A Note on Some Dalradian Stilpnomelanes and Their Oxidation

Colin M. Graham1
Department of Geology, University of California, Los Angeles, California 90024
1Present address: Dept. of Geology, The University, Edinburgh EH9 3JW

Summary: The widespread ferristilpnomelane in Dalradian metabasites of the south-west Scottish Highlands has usually formed by secondary oxidation of primary ferrostilpnomelane, probably during weathering. Ferrostilpnomelane oxidizes readily in polished thin sections open to the atmosphere over a period of months, and microprobe examination of the resulting ferristilpnomelane suggests a change in the role of potassium in the structure during oxidation.

Mineralogical Magazine; March 1976 v. 40; no. 313; p. 467-472; DOI: 10.1180/minmag.1976.040.313.05
© 1976, The Mineralogical Society
Mineralogical Society (www.minersoc.org)