Feldspar grains of sandstones of southeastern Minnesota are characterized by secondary enlargements. Detailed study of the feldspar of the New Richmond sandstone shows rounded detrital grains of microcline have been enlarged by growth of orthoclase. The feldspar enlargements may possibly represent a sedimentary product, but an alternate hypothesis of hydrothermal origin is also considered.

First Page Preview

First page PDF preview
You do not currently have access to this article.