A Geoscience Digital Image Library

TitleThin section of latite porphyry
DescriptionThis is a plain polarized thin section of latite porphyry. The abundant euhedral to subhedral lavradorite phenocrysts show characteristic albite twinning and some incipient alteration. Augite phenocrysts are less common and are typiaclly altered to biotite and/or chlorite. Small magnetite and pyrite grains comprise roughly one percent. The groundmass is granular intergrowth of plagioclase (andesine and labradorite), sanidine, augite, biotite and tiny cubes of magnetite.
ChronostratigraphyUpper Cretaceous
Geologic provinceTwo Medicine Formation
LocationUSA ▹ Montana ▹ Lewis and Clark. Near Havre. Wolf Creek.
PhotographerDarla Sondrol. 2002-04-08.
CollectionWard’s Collection of Classic North American Rocks #23.
Key wordslatite, porphyry, Bearpaw Mountains, Montana, thin section
Tech details1.23 MB. Thin section. Nikon FDX-35.
GeoDIL number2625