Title | Thin section of latite porphyry |
Description | This is a cross 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. |
Chronostratigraphy | Upper Cretaceous |
Geologic province | Two Medicine Formation |
Location | USA ▹ Montana ▹ Lewis and Clark. Near Havre. Wolf Creek. |
Photographer | Darla Sondrol. 2002-04-08. |
Collection | Ward’s Collection of Classic North American Rocks #23. |
Key words | latite, porphyry, Bearpaw Mountains, Montana, thin section |
Tech details | 1.17 MB. Thin section. Nikon FDX-35. |
GeoDIL number | 2626 |
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