Gypsum molds in silicified metadolostone (Kona Dolomite, Paleoproterozoic, 2.2-2.3 Ga; Co. Rd. 480 roadcut, Ragged Hills, SW of Marquette, Upper Peninsula of Michigan, USA) 1 : 無料・フリー素材/写真
Gypsum molds in silicified metadolostone (Kona Dolomite, Paleoproterozoic, 2.2-2.3 Ga; Co. Rd. 480 roadcut, Ragged Hills, SW of Marquette, Upper Peninsula of Michigan, USA) 1 / 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 | Gypsum molds in weathered silicified metadolostone (Kona Dolomite, Paleoproterozoic, 2.2-2.3 billion years) from northern Michigan (Co. Rd. 480 roadcut, Ragged Hills, SW of Marquette, Upper Peninsula of Michigan, USA).------------Gypsum molds are empty spaces or secondarily-filled cavities (gypsum casts) in sedimentary rocks that match the monoclinic form of gypsum crystals (CaSO4·2H2O). They demonstrate that the original sediments were deposited in a supratidal evaporitic setting. Seawater-soaked sediments quickly dried out after the tides receded. Dissolved minerals in the water precipitated to form crystals in the sediments. In the case of the gypsum molds shown here, the original gypsum crystals dissolved away (gypsum is fairly soluble), leaving crystal-shaped gaps in the rock (originally a dolomitic mud). |
| 撮影日 | 2014-08-26 18:07:37 |
| 撮影者 | James St. John |
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