Angular unconformity (basalt lava flow over redbeds; St. George, Utah, USA) 3 : 無料・フリー素材/写真
Angular unconformity (basalt lava flow over redbeds; St. George, Utah, USA) 3 / 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 | Unconformities are surfaces of erosion and/or non-deposition of sediments. The erosion surface seen here is an angular unconformity, with horizontal layers above and tilted layers below. The dark rocks at top are part of the Middleton Flow, a quartz-bearing andesitic basalt lava flow erupted during the Pleistocene. The rocks below are redbeds in the Mesozoic-aged Kayenta Formation. The angular unconformity is this case is a bit subtle - the Kayenta beds are slightly tilted (click on the photo once or twice to zoom in).Stratigraphy: Middleton Flow (Pleistocene, ~1.5 Ma) over the middle member of the Kayenta Formation (Upper Triassic to Lower Jurassic)Locality: Middleton Black Ridge, St. George, Washington County, southwestern Utah, USA |
| 撮影日 | 2010-07-05 20:18:17 |
| 撮影者 | James St. John |
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