Shungite (Zaonezhskaya Formation, middle Paleoproterozoic, 1.98-2.09 Ga; Shun'ga River area, northwestern Russia) 4 : 無料・フリー素材/写真
Shungite (Zaonezhskaya Formation, middle Paleoproterozoic, 1.98-2.09 Ga; Shun'ga River area, northwestern Russia) 4 / James St. John
| ライセンス | クリエイティブ・コモンズ 表示 2.1 |
|---|---|
| 説明 | Shungite from the Precambrian of Russia. (~6.4 centimeters across at its widest)Shungite is a rare type of asphaltite from Russia. It is ~98% noncrystalline, non-graphitized carbon. It occurs in the upper Zaonezhskaya Formation, a Precambrian-aged platform succession of sedimentary rocks. In the unit, this unusual material occurs as stratiform shungite, diapiric shungite, redeposited clastic/detrital shungite, and vein shungite. The specific origin is uncertain - the literature refers to shungite as either pyrobitumen or Precambrian coal or carbonized hydrocarbons or highly-evolved bitumen.Shungite is black, glassy-textured, glassy-lustered, slightly lightweight for its size (= heavier than gilsonite from Utah), and has conchoidal fracture.The sample seen here is called "elite shungite" by rockhounds. Other shungite material has a dull luster and does not look like obsidian.Host unit: Zaonezhskaya Formation, Ludikovi Group, middle Paleoproterozoic, 1.98 to 2.09 Ga; greenschist-facies metamorphism at 1.8 GaLocality: unrecorded locality in the shungite mining field, northern Lake Onega area, southern Karelia Republic, south of the White Sea, southeastern Fennoscandian Shield, northwestern Russia |
| 撮影日 | 2019-08-29 21:35:07 |
| 撮影者 | James St. John |
| タグ | |
| 撮影地 |