Delaware Limestone over Columbus Limestone (Middle Devonian; Indian Village Canyon, Columbus, Ohio, USA) 1 : 無料・フリー素材/写真
Delaware Limestone over Columbus Limestone (Middle Devonian; Indian Village Canyon, Columbus, Ohio, 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 | Limestones in the Devonian of Ohio, USA.The thick-bedded limestones in the lower half of the photo are part of the Columbus Limestone, a significant carbonate unit in the Devonian of central and northern Ohio. It's actually part of a much more widespread sheet of Devonian carbonates that extends from New York State to America's Midwest. The Columbus Limestone represents deposition in a subtropical, shallow-water, carbonate platform environment. The rocks are principally micritic limestones, fossiliferous wackestones, and fossiliferous packstones. Some chert nodules are present in the unit. Fossils are typical Paleozoic shallow marine invertebrates - favositid corals, rugose corals, stromatoporoids, brachiopods, crinoids, blastoids, bryozoans, trilobites, bivalves, gastropods, cephalopods, rostroconchs, and tentaculites. Microfossils include conodonts and charophyte oogonia. Other fossils in the Columbus Limestone include vertebrates (fish), land plants (rare), and trace fossils. Some fossil horizons in the Columbus Limestone are partially silicified.The thin-bedded limestones in the upper half of the photo are part of the Delaware Limestone. The contact is a prominent disconformity (a type II sequence boundary). Biostratigraphic studies have shown that one conodont biozone is missing at the Columbus-Delaware contact in central Ohio, probably representing ~1 to 3 million years. The base of the Columbus Limestone (not visible here) is a major, continent-wide unconformity representing the Tippecanoe-Kaskaskia megasequence boundary (a type I sequence boundary).Stratigraphy: uppermost Columbus Limestone & lowermost Delaware Limestone, Eifelian Stage, lower Middle DevonianLocality: creek cut on the northern side of Indian Village Canyon, Duranceau City Park, western side of Columbus, Franklin County, central Ohio, USA |
| 撮影日 | 2021-12-17 10:57:40 |
| 撮影者 | James St. John |
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