On the origin and glacial transport of erratics of Jotnian sandstone in southwestern Finland
Late Proterozoic Jotnian sandstone erratics were transported during the last Quaternary glaciation from the source area in Satakunta at the coast of southwestern Finland and the bottom of the Bothnian Sea to the southeast as far as Estonia, Latvia and Russia. The frequencies of the sandstone erratic...
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| Format: | Article |
| Language: | English |
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Geological Society of Finland
1996-12-01
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| Series: | Bulletin of the Geological Society of Finland |
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| Online Access: | http://www.geologinenseura.fi/bulletin/Volume68/sgs_bt_068_2_pages_072_083.pdf |
| Summary: | Late Proterozoic Jotnian sandstone erratics were transported during the last Quaternary glaciation from the source area in Satakunta at the coast of southwestern Finland and the bottom of the Bothnian Sea to the southeast as far as Estonia, Latvia and Russia. The frequencies of the sandstone erratics show that they were transported greater distances than indicators of other rocks in the southern parts of Finland. In addition, high frequencies in small areas, south of Salo and in Bromarv, indicate that there are or were small separate source areas of Jotnian sandstone outside the main area. This is supported by the distribution of erratics of Cambrian sandstone and Ordovician sedimentary rocks in the same area. The tracing of possible small occurrences of Jotnian sandstone or Palaeozoic rocks is, however, difficult in an area with numerous faults and fracture zones in the Precambrian bedrock, where the depressions are covered by thick Quaternary drift.
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| ISSN: | 0367-5211 1799-4632 |