A Geoscience Digital Image Library
A Geoscience Digital Image Library
| Title | Thin section of tonalite (quartz diorite) |
|---|---|
| Description | This is a plain polarized thin section of tonalite (quartz diorite). The sodic plagioclase and hornblende are subhedral. The other essential species, quartz and biotite, are anhedral. Some of the basal sections of hornblende show twinning. Biotite is partly chlortizied. Coarse anhedral epidote and orthoclase, magnetite, apatite, and allanite are accessories. Plagioclase is slightly zoned; quartz is undulatory in extinction. |
| Chronostratigraphy | Upper Cretaceous |
| Geologic province | Bonsall Tonalite |
| Location | USA ▹ California ▹ San Diego. Near San Diego. |
| Photographer | Darla Sondrol. 2002-04-09. |
| Collection | Ward’s Collection of Classic North American Rocks #24. |
| Key words | Bonsall, tonalite, quartz diorite, California, thin section |
| Tech details | 672 KB. Thin section. Nikon FDX-35. |
| GeoDIL number | 2627 |
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