Argonbestimmungen an Kaliummineralien—IV die frage der argonverluste in kalifeldspäten und glimmermineralien
1957; Elsevier BV; Volume: 12; Issue: 4 Linguagem: Inglês
10.1016/0016-7037(57)90043-1
ISSN1872-9533
Autores Tópico(s)Geology and Paleoclimatology Research
ResumoZusammenfassung The age of different samples of felspar and mica were determined by the potassium-argon method. It was shown that the argon content of felspar is about 5 per cent legs than the content of mica in the pegmatite from Hechtsberg, Black Forest, Germany (age c. 250 million years). Approximately the same result was found with the pegmatite from Hobol, South Norway (age c. 960 million years). Careful analyses of those samples with a polarizing microscope showed the existence of metamorphic transformations in the felspar. This seems to be the reason for the loss of argon in felspar. In addition, some measurements were made of the argon losses in different grain sizes of felspar. Losses of argon were first observed when the felspar was pulverized to a grain size of less than 100 microns. On further pulverizing the felspar to a grain size of 5 to 10 microns, argon losses of 30 to 50 per cent were found.
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