Black porphyritic glassy dacite from the 1915 eruption of Mt. Lassen (Devastated Area, Lassen Volcano National Park, Cascade Range, northeastern California, USA) : 無料・フリー素材/写真
Black porphyritic glassy dacite from the 1915 eruption of Mt. Lassen (Devastated Area, Lassen Volcano National Park, Cascade Range, northeastern California, USA) / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
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| 説明 | Black porphyritic glassy dacite from the 1915 eruption of Mt. Lassen in California, USA.Mt. Lassen is a large volcanic dome in the northern California portion of the Cascade Range, a sublinear chain of stratovolcanoes formed by subduction of the Juan de Fuca Plate underneath the North American Plate. The Cascade Range starts in northern California and extends into Oregon, Washington State, and into British Columbia.The black rocks shown here are from the 1915 eruption of Mt. Lassen. The rock is black porphyritic glassy dacite. The white spots are plagioclase feldspar phenocrysts. The black groundmass is mostly dacitic glass mixed with microphenocrysts of various minerals.Locality: Devastated Area, Lassen Volcano National Park, Cascade Range, northeastern California, USA |
| 撮影日 | 2010-07-14 18:37:08 |
| 撮影者 | James St. John |
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