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Sediment anisotropy coincides with moraine ridge trend in south-central Finnish Lapland 总被引：1，自引：0，他引：1
RAIMO SUTINEN MAARIT MIDDLETON PAULIINA LIWATA MATTI PIEKKARI EIJA HYVÖNEN 《Boreas: An International Journal of Quaternary Research》2009,38(3):638-646
The morpho-sedimentary anisotropy of a field of moraine ridges, classified previously as ribbed moraine, was studied by means of ASTER satellite data, airborne radiometric (AR) data, digital elevation models (DEMs) and azimuthal measurement of electrical conductivity (σa ) in Kivitaipale, south-central Finnish Lapland. The 20 km long corridor of moraine ridges is diagonally oriented to the youngest (Late Weichselian) active-ice streamlined features and presumably dates back to post-Younger Dryas. The maximum σa anisotropy of sediments is parallel to the orientation of the ridge crests. Crudely to well stratified gravels and sands of glaciofluvial open channel origin and moderately sorted sediments attributed to glaciofluvial sliding bed facies are exposed in the cores of the ridges, whereas signs of (basal) till cover or glaciodynamic deformations are absent. On the basis of morpho-sedimentary anisotropy, we contend that the origin of the studied corridor of ridges is linked to subglacial outburst event(s) rather than a transverse-to-ice-flow origin of ribbed moraine. The triggering mechanism for the outburst(s) remains unresolved, yet the timing of outburst(s), concurrent with the maximum post-Younger Dryas fault instability, may imply that earthquake(s) contributed to subglacial drainage. 相似文献
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HEJKKI HIRVAS KAUKO KORPELA RAIMO KUJANSUU 《Boreas: An International Journal of Quaternary Research》1981,10(4):423-431
A historical review is given of the stratigraphic and chronological research of the Weichselian glaciation in Finland. Submorainic interglacial organogenic deposits have been found in Finnish Lapland and Ostrobothnia. Radiocarbon analyses give ages of over 50,000 years B.P. and the microfissil assemblages indicate climatic conditions that are more fovourable than at present. Interstadial deposits with radiocarbon ages of 42,000 to over 50,000 years B.P. contain fossil assemblages in dicating a poorer climate than at present. A tentative correlation of the Weichselian stratigraphy by various authors is presented. 相似文献
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HEIKKI IGNATIUS KAUKO KORPELA RAIMO KUJANSUU 《Boreas: An International Journal of Quaternary Research》1980,9(4):217-228
Various concepts of the deglaciation of Finland are presented in the form of a historical review. The suggestions of an early (12,000–10,000 B.P) deglaciation of eastern and northern Finland are considered to be erroneous. A map depicting the ice recession as successive ice-marginal lines is presented. According to radiocarbon dates the Finnish territory was entirely deglaciated slightly after 9000 B. P. 相似文献
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