Marble (Murphy Marble, Ordovician; quarry near Tate, Georgia, USA) 1 : 無料・フリー素材/写真
Marble (Murphy Marble, Ordovician; quarry near Tate, Georgia, 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 | Mable from the Ordovician of Georgia, USA. (7.6 centimeters across at its widest)Metamorphic rocks result from intense alteration of any previously existing rocks by heat and/or pressure and/or chemical change. This can happen as a result of regional metamorphism (large-scale tectonic events, such as continental collision or subduction), burial metamorphism (super-deep burial), contact metamorphism (by the heat & chemicals from nearby magma or lava), hydrothermal metamorphism (by superheated groundwater), shear metamorphism (in or near a fault zone), or shock metamorphism (by an impact event). Other categories include thermal metamorphism, kinetic metamorphism, and nuclear metamorphism. Many metamorphic rocks have a foliated texture, but some are crystalline or glassy.Marble is a common, crystalline-textured metamorphic rock composed of calcite (CaCO3 - calcium carbonate). It forms by intermediate- to high-grade metamorphism of limestone. Marble varies in color and crystal size, but is reliably identified by its crystalline texture, by bubbling in acid, and by not scratching glass (marble has a hardness of 3, while glass has a hardness of 5.5).The whitish-colored marble seen here was originally a Cambrian limestone. It was regionally metamorphosed during the Ordovician Taconic Orogeny.Geologic unit & age: Murphy Marble, OrdovicianLocality: commercial quarry near Tate, southern Pickens County, northern Georgia, USA |
| 撮影日 | 2015-03-21 22:49:28 |
| 撮影者 | James St. John |
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