Английская Википедия:Bedford Shale

The Bedford Shale is a shale geologic formation in the states of Ohio, Michigan, Pennsylvania, Kentucky, West Virginia, and Virginia in the United States.

Identification and name

John Strong Newberry, director of the Ohio State Geological Survey, first identified the formation in 1870.Шаблон:Sfn He called it the "Bedford Shale" and designated its type locality at Tinkers Creek Шаблон:Sfn near Bedford, Ohio.Шаблон:Sfn

Details of the type locality and of stratigraphic nomenclature for this unit as used by the U.S. Geological Survey are available on-line at the National Geologic Map Database.^[1]

The Bedford Shale in northern Ohio is a red, predominantly soft clay shale that grades to grayish-black near its base. Siltstone beds, showing ripples and some as much as Шаблон:Convert thick, are interbedded near the bottom.Шаблон:Sfn This red Bedford Shale consists mostly of sandstone and siltstone, and is much more argillaceous from mid-state Franklin County north-northeast to Lorain County on Lake Erie.Шаблон:Efn Proceeding east from Lorain County, the silt content increases. The Bedford undergoes a marked lithologic change at the Cuyahoga River. It becomes equal parts red and gray shale, and the basal Шаблон:Convert becomes a hard siltstone (the Euclid member, or Euclid siltstone). At Tinkers Creek in Bedford, Ohio, there is no red shale; instead there is about Шаблон:Convert of gray and bluish-gray shale, nodules of light-gray mudstone, and brownish-gray to gray irregular beds of siltstone. East of the Grand River, the clay shale is largely replaced by silty gray shale, hard silty gray mudstone, and thin platy gray siltstone.Шаблон:Sfn

The red shale fades in intensity and thickness toward the south. South of Columbus, the color fades to reddish-brown and exists only as a bed a few feet thick between bluish or bluish-gray Bedford Shale.Шаблон:Sfn The Bedford in southern Ohio is almost completely a bluish-gray shale.Шаблон:Sfn Proceeding south from Ross and Pike counties, the Bedford turns from a soft clay shale to a gray silty shale interbedded with thin beds of gray siltstone in its upper parts.Шаблон:Sfn In Ross, Pike, and Scioto counties, siltstone in the Bedford increases so much that it becomes mostly siltstone interbedded with silty shale.Шаблон:Sfn

Generally, the red Bedford thins and grades into the gray Bedford all along its margin.Шаблон:Sfn Along the rough line from Huron to Lawrence counties, beds of mudrock may be found.Шаблон:Sfn

Throughout Ohio, a few thin layers of siltstone may be found in all types of Bedford Shale. These are calcareous and Шаблон:Convert thick in central Ohio. Siltstone beds increase in number and thickness in the upper part of the Bedford shale south of Columbus. In southern Ross County, the upper third of the Bedford contains a large number of layers of thin, platy siltstoneШаблон:Sfn as well as occasional thin layers consisting of blebs of calcium carbonate, marcasite, and pyrite.Шаблон:Sfn Шаблон:Sfn Oscillation ripple marks can be seen on the upper surfaces of these siltstones.Шаблон:Sfn Silty laminae become common toward the bottom of the Bedford Shale throughout the state,Шаблон:Sfn as do thin beds of gray silty mudstone (a fine-grained type of mudrock).Шаблон:Sfn

"Flow rolls" are a structure which appears unique to the Bedford Shale. These structures appear in the basal part of the formation. In a flow roll, the rock is greatly deformed and rolled into a cylindrical shape.Шаблон:Sfn

The Bedford Shale of Michigan is a light grayШаблон:Sfn Шаблон:Sfn or bluish-light gray in color.Шаблон:Sfn Шаблон:Efn It is a silty shale,Шаблон:Sfn siltier and sandier in its upper part.Шаблон:Sfn The boundary with the Berea Sandstone exhibits thin veins ("stringers") of sandstone, indicating erosion of the Bedford Shale which was filled in later by sand.Шаблон:Sfn

The Bedford Shale appears gray or greenish-gray in Kentucky, and contains sparse to abundant thin beds of siltstone, calcareous concretions, and nodules of pyrite.Шаблон:Sfn Limited areas of red Bedford Shale can be found in Boyd County.Шаблон:Sfn Siltstone and sandstone beds are particularly common from LewisШаблон:Sfn and Greenup Шаблон:Sfn counties southeast to Pike County; here, the Bedford is referred to as the "Berea sand".Шаблон:Sfn Шаблон:Efn

Geographic Extent

The Bedford Shale is a shale geologic formation in the states of Ohio, Michigan, Pennsylvania, West Virginia, Ohio, and Virginia in the United States.

