Slickenlined normal fault in the Lowellville Shale (Pottsville Group, Lower Pennsylvanian; Beach City Dam outcrop, northeastern Ohio, USA) 2 : 無料・フリー素材/写真
Slickenlined normal fault in the Lowellville Shale (Pottsville Group, Lower Pennsylvanian; Beach City Dam outcrop, northeastern Ohio, USA) 2 / 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 | Slickenlined normal fault cutting through Pennsylvanian rocks in Ohio, USA."Lowellville Shale" is the nickname used here for dark-colored mudshales overlying the Lowellville Limestone in the Pottsville Group of northeastern Ohio, USA.Just above the Lowellville Limestone at the Beach City Dam outcrop, the Lowellville Shale is fissile to flaggy, fossiliferous, black calcareous shale. Above that is non-flaggy, sparsely-fossiliferous, incompetent, black calcareous shale. Observed fossils include Posidonia bivalves, Trepospira gastropods, crinoid stem columnals, straight-shelled nautiloid cephalopods, coiled cephalopods, plants, and horizontal burrows.The Lowellville Shale and underlying Lowellville Limestone are part of the Pottsville Group, 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 lineated surface shown above is a fault, a fracture in rocks along which differential displacement has occurred. Dip-slip faults are those involving movement of rocks in non-horizontal directions. The two common types of dip-slip faults are normal faults and reverse faults.This outcrop has a normal fault cutting through dark mudshales. Normal faults are the result of extensional stress, and involve downward movement of the hanging wall and upward movement of the footwall. The linear scratches are slickenlines, which are common on fault surfaces. They indicate the general trend of fault movement.Stratigraphy: Lowellville Shale, just above the Lowellville Limestone, Pottsville Group, upper Lower PennsylvanianLocation: Beach City Dam outcrop - exposure on the southern side of Sugar Creek, immediately downstream from Beach City Dam, northern Franklin Township, northwestern Tuscarawas County, northeastern Ohio, USA (40° 38’ 06.71” North latitude, 81° 33’ 21.80” West longitude) |
| 撮影日 | 2015-10-31 16:18:57 |
| 撮影者 | James St. John |
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