Aantekeningen bij zwerfsteentellingen
Grondboor & Hamer , Volume 20 - Issue 5 p. 207- 209
Methodical complications, that arise when studying boulder clays, are discussed. Moraines of different age, composition and provenance are found in the Netherlands. Glacial rafts also occur. Decalcification and disintegration by frostaction may change the character of the association of erratics entirely. The stones already greatly varied in size before they were taken up in the moraine. This was caused by hardrock properties such as joints, concretions, stratification and also by processes such as the abrasion of pebbles. Such phenomena may reduce the diagnostic value of indicatorboulders. The desirability of more precise observations is stressed and some examples of such work are presented. It is regrettable, that Scandinavian geologists are not anymore working on erratics outside their countries.
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