A Geoscience Digital Image Library
A Geoscience Digital Image Library
| Title | Jumble of obsidian and pumice, Obsidian Dome, just north of Mammoth Lakes, California, USA |
|---|---|
| Description | Obsidian Dome is a 600 year old (very young!) rhyolite dome near Mammoth Lakes in eastern California. It formed by rapid cooling of a viscous lava. The inner part contains some relatively solid rhyolite, but the outer parts consist of a jumbled mass of boulders and rocks of various sizes. Many are made of pumice and/or volcanic glass. A plaque near the dome says “This mile-wide, 300 foot high rhyolite dome is one of a chain of similar domes extending from Mono Lake to the Inyo Craters. The domes in the northern two-thirds of the chain are known as the Mono Craters.” The overall composition of the material shown in this picture is the same as a rhyolite (fine grained extrusive igneous rock) and a granite (coarser grained intrusive igneous rock) but cooling was so rapid that even small mineral grains did not have time to form in many of the boulders. |
| Chronostratigraphy | recent |
| Geologic province | Inyo Volcanic Field |
| Location | USA ▹ California ▹ Mono. Near Mammoth Lakes. Inyo National Forest. |
| Photographer | Dexter Perkins. 2001-05-22. |
| Collection | E15102199. |
| Key words | rhyolite, obsidian, pumice, granite, dome |
| Tech details | 413 KB. Vista. Canon Eos Rebel, 55 mm lens, Fuji Sensia 100. |
| GeoDIL number | 536 |
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