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Summary Report
出版YJT, 1992
URLhttp://books.google.com.hk/books?id=bURPHAAACAAJ&hl=&source=gbs_api
註釋Teollisuudent Voima Oy (TVO) is preparing for the final disposal of spent nuclear fuel from the Olkiluoto nuclear power plant deep in the Finnish bedrock. Kivetty in Konginkangas was one of the five areas selected in 1987 for preliminary site investigations for this purpose. The Kivetty area in Central Finland is located in a Svecokarelian granitoid environment consisting of a complex of synorogenic granitoids 1900-1860 million years in age. The bedrock consists almost entirely of plutonic rocks, i.e. gabbro, porphyritic granodiorite and granite, listed in order of age. The majority of the rock types are porphyritic in character, and supracrustal rocks such as quartz-feldspar schist and gneiss are found occasionally in small xenoliths. The gneisses with their various foliation and other structures occurring as xenoliths represent the oldest deformation in the area. The plutonic rocks bear signs of two deformation phases, which are manifested in the granitoids as a distinct orientation of the mineral grains and flattening of the phenocrysts. Younger tectonic structures include mylonitic seams and minor faults occurring in places. The area and its surroundings are dominated by regional NW-SE fracture zones which divide the bedrock into two large blocks. The Kivetty area is located in such a block, which is further subdivided by local fracture zones. Fractures with steep dips are most frequent. The majority of the fractures occur in two main directions, NE-SW and NW-SE, the latter of which coincides with a regional fracture direction. Horizontal fracturing is significant, particularly in the surface part of the rock down to approx. 100m. Total fracture density normally varies between 1 and 3 pcs/m, although fractures occur very much more frequently in the surface parts than deeper in the rock. The fractures are mainly tight, open fractures being concentrated in the surface parts of the bedrock. The bedrock at Kivetty mainly represents an intact rock body which is massive in structure. The rock types are mainly unweathered, have a small number of fractures and correspond to typical hard, crystalline types in their strength properties.