| 词条 | Brallier Formation |
| 释义 |
| name = Brallier Formation | image = Brallier Formation PA Turnpike MM138.JPG | caption = Outcrop of Brallier Formation on north side of Pennsylvania Turnpike, central Bedford County, near Mile Marker 138 | type = sedimentary | age = Frasnian - Famennian[1] | period = Late Devonian | prilithology = shale, sandstone | otherlithology = | namedfor = | namedby = Charles Butts, 1918[2] | region = Appalachian Mountains | country = United States | coordinates = | unitof = | subunits = Black Creek Siltstone Member,[3] Minnehaha Springs Member[4] | underlies = Greenland Gap Group and Scherr Formation | overlies = Harrell Formation | thickness = 1350 to 1800 feet in central PA[2] | extent = Maryland, Pennsylvania, Virginia, and West Virginia | area = | map = | map_caption = }} The Devonian Brallier Formation is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia. DescriptionThe Brallier Formation was described by Charles Butts in 1918 as a fine-grained, siliceous shale with few fine-grained sandstone layers, from outcrops in central Pennsylvania. Others expanded usage of the term to rocks in other states. StratigraphyThe Brallier is roughly equivalent to the Scherr Formation. The contact with the underlying Harrell Formation is generally gradational. FossilsHasson and Dennison reported the following fossils from outcrops of the lower Brallier at Keyser, West Virginia, Ridgeville, West Virginia, and McCoole, Maryland:[5]
Notable ExposuresType locality is at a railway station 6 miles northeast of Everett, Bedford County, Pennsylvania.[2] A large exposure is located in Huntingdon, Pennsylvania, along the ramp from U.S. Route 22 west to Route 26 north. AgeRelative age dating places the Brallier in the late Devonian. References1. ^[https://vtechworks.lib.vt.edu/bitstream/handle/10919/19078/Read%20and%20Eriksson.pdf?sequence=1 Paleozoic Sedimentary Successions of the Virginia Valley & Ridge and Plateau] {{Chronostratigraphy of Maryland}}{{Chronostratigraphy of Pennsylvania}}{{Chronostratigraphy of Virginia}}{{Stratigraphic column of West Virginia}}{{Clear}}{{US-geologic-formation-stub}}2. ^1 2 Butts, Charles, 1918, Geologic section of Blair and Huntingdon Counties, central Pennsylvania: American Journal of Science, 4th series, v. 46, p. 523-537. 3. ^Avary, K.L., and Dennison, J.M., 1980, Back Creek Siltstone Member of Devonian Brallier Formation in Virginia and West Virginia: Southeastern Geology, v. 21, no. 2, p. 121-153. 4. ^Lyke, W.L., 1986, The stratigraphy, paleogeography, depositional environment, faunal communities, and general petrology of the Minnehaha Springs Member of the Scherr Formation: Southeastern Geology, v. 26, no. 3, p. 173-192. 5. ^Hasson, Kenneth O., and Dennison, John M., 1978, STRATIGRAPHY OF THE DEVONIAN HARRELL AND MILLBORO SHALES IN PARTS OF PENNSYLVANIA, MARYLAND, WEST VIRGINIA, AND VIRGINIA, Project Final Report for Energy Research and Development Administration Contract #EY-77-C-21-8153, May 1978 8 : Devonian System of North America|Shale formations of the United States|Devonian Maryland|Devonian geology of Pennsylvania|Devonian geology of Virginia|Devonian West Virginia|Frasnian Stage|Famennian |
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