DEGLACIATION IN EASTERN AND CENTRAL ... - arkisto.gsf.fi

13
HOW THE GLACIAL GI.,ACIAL THEORY THEORYWAS WAS ACCEPTED ACCEPTED IN FINLAND FINI.AND
(according to Rainio 1994, pp. 20-23)
Observations calling for explanation
explanation
In 1740, the Swedish prospector Daniel Daniel Tilas (1712-1772) showed that the source of
erratic boulders resting on a 'wrong' rock in Finland Finland should be searched for in the
north or northwest (Nathorst, 1894, p. 50). In 1821 and 1822, the tLLe Englishman
Strangways Strangways listed localities localities in Finland where the bedrock was a source of boulders
that had migrated to Russia Russia (Strangways, 1821, L82L, pp. 39-30; 1822, p. 10).
Networks of eskers eskers and sandy ice marginal marginal deposits were described from Finland in
the 18th century (Heinricius, 1895; 1895; Argillander, Argillander, 1784). 1784). The landforms landforms were
considered as entities and the the first frrst explanations of of their genesis were made in the
early 19th century. In 1819, for 1o" example, elample, Henrik Henrik Deutsch Deutsch concluded that some
eskers were were'products 'products of water' watef (Deutsch, 1819, p. 369) (Rainio & Kukkonen, 1985, 198b,
p. 11).
Striae were known back at the the time time of Tilas; rilas; what what was not not known known was that they
showed parallel orientation within large areas (Sefström, 1837, 1837, p. p. 1). Encouraged by
the example of the Swedish chemist chemist N.G. N.G. Sefström (1787-1845), Finnish Finnish scholars
began began to collect collect information on striae striae in in the the late late 1830s.
Potholes Potholes were studied at around the the same seme time (Nordenskiöld, 1842), and the
contribution of flowing water to their their genesis genesis was was acknowledged. In the late 1830s,
Hofmann Hofmann and Boehtlingk Boehtlingk made observations on the transport of ofboulders boulders in Finland,
and on uplift and ancient shores (Hofmann, 1841, 1841, pp. 119-120 and 124-125; 124-L25;
Boehtlingk, 1839, 1839, 1840a). 1840a).
The frrst first universally applicable explanation proposed was was a adeluge. deluge. Next came
rapid, large-scale large-scale movements of the the Earth's Earth's crust, floods floods and parallel movements of
great earth masses masses (Boehtlingk, 1939, p. 4).
Among the the foreign scholars who studied Finland was Strangways (1821, (1821, p. 42). He
deduced the direction ofthe of the flooding waters from the transport directions of erratics
or from the trend of striae striae and eskers. Another was Sefström, a Swede whose rolling
stone, or petridelaunian, flood theory theory had enormous influence in Finland (Sefström, (Sefström,
1837). 1837). According to him, a colossal stream stream had had loosened and transported rolling
stones and sand, erratics erratics and gravel gravel from north north to south. Stones and sand had
polished the the roche moutonn6es. moutonnees. As the the force ofthe of the stream abated, gravel gravel and sand
deposited as long eskers parallel to its flow. (Sefström, 1837; Rainio, 1994, Fig. 4)