Central Sweden some reflections are made on the optimum cirque formation periods. Are the initial stages of the Pleistocene glaciations necessarily those periods when the majority of the best developed Swedish glacial cirques had their main backwall retreat and downward cutting-out?

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880099

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTA morphological study which included detailed mapping and ice fabric studies was conducted on the ice-cored lateral moraines in the Tarfala valley, Lapland, Sweden. This study reveals a close association between the lateral moraines and the adjacent talus tongues. The talus tongues are deflected in their lower portions in the direction of glacier flow. Ridges of talus debris continue down-glacier as distinct features which are here termed talus trails. The talus trails coalesce to form the lateral moraines. These relationships suggest the ice-cored moraines are composed primarily of previously englacial debris and glacier ice. The deflected talus tongues and talus trails represent fossil ice flowlines. The geometry of these flowlines reflects conditions characteristic of an accumulation zone and are thus believed to be a unique class of glacial deposits. These deposits are responsible for the bulk and geometry of the lateral moraines and are also the oldest parts of the moraines. The deflected talus tongues and talus trails are estimated to have been formed between 2400 and 2700 BP. These deposits are used to tentatively infer some aspects of the climatic regime during this period. Reconstruction of local accumulation zones and associated equilibrium lines indicates a mean summer temperature decrease of at least 0.9°C. Morphological considerations indicate an unusually large input of talus debris during this period.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880100

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTEmpirical relations are developed between river-meander features and water-discharge characteristics for 19 reaches along Swedish rivers. In these relations, either average channel width or average radius of curvature of meander arcs can be used to estimate average annual peak discharge and average daily discharge. By accepting certain assumptions, the relations can be applied to other meandering Swedish rivers, present or ancient. TheÖster-Dalälven River near Mora is used as an example.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880101

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTThe purpose of this work has been: (1) to collect data on certain lake morphometrical characteristics (area, volume and maximum depth) and geomorphological provenance from as many lakes as possible throughout Sweden, i.e., to establish a geomorphological lake register, and (2) to test a working hypothesis concerning a quantifiable relationship between lake morphometry and lake surroundings. Presently, the register includes 1060 lakes.The working hypothesis has been verified by means of a cluster analysis. The results include a new division of Sweden into five regions with lakes of similar morphometry. These results may, e.g., be used to statistically determine the most probable,‘normal’, values of lake volume, mean and maximum depth, lake form and percentage area of lake bottom dominated by processes of erosion and transportation, from knowledge of lake area alone.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880102

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTSediments and morphology of large-scale bed forms in the offshore zone (depth:–2 to–8 m) situated in the western Baltic, just south of Copenhagen, have been investigated by means of airphoto interpretations and diving observations.The bed forms appear as isolated stripes on the sea bottom, are more than 1 km long, 50–200 m broad, but only 0.2-0.3 m high and run almost normal to the shoreface. It was found that, although asymmetrical, the stripes show no evidences of netmigration for the last 35 years. They consist of homogeneous fine-sand, and rest upon smooth, glacial drift materials partly covered with lag sediments. Geometrically, the large-scale bed forms can be classified as sand ribbons, but from a dynamical point of view, they can hardly be explained as longitudinal current bed forms.On the basis of the local wave and current environment some possible interpretations of the bed form origin are discussed.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880103

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTShorelines along the Enköping esker were levelled and plotted to distance diagrams. The various indications of a shoreline did not directly show a clear stratification and could not be used for a calculation of the assumed increase of land uplift in a south-north direction. Instead, a modern isobase system based mainly on repeated precise levellings was used to refer the weighted shoreline indications to the isobase of Stockholm and Uppsala respectively. An examination of the altitudes of the shoreline indications derived in this way, drawn as histograms, shows interesting maxima, one around 30 m above mean sea-level (a.m.s.1.) and another around 50 m.a.m.s.1. reduced to the isobase of Stockholm. The possible correlation of these maxima and other minor maxima with the Litorina transgressions observed by other authors is discussed.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880104

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor

摘要:

ABSTRACTLongshore transport of shore pebbles and cobbles by waves and ice was studied in the Airisto area in the SW Finnish Archipelago for five years (1976–81) by means of painted clasts 1–10 cm in size. Seven gravelly, stony shores were selected as observation sites. The net transport distances of the marked material from the starting-lines were measured once every year. The results were treated statistically.The maximum net movement of pebbles and cobbles along the shore occurred in the swash zone during severe storms when the water level is often high. It was at a minimum on the backshore and in the surf zone. The effects of the open sea were, in general, reflected in the directions and net distances of the longshore movements at the observation sites. The mean net distance travelled during the five research years was short, only 4.2 m. In the last year it was longest. 1.9 m. which was due to favourable wind conditions and the action of wind-driven ice during breakup. The net distances travelled by some individual pebbles and cobbles along the shore were as much as 10–20 m per year. Pebbles of 2–6 cm and cobbles of 7–9 cm in size travelled on average farthest while pebbles of 1–2 cm and cobbles of 6–7 cm and 9–10 cm in size travelled on average the shortest net distances.

ISSN:0435-3676    

DOI:10.1080/04353676.1984.11880105

出版商:Taylor&Francis    

年代:1984

数据来源: Taylor