Ohio

Файл:Extent of Bedford Shale and Berea Sandstone - Ohio and N Kentucky.jpg

Map showing general location of the Bedford Shale in Ohio, northeastern Kentucky, and western Pennsylvania.

The Bedford Shale in Ohio has been extensively studied since 1943,Шаблон:Sfn and the 1954 study by Pepper, de Witt, and Demarest was still considered the classic study of the formation as late as 1991.Шаблон:Sfn

The Bedford Shale is present throughout much of Ohio.^[2]^[3] Outcrops extend along Lake Erie from the Ohio-Pennsylvania border west to Lorain County. It runs in a generally southern direction to Lawrence County in the south.Шаблон:Efn The southern border of Ohio along the Ohio River defines its southernmost boundary in the state. In eastern Meigs County, the boundary turns north and runs to north-central Athens County before turning northeast to run through western Washington County into Monroe County. It runs north through the center of Belmont and Jefferson counties, and in southern Columbiana County turns east to pass into Pennsylvania.Шаблон:Sfn

On average, the Bedford Shale in Ohio is Шаблон:Convert Шаблон:Sfn to Шаблон:Convert thick,Шаблон:Sfn reaching its maximum thicknessШаблон:Sfn between Huron and Lawrence counties.Шаблон:Sfn The shale is about Шаблон:Convert thick along its central ridge between Lorain and Licking counties. In northern Ohio, the thickness of the Bedford is irregular due to erosion prior to the deposit of the Berea Sandstone, and due to recent glacial and stream erosion. The Bedford thins toward the south; near Columbus in central Ohio it is Шаблон:Convert thick, and Шаблон:Convert near Chillicothe Шаблон:Convert to the south.Шаблон:Sfn It thins to the east as well, reaching Шаблон:Convert near Bedford and Шаблон:Convert in southwestern Ashtabula County.Шаблон:Sfn

Outcrops of the Bedford shale may be found throughout Cuyahoga, Lake, and Geauga counties in cliffs beneath the Berea sandstone. Outcrops are much fewer in Lorain County (west of Cuyahoga County). The Bedford appears only in deep valleys (such as those of rivers and large streams). The red shale weathers so swiftly into a sticky red mud that even these outcrops are usually covered by soil. South of the counties bordering Lake Erie, outcrops are usually covered by glacial drift. Occasional outcrops can be seen along streams that flow south into the Ohio River, particularly at Big Walnut Creek.Шаблон:Sfn

Michigan

Файл:Eastern North American Paleogeograpy Middle Devonian.png

Eastern North America in the Middle Devonian, showing the Michigan Basin of the Rheic Ocean.

In Michigan, the Bedford Shale is found in the southeast along shores of Lake Erie and Lake St. Clair; along the shore of Lake Huron north of Saginaw Bay; along the south shore of the Straits of Mackinac; north of 44 degrees latitude along the shore of Lake Michigan; and in the far southwest corner of the state.Шаблон:Sfn The Bedford Shale was first identified in Michigan in 1876 in the southeastern part of the state.Шаблон:Sfn Some sources say the shale is Шаблон:Convert thickШаблон:Sfn while others say it is generally about Шаблон:Convert thick.Шаблон:Sfn It is almost Шаблон:Convert thick in The Thumb of Michigan,Шаблон:Sfn and about Шаблон:Convert thick in Southeast Michigan.Шаблон:Sfn Шаблон:Efn The Bedford Shale becomes finer-grainedШаблон:Sfn and thins from Lake Erie/Lake St. Clair to the west,Шаблон:Sfn pinching out to extinction near the center of the Michigan Basin and merging with the upper part of the Ellsworth Shale.Шаблон:Sfn In south-central Michigan, the Bedford Shale grades into and intertongues with the Antrim Shale.Шаблон:Sfn

