145 Microscopic Petrography – Cinder Cones and Associated Flows – Diller Cone

The Geology of Crater Lake National Park, Oregon With a reconnaissance of the Cascade Range southward to Mount Shasta by Howell Williams

Microscopic Petrography

 

Cinder Cones and Associated Flows

     Diller Cone

The scoria, agglutinate, and red-crusted lavas near the summit of this cone are typified by plentiful phenocrysts of olivine (5 per cent) and labradorite (25 per cent). In the sections examined, glass is either absent altogether or present only in small amount, the groundmass having a dense intergranular texture made up of slender laths of andesine separated by irregular grains of augite and ore.

 

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