Czwartorzędowe ruchy pionowe wybrzeży Hornsundu i geneza przystokowych wałów kamienistych
Abstract
REMARKS ON QUATERNARY VERTICAL CRUSTAL MOVEMENTS OF THE HORNSUND COAST AND ORIGIN OF NEARSLOPE STONY RIDGES
Summary
Geological studies in area between the Hansa and Werenskiolda glaciers, carried out by the Author in 1978, made it possible to draw the following conclusions on vertical crusta! movements and origin of nearslope stony ridges.
The Hornsund area has been gradually rising from Late Wurm times. In the Holocene, there presumably took place repeated oscillatory movements which is indicated by sediments differing in 14C age occurring close to one another and at similar level. One of these oscillations is evidenced by relics of sedimentary cover of the Atlantic age, found directly above the Precambrian in the trenches 1-5 at the Nottinghambukta coast.
The results of studies on nearslope stony ridges suggest their origin different from the hitherto accepted. The rocky material is heavily fractured and with numerous slickensides. Moreover, some sorting is traceable. The appearance of individual parts of the ridges does not support their gradual formation but rather rapid one. Such origin of the ridges is also indicated by their sudden ending, not related to any change in inclination of slope along which they are developed. The heavy fracturing of the rocks may be best explained in terms of short-lasting but strong tectonic quakes, whereas mechanical weathering seems to be a derivative phenomenon only. The Author suggests that the youngest rock falls have taken place in this century.
Summary
Geological studies in area between the Hansa and Werenskiolda glaciers, carried out by the Author in 1978, made it possible to draw the following conclusions on vertical crusta! movements and origin of nearslope stony ridges.
The Hornsund area has been gradually rising from Late Wurm times. In the Holocene, there presumably took place repeated oscillatory movements which is indicated by sediments differing in 14C age occurring close to one another and at similar level. One of these oscillations is evidenced by relics of sedimentary cover of the Atlantic age, found directly above the Precambrian in the trenches 1-5 at the Nottinghambukta coast.
The results of studies on nearslope stony ridges suggest their origin different from the hitherto accepted. The rocky material is heavily fractured and with numerous slickensides. Moreover, some sorting is traceable. The appearance of individual parts of the ridges does not support their gradual formation but rather rapid one. Such origin of the ridges is also indicated by their sudden ending, not related to any change in inclination of slope along which they are developed. The heavy fracturing of the rocks may be best explained in terms of short-lasting but strong tectonic quakes, whereas mechanical weathering seems to be a derivative phenomenon only. The Author suggests that the youngest rock falls have taken place in this century.