There are no known outcrops of the Bedford Shale in Michigan,Шаблон:Sfn as it and the rocks above it are covered by Pleistocene glacial drift.Шаблон:Sfn

Kentucky

The Bedford Shale is present throughout much of eastern Kentucky.^[4]Шаблон:Sfn It is thickest in north (in Lewis County), thinning out to extinction in Bath,Шаблон:Sfn Estill, and Pike countiesШаблон:Sfn Шаблон:Efn as it proceeds south and west.Шаблон:Sfn It is about Шаблон:Convert thick in Letcher and Pike counties,Шаблон:Sfn which were closest to the Famennian deltas being deposited from the east and southeast.Шаблон:Sfn The Bedford Shale essentially forms a great wedge underground, with the narrow edge in the southwest.Шаблон:Sfn

The Bedford Shale in Kentucky is covered in thin soil and heavily weathered sandstone blocks.Шаблон:Sfn Outcrops of the rock may be seen along the Pine Mountain ridge in Harlan County.Шаблон:Sfn In Kentucky, a transition zone ranging from a few inches to Шаблон:Convert in thickness occasionally appears as the basal member of the Bedford Shale.

Pennsylvania

Bedford Shale is found in Crawford County, Pennsylvania, where it is also known as "Hayfield limestone". It is extremely lenticular and highly localized,Шаблон:Sfn and gray to bluish-gray in color.Шаблон:Sfn It is frequently interbedded with ripple markedШаблон:Sfn siltstone,Шаблон:Sfn and contains a few thin siliceous limestone layers. It overlays the Cussewago Sandstone and is overlain by the Berea Sandstone. The Bedford is Шаблон:Convert feet at Littles Corners in Hayfield Township, and decreases to Шаблон:Convert thick Шаблон:Convert northwest of Meadville. It thins rapidly and loses its identity around Meadville,Шаблон:Sfn where it grades into the Shellhammer Hollow Formation.Шаблон:Sfn Fucoids in the shale can be seen on Stratton Creek.Шаблон:Sfn

West Virginia

The Bedford Shale has also been traced into West Virginia. It may be found in the subsurface along the Ohio River in Mason, Cabell, Wayne, and Mingo counties. Its edge cannot be readily determined, as the Bedford's gray shale and interbedded siltstones overlay extremely similar Early Famennian rocks. However, the Bedford Shale appears to pinch out in southern Mingo County.Шаблон:Sfn The Bedford Shale may exist in northern West Virginia, but had not been identified there as of 1979.Шаблон:Sfn

Virginia

Bedford Shale has also been identified in the Dickenson-Buchanan county area in southwestern Virginia.Шаблон:Sfn

Stratigraphic Setting

The Bedford Shale is the basal member of the Waverly Group, which (in ascending order) includes the Bedford Shale, Berea Sandstone, Sunbury Shale, Cuyahoga Formation, Logan Formation, and the Maxville Limestone.Шаблон:Sfn

Generally, the Bedford Shale in Ohio is underlain by the Cleveland Shale throughout most of Ohio,Шаблон:Sfn although it is underlain by the Chagrin Shale in the east.Шаблон:Sfn The boundary with the Cleveland Shale is usually clear.Шаблон:Sfn However, a transition zone, ranging from a few inches to Шаблон:Convert in thickness, occasionally appears. The transition zone is missing along most of the western edge of the red Bedford Shale in northern Ohio, and only at a few places are thin stringers of black shale found in the basal part of the Bedford.Шаблон:Sfn Above the transition layer, there is usually about Шаблон:Convert of gray shale. This represents the basal part of the Bedford Shale. This gray shale thickens significantly east of Cuyahoga River, and to the south as the red shale pinches out.Шаблон:Sfn It is difficult to impossible to visually determine the boundary with the Chagrin Shale due to its lithologic similarity with the Bedford. In eastern Ashtabula and Trumbull counties, the Bedford overlays the Cussewago Sandstone.Шаблон:Sfn

