Feldspars from the Meldon Aplite, Devonshire, England

M. Nawaz Chaudhry
Department of Geology, University of the Panjab, Lahore, West Pakistan

Summary: Chemical analyses of nine K-feldspars and thirteen albites, along with their optical, physical, and X-ray data are presented. The obliquity values Δ = 12·5(d131-d13¯1) of the K-feldspars are found to be independent of the contents of silica and volatiles in the rocks. The role of temperature as the primary factor affecting the obliquity values is stressed. The relationship between the (An + Ab) content of the potassic phase of K-feldspars and 2Vα is shown diagrammatically.

Mineralogical Magazine; June 1971 v. 38; no. 294; p. 179-185; DOI: 10.1180/minmag.1971.038.294.06
© 1971, The Mineralogical Society
Mineralogical Society (www.minersoc.org)