Fossiliferous intraclastic limestone (middle Boggs Limestone, middle Pottsville Group, lower Middle Pennsylvanian; subcrop in Symmes Creek, northern Muskingum County, eastern Ohio, USA) : 無料・フリー素材/写真
Fossiliferous intraclastic limestone (middle Boggs Limestone, middle Pottsville Group, lower Middle Pennsylvanian; subcrop in Symmes Creek, northern Muskingum County, eastern Ohio, USA) / 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 | Fossiliferous intraclastic limestone from the Pennsylvanian of eastern Ohio, USA. (6.7 cm across at its widest)The Pottsville Group is a Pennsylvanian-aged cyclothemic succession in eastern Ohio that contains nonmarine shales, marine shales, siltstones, sandstones, coals, marine limestones, and chert ("flint"). The lower Pottsville dates to the late Early Pennsylvanian. The upper part dates to the early Middle Pennsylvanian. The Lower-Middle Pennsylvanian boundary is apparently somewhere near the Boggs Member (?).The Boggs Member is a relatively thin stratigraphic interval. It typically consists of marine fossiliferous limestones, dominated by brachiopods and crinoid ossicles. Significant lateral lithologic variation is present - Boggs lithologies range from fossiliferous limestone to intraclastic limestone to ferruginous chert to "flint" to dolostone. In places, it has a relatively high component of disseminated pyrite. In other places, it is relatively rich in black manganese oxide(s).Minerals observed in the Boggs Limestone interval: calcite, dolomite, glauconite, goethite, gypsum, limonite, pyrite, sphalerite, turgite, vivianite, wad.This sample is from the middle part of the Boggs Limestone bed. It consists of fossiliferous limestone (dark lower part of the photo) with horizontally to subhorizontally oriented calcareous shell fragments plus crinoid ossicles. The middle and upper portions of the sample are intraclastic limestone - the clasts are a mix of limestone and dolostone. The yellowish-brown areas at the top of the specimen represent a thin ironstone crust of limonite and apparent goethite. The very bottom of the sample is coated with very dark brown-colored wad - more or less massive manganese oxide(s).Stratigraphy: middle Boggs Limestone, middle Pottsville Group, lower Atokan Stage, lower Middle PennsylvanianLocality: subaqueous outcrop in Symmes Creek, just east of Mollies Rock Road bridge (County Highway 40 bridge) & just east of the confluence with the North Branch of Symmes Creek, ~1.1 miles northeast of the Muskingum River, ~4 miles southeast of the town of Dresden, south-central Madison Township, northern Muskingum County, eastern Ohio, USA (40° 04.992’ North, 81° 57.186’ West) |
| 撮影日 | 2014-11-08 23:34:07 |
| 撮影者 | James St. John |
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