GTK

The Wolf Cave cavern in Karijoki, Kristinestad, is located in an area rich in finds of geological deposits that predate the last Ice Age. The moraine ridge that lies east of the Susivuori, for instance, was formed during the melting phase of the penultimate glaciation some 140 000 years ago. The Susivuori itself is formed of granodiorite, which is some 1,9 billion years old. Granodiorite typically cracks parallel to the surface, a phenomenon which apparently explains the formation of the Wolf Cave cavern. Over the millennia, mechanical and chemical erosion have gradually widened the crack into a cavern. The exact size and shape of the cavern are not yet precisely known because it was filled up to the roof by sediments. So far, only some 80 m² have been excavated. The maximum height of the entrance is 1,5 m. An area of some 25 m² located near and to the east of the entrance is 1.8-2.2 m in height. Ten metres inwards from the entrance the floor forms a small shelf; the height of the ceiling at this point is 0.7 m. 
In order to define the size of the Wolf Cave cavern, a ground radar scan was performed in the winter of 1998 from the top of the Susivuori above the cavern. The method is based on differences in the moisture content of the rock and the soil. According to the scan, the cavern is some 30 metres deep and 25 metres wide at the entrance. The cavern appears to be shaped like a long triangle, and narrows down evenly from the entrance to a width of around two metres at the back. It is difficult to define the height of a cavern with ground radar because the upper layers of sediment are usually dry and only the lower layers are saturated with water. Nevertheless, it appears that the excavated space and the rock shelf behind it are followed directly by a higher space several metres long.
Due to the effects of various geological events, the cavern has filled up with diverse sediments during the Quaternary Period, i.e., the last 2.6 millionyears. So far, six different sediment layers have been identified in the cavern. The topmost layer was formed during the postglacial Ancylus Lake Period some 8000 years ago. The next two layers were formed by older beach phases. The fourth layer is an ancient ground surface, actually an old cavern floor, dated by thermoluminescence to over 100 000 years ago. The two deepest sand and gravel layers (V and VI) are older yet. The most important layers from both an archaeological and a geological point of view are layers IV and V . According to clay mineral studies and pollen analyses, layer IV represents an old ground surface that dates from one of the warmer interglacial periods. Layer IV contains clear Indications of human presence, including fire-cracked rocks. Magnetic susceptibility readings taken at the site indicate the presence of hearths in the cavern.

Wolf Cave N-S profile, stratigrafical model


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