Plumbogummite-Group Minerals from Mull and Morvern

D. C. Bain
The Macaulay Institute for Soil Research, Craigiebuckler, Aberdeen

Summary: Sandstones from Mull and Morvern, most of which are from the Greensand formation, have been shown by X-ray diffraction to contain minerals of the plumbogummite group in very small amounts in the < 1·4 µm fraction. The minerals were concentrated by HF digestion of the clay minerals. X-ray spectrographic traces show concentrations of Sr, La, Ce, Yt, and Ba, and a semiquantitative spectrochemical analysis also shows a concentration of Ca and Pb and the presence of numerous rare-earth elements. Individual minerals, which have a complex composition and can not be assigned to any one named species, are disseminated throughout the rocks as particles with an estimated size of between 0·1 and 0·25 µm.

Mineralogical Magazine; December 1970 v. 37; no. 292; p. 934-938; DOI: 10.1180/minmag.1970.037.292.10
© 1970, The Mineralogical Society
Mineralogical Society (