摘要:

ABSTRACTAge determinations on marine mollusks indicate that the northwestern part of Jones Sound became open to the sea more than 9000 conventional radiocarbon years ago. The presence of postglacial marine features at elevations of up to 130 m near Cape Storm, Ellesmere Island, shows that a significant thickness of glacier ice was present in this area, and the differential uplift of pumice and other materials associated with raised beaches provides convincing evidence that the former ice cover was thicker to the west and to the north.Numerous cross-checks have shown that in such an Arctic environment the organic (collagen) fraction of whale bones gives reliable results, as opposed to the bone apatite fraction, which commonly yields ages that are too young. Marine mollusks also are reliable for14C age determinations, and the evidence available from areas of carbonate rocks in the Queen Elizabeth Islands suggests that the ages of marine mollusks are no more than 350 years older than the ages of contemporaneous terrestrial plants.Near Cape Storm over fifty14C age determinations on driftwood, whale bone, and marine mollusks have permitted the construction of a curve showing the pattern of emergence over the past 9000 to 9500 years. Emergence between 9000 and 8000 years ago proceeded at a rate of 7 m/century, and over one-half of the total emergence (70 m out of 130 m) since the initial incursion of the sea took place during this interval. By 6500 to 4500 years ago emergence had slowed to 0.8 m/century, and for the last 2400 years it has averaged500 years. The concentration of the pumice and the nature of the features associated with it suggest that its deposition may be related to: 1) a eustatic rise close to 5000 years ago; 2) a period of more open water, when wave action and storm surges would have been more effective; 3) a combination of these two factors. The formation of the strandline where the pumice occurs is not believed to be related to a slowing-down or cessation of uplift due to the thickening of ice caps and glaciers.

ISSN:0435-3676    

DOI:10.1080/04353676.1975.11879905

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

AbstractThe theory of linear reservoirs is applied to discharge data from Storglaciären and Isfallsglaciären, near Kebnekaise in northern Sweden, during 1 to 17 August 1969. This period is almost without precipitation.Time series analysis is used to describe storage parameters for both of the glaciers. These parameters describe the characteristics of the internal drainage from each glacier. The analysis shows that Storglaciären has two and Isfallsglaciären has three storages in their internal drainage systems. The impulse delay to maximum discharge is within three and four hours.The input of the model is based on the energy balance at a melting snow and ice surface. The meteorological parameters used are recorded at Tarfala Research Station. The model seems to describe the internal drainage satisfactorily.During the time series analysis we found that an outburst of water from Isfallsglaciären had taken place. Different attempts are made to calculate the released volume of water.

ISSN:0435-3676    

DOI:10.1080/04353676.1975.11879906

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

AbstractThe variability of soil movement was studied using Young pit and T-bar techniques. Typical sample sizes required to estimate the true mean within±0.50,±0.05 and±0.025 mm are presented. Sample sizes of less than 10 are usually sufficient to estimate mean annual movement in the surface 12.7 cm to±0.50 mm. To increase the precision of estimate to±0.05 mm a sample size of more than 100 observations may be required. T-bar movements were much more variable on south than on north facing slopes. The type of pin used in Young pit studies was shown to influence the amount of movement.

ISSN:0435-3676    

DOI:10.1080/04353676.1975.11879907

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

AbstractMeasurement and observation of rill flow and sediment transport shows that the highest discharges and sediment load are related to flow from rills developed from melting snow cover. Snow patches act as sediment traps and yield later summer flow and minor fine-textured loads. The redistribution of fine-grained sediments derived under weathering in the high-arctic regime results in thick accumulations of niveo-alluvial sediments on valley floors which are intensively homogenized by physical and biological agencies.

ISSN:0435-3676    

DOI:10.1080/04353676.1975.11879908

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor

摘要:

AbstractAspects of engineering—oriented and geo-morphological runup studies are discussed in relation to the fact that there is little field data against which to check theoretical and model-derived conclusions concerning swashzone flow. Also, it is suggested that there has been little consideration of the effects of variability in wave trains on beach face changes. The“phase-difference”model of Kemp (1958) is examined and shown to be useful in this regard.The results of 21 experiments in which swash (2133) and backwash (1631) velocities were measured together with other surf and runup properties are presented and discussed. The data are forHb0.3 to 2.44 m;Tb7.5–10.0 sees, and characterise non-barred, high energy, mesotidal, mixed sand and gravel beaches of mild slope (5–12°) at Kaikoura, New Zealand.Breaker height is shown to be the primary control of swash length as predicted by Kemp while phase of flow exerts important effects on the temporal structure and hence the net circulation of sediments entrained by the flow. Velocities were determined with a force-plate dynamometer having an accuracy of±15 cm sec-1. Average maximum runup velocity was 168.0 cm sec-land the average duration was 2.98 sees. Backwash velocities averaged 140 cm sec-1with a mean duration of 4.25 sees. Runup velocities conformed to a near-Gaussian probability distribution and 20–60 % of the incident wave velocity is transmitted to runup velocity. The relationship between relative runup velocity and breaker energy is negative—exponential in form for flow between the breakers and still water level. This result is the opposite of one obtained on steep, slopes in a model tank by earlier workers.

ISSN:0435-3676    

DOI:10.1080/04353676.1975.11879909

出版商:Taylor&Francis    

年代:1975

数据来源: Taylor