The Bedford Shale is generally overlaid by the Berea Sandstone throughout Ohio.Шаблон:Sfn The contact between the two is generally clear but extremely irregular. Шаблон:Sfn Pre-Berea and Berean erosion eroded significant portions of the red Bedford Shale in northern Ohio.Шаблон:Sfn For example, near Berea, Ohio, Шаблон:Convert deep channels were scoured into the Bedford Shale. Sand filled these channels, and became Berea Sandstone.Шаблон:Sfn To the southwest, in Huron County, these channels cut down to the Cleveland Shale. Along Ohio's eastern border, in Columbiana, Mahoning, and Trumbull counties, erosion has almost completely removed the Bedford Shale. Erosional channeling becomes less marked toward the south-central Ohio. Near Columbus, the channels are only about Шаблон:Convert deep, and they disappear south of Lithopolis (which is Шаблон:Convert southeast of Columbus).Шаблон:Sfn In southern Ohio, the Bedford and Berea grade into one another so gradually that the boundary between them cannot be distinguished visually.Шаблон:Sfn

The Bedford Shale in Michigan is generally overlaid by the Berea Sandstone. The upper part of Bedford in this state is silty and sandy,Шаблон:Sfn making the boundary between it and the Berea sandstone nearly impossible to identify visually. The boundary may be determined by gamma ray logging, however.Шаблон:Sfn In eastern Michigan, the Bedford Shale overlays the Antrim Shale.Шаблон:Sfn Шаблон:Sfn Toward the center of the Michigan Basin, the Bedford overlays the Ellsworth Shale. The boundary between the two becomes increasingly difficult to identify as one proceeds west, as the Bedford merges laterally into the upper Шаблон:Convert of the Ellsworth Shale.Шаблон:Sfn

In the vicinity of Irvine (Michigan), the black shale of the Sunbury comes in contact with the black shale of the Ohio shale as a result of the feathering out of the Berea and Bedford strata. Шаблон:Sfn

Generally,Шаблон:Sfn the Bedford Shale in Kentucky is underlain by the Ohio ShaleШаблон:Sfn and overlaid by the Berea Sandstone.Шаблон:Sfn The Bedford Shale's upper and lower contacts are usually sharp in the state, but complicated by intense deformation.Шаблон:Sfn In much of eastern Kentucky,Шаблон:Sfn the Bedford Shale and Berea Sandstone intertongue (interlock).Шаблон:Sfn Near Vanceburg, the upper Шаблон:Convert of the Bedford Shale is silty shale that comes between the Bedford and Berea siltstone. Only Шаблон:Convert to the east near Garrison, Bedford is almost completely siltstone. Just Шаблон:Convert south, near Petersville, the Bedford has almost no siltstone layer. There are only a few thin siltstone beds present, and the Bedford grades almost imperceptibly into the Berea—both of which are composed of bluish-gray to gray clay shales and some gray silty shale. In southern Lewis County, there is no Bedford siltstone; the upper portion of the Bedford is a noticeably soft bluish-gray shale.Шаблон:Sfn Near Olympia in Bath County, the Berea Sandstone is not found and the Sunbury Shale overlies the Bedford,Шаблон:Sfn while near Irvine in Estill County to the south both the Berea and Bedford are missing and the Sunbury lies atop the Ohio Shale.Шаблон:Sfn

Fossils

Except for its lowest strata, the Bedford Shale is largely fossil-free. In central and north-central Ohio, the Bedford Shale contains extensive fossils in the first few feet of its bottommost part. These include brachiopods like Lingula, Orbiculoidea, and the large Syringothyris bedfordensis; molluscs, particularly bivalves;Шаблон:Sfn and Devonian fish.Шаблон:Sfn South of Ross County, most of the siltstones in the Bedford Shale show fucoids (casts of Fucales, a common littoral seaweed).Шаблон:Sfn

The basal Шаблон:Convert of the Bedford Shale in Michigan contains extensive fossils of the Famennian stage.Шаблон:Sfn Small amounts of natural gas have been recovered from the shale as well.Шаблон:Sfn

In Kentucky, a transition zone ranging from a few inches to Шаблон:Convert in thickness occasionally appears as the basal member of the Bedford Shale in Kentucky. Invertebrate fossils are found at the top of this transition zone in northeast Kentucky.Шаблон:Sfn

