Low-Temperature Thermal Effects in Natural Volcanic Glasses Due to Strain

A. Ewart and M. Fieldes
New Zealand Geological Survey
Soil Bureau, Department of Scientific and Industrial Research, New Zealand.

Summary: Sharp exothermic peaks occurring at about 90° C during D.T.A. treatment of natural volcanic glasses are described and are shown to be due to release of external strain. This is probably triggered by loss of surface water. No systematic variation in strain could be found in glass of different geological histories, but strain is found to decrease during natural weathering of volcanic glasses. Differences in weatherability of natural glasses may be related to degree of surface strain.

Mineralogical Magazine; September 1962 v. 33; no. 258; p. 237-246; DOI: 10.1180/minmag.1962.033.258.06
© 1962, The Mineralogical Society
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