Age

Although there have been conflicting reports in the past, the most recent evidence is that the rock was laid down very late in the Famennian stage of the Devonian period. This makes the rock about 365 to 358.9 million years old. The age of the Bedford Shale has seen significantly different interpretations over time. Some geologists have placed it exclusively in the upper DevonianШаблон:Sfn Шаблон:Sfn Шаблон:Sfn while others have concluded it is exclusively lower Carboniferous.Шаблон:Sfn Шаблон:Sfn Шаблон:Sfn Still others have placed the Devonian-Carboniferous boundary in the basal few inches or feet of the Bedford Shale.Шаблон:Sfn Шаблон:Sfn Шаблон:Sfn Шаблон:Sfn Шаблон:Sfn Depending on the source, the rock began to be laid down either 360 million years agoШаблон:Sfn or 365 million years ago.Шаблон:Sfn and finished being laid down at the end of the Famennian 358.9 million years ago.Шаблон:Sfn Шаблон:Efn

In their 1991 review of the literature, geologists Raymond C. Gutschick and Charles A. Sandberg point out that the Bedford Shale is correctly assigned to the upper Devonian. The 1975 Devonian-Carboniferous Boundary Working Group of the International Union of Geological Sciences engaged in an extensive study of brachiopod, conodont, and spore fossils in the Bedford Shale and Berea Sandstone, and found no evidence of lower Mississippian conodonts in either rock formation.Шаблон:Sfn The American definition of the Devonian period was realigned to match the definition already in use in Europe, which led to the placement of both formations in the Famennian stage of the upper Devonian.Шаблон:Sfn

Interpretation of Depositional Environment

The Bedford Shale was laid down by several river deltas. One delta laid down this rock formation in Michigan's Thumb peninsula. Several small deltas deposited Bedford Shale in Kentucky. A particularly large delta, known as the Red Bedford Delta, laid down a red-colored wedge of the shale in central Ohio.

The climate of the late Famennian was mild, and much plant life grew along streams and rivers. There was abundant precipitation, and monsoons swept the area from west to east.Шаблон:Sfn

During the Famennian stage of the late Devonian period, the Rheic Ocean covered much of what is now Kentucky, Michigan, and Ohio in the United States.Шаблон:Sfn This sea became extremely cloudy and turned anoxic (oxygen-poor) during the Hangenberg event, a global extinction that marked the end of the Devonian period and which deposited large amounts of erosion sediment and organic material into the sea.Шаблон:Sfn After the Hangenberg event ended, the waters of the Rheic Ocean began to clear and oxygenate again. The end of the Hangenberg event coincided with the end of the Acadian orogeny, a highly active period of mountain-building that began in the middle Devonian and created the Acadian Mountains which covered the Mid-Atlantic region, New England, and the Canadian Maritimes.Шаблон:Sfn As sea levels fell, the Canadian Shield and the Acadian Mountains began to erode. Material from these areas created river deltas that pushed south and west into the sea, creating the Bedford Shale and Berea Sandstone.Шаблон:Sfn Шаблон:Efn

Файл:Ontario Paleoriver and the Bedford Shale.jpg

A sketch map of the paleo Ontario River system

The Ohio Bay of the Rheic Ocean covered most of Kentucky, Michigan, Ohio, and western Pennsylvania, Virginia, and West Virginia.Шаблон:Sfn At the start of the period during which the Bedford Shale began to be laid, muddy waters of the bay began to clear. The land adjacent to the north and east rose, furnishing coarser detrital material. Stronger currents stirred up the mud, which mixed with the coarse sediment and became the basal part of the Bedford Shale. The stronger current oxygenated the water, and small mollusks and fish repopulated the bay. Greater amounts of sediment flowing into the bay made it inhospitable for life again.Шаблон:Sfn Шаблон:Sfn The shallow sea kept rising, reaching its maximum depth when about half the Bedford Shale had been deposited. The sea rose and fell repeatedly while the remainder of the Bedford was deposited.Шаблон:Sfn Шаблон:Efn

The ancient Ontario River probably entered the Ohio Bay about Lorain County,Шаблон:Sfn depositing red sediment which originated in the eastern part of the Canadian Shield.Шаблон:Sfn Шаблон:Sfn This created the Red Bedford Delta which deposited the sediment that became the red Bedford Shale of north-central and northeast Ohio.Шаблон:Sfn In time, the Red Bedford Delta extended about Шаблон:Convert south into the Ohio Bay,Шаблон:Sfn nearly dividing it.Шаблон:Sfn The pre-erosion delta was roughly Шаблон:Convert wide at its northern end, Шаблон:Convert wide in the middle, and about Шаблон:Convert wide at its southern end. Two lobes, each about Шаблон:Convert wide, extended from the southern tip.Шаблон:Sfn Oscillation ripple marks in the siltstone of the Bedford Shale's gray basal part shows that this sediment was deposited under water.Шаблон:Sfn Шаблон:Efn These ripple marks are not present in the red Bedford Shale, indicating it was deposited subaerially. There is also a well-documented system of about Шаблон:Convert of ancient braided and meandering water channels in Ashland, Holmes, and Knox counties, indicating where the distributary network of the river sought to reach the sea.Шаблон:Sfn

The Cincinnati Arch and its branches, the Findlay Arch and the Kankakee Arch, probably prevented the red sediment from reaching westward.Шаблон:Sfn This vast arc of rock, which extends from western Alabama and northern Mississippi northeast to north-central Ohio, was probably a low-lying island near Cincinnati, Ohio, when the Bedford Shale first began to be laid down. It not only rose over the next several million years, it accreted sediment to it—perhaps extending almost to the northern shore of the Ohio Bay.Шаблон:Sfn

The ancient Gay-Fink River, Cabin Creek River, and Virginia-Carolinas River also formed large deltas in the eastern part of the Ohio Bay, contributing gray sedimentary material to the Bedford ShaleШаблон:Sfn from what is now Virginia, North Carolina, and South Carolina.Шаблон:Sfn As much as one-fifth of the total area of the Bedford Shale was created from these deltas.Шаблон:Sfn

A number of sandbars, collectively known as the Channel Sands,Шаблон:Sfn existed on either side of what later became the Red Bedford Delta.Шаблон:Sfn These irregularly shaped bodies continue to exist within the Bedford Shale. One such narrow, sinuous, branching body exists in a Шаблон:Convert line from Richland County south to Hocking County. Smaller sand bodies exist in Ames Township in Athens County, Reading Township in Perry County, and a few other places. These sand bodies all lie beneath the red shale, indicating they were laid down early in the Bedford Shale's depositional history.Шаблон:Sfn

Two large siltstone lentils were created during the deposition of the Bedford Shale, the northern Sagamore and the southern Euclid.Шаблон:Sfn The Sagamore, which has a maximum thickness of Шаблон:Convert, is found on Sagamore Creek in southeastern Cuyahoga County, and is in the lower third of the Bedford Shale.Шаблон:Sfn The Euclid, which has a maximum thickness of Шаблон:Convert, extends from Independence, Ohio northeast to Willoughby, Ohio, and is part of the most basal member of the Bedford Shale.Шаблон:Sfn

An extremely large sandstone lens is the Second Berea. Located in Athens, Gallia, Meigs, Morgan, and Muskingum counties, this sandstone body is Шаблон:Convert long and Шаблон:Convert wide. Originally known as the "stray gas sand", it was originally a large sandbar east of what became the Red Bedford Delta. It is equivalent in age to the Euclid siltstone. About Шаблон:Convert of gray Bedford Shale overlays the Second Berea.Шаблон:Sfn

As in other states, the Bedford Shale in Michigan was deposited by deltas.Шаблон:Sfn Шаблон:Sfn Relatively coarse clastic materialШаблон:Sfn eroded from the Canadian ShieldШаблон:Sfn was carried by the ancient Ontario River System south into the Michigan Basin of the Rheic Ocean. There, the sediment was deposited to the south and west by the Thumb Delta, a large delta which at that time covered The Thumb of Michigan.Шаблон:Sfn There is good evidence to suggest that Bedford Shale in Michigan was not laid down contemporaneously with the red Bedford Shale in Ohio, and most likely came shortly after.Шаблон:Sfn Although the Michigan Basin and the Appalachian Basin were connected, later tectonic uplift created the Findlay Arch.Шаблон:Sfn As younger rock atop the arch eroded, a Шаблон:Convert gap was created between the Bedford Shale of Ohio and the Bedford Shale of Michigan.Шаблон:Sfn

As in other states, the Bedford Shale in Kentucky was formed by deltas.Шаблон:Sfn The shale exhibits cross-bedding and erosional channels filled with Berea Sandstone, both of which indicate that the Rheic Sea was shallow.Шаблон:Sfn Three ancient rivers—the Gay-Fink, the Cabin Creek, and the Virginia-Carolina—probably deposited most of the sediment,Шаблон:Sfn which consisted of detrital rock and organic matter from the Acadian Mountains flowing westward and southwardШаблон:Sfn into the shallow sea covering the Appalachian Basin.Шаблон:Sfn Evidence for a westerly and southwesterly flow of water comes from channels eroded in the shale and filled with sandstone. These lobes extend southwest, indicating the direction of the flow of water. Ripple marks in the Bedford Shale in Kentucky form in a northwest–southeast line, indicating a steady wind coming from the northeast.Шаблон:Sfn

Economic Resources

Native Americans used heavily weathered Bedford Shale for its reddish pigment. Colonial French traders named Vermillion River after the Bedford's red shale.Шаблон:Sfn Weathered Bedford Shale was also used in the 1800s and early 1900s to make face brick (a brick used on exterior surfaces to present a clean appearance) and tile.Шаблон:Sfn

References

Notes

Шаблон:Notelist

Citations

Шаблон:Reflist

Bibliography

Шаблон:Refbegin

Шаблон:Refend

Шаблон:Chronostratigraphy of Kentucky Шаблон:Stratigraphic column of Michigan Шаблон:Chronostratigraphy of Ohio Шаблон:Stratigraphic column of Pennsylvania Шаблон:Stratigraphic column of Virginia Шаблон:Stratigraphic column of West Virginia

↑ Шаблон:Cite web
↑ Ryder, R.T., Crangle, R.D., Jr., Trippi, M.H., Swezey, C.S., Lentz, E.E., Rowan, E.L., and Hope, R.S., 2009, Geologic cross section D-D' through the central Appalachian basin from the Findlay arch, Sandusky County, Ohio, to the Valley and Ridge province, Hardy County, West Virginia: U.S. Geological Survey Scientific Investigations Map SIM-3067, 2 sheets with 52-page pamphlet. http://pubs.er.usgs.gov/publication/sim3067
↑ Ryder, R.T., Trippi, M.H., Swezey, C.S., Crangle, R.D., Jr., Hope, R.S., Rowan, E.L., and Lentz, E.E., 2012, Geologic cross section C-C' through the central Appalachian basin from near the Findlay Arch, north-central Ohio, to the Valley and Ridge Province, Bedford County, south-central Pennsylvania: U.S. Geological Survey Scientific Investigations Map SIM-3172, 2 sheets with 70-page pamphlet. http://pubs.er.usgs.gov/publication/sim3172
↑ Ryder, R.T., Trippi, M.H., and Swezey, C.S., 2015, Geologic cross section I-I' through the central Appalachian basin from north-central Kentucky to southwestern Virginia: U.S. Geological Survey Scientific Investigations Map SIM-3343, 2 sheets with two pamphlets (41p. and 102p.). http://pubs.er.usgs.gov/publication/sim3343

[1] Шаблон:Cite web

[2] Ryder, R.T., Crangle, R.D., Jr., Trippi, M.H., Swezey, C.S., Lentz, E.E., Rowan, E.L., and Hope, R.S., 2009, Geologic cross section D-D' through the central Appalachian basin from the Findlay arch, Sandusky County, Ohio, to the Valley and Ridge province, Hardy County, West Virginia: U.S. Geological Survey Scientific Investigations Map SIM-3067, 2 sheets with 52-page pamphlet. http://pubs.er.usgs.gov/publication/sim3067

[3] Ryder, R.T., Trippi, M.H., Swezey, C.S., Crangle, R.D., Jr., Hope, R.S., Rowan, E.L., and Lentz, E.E., 2012, Geologic cross section C-C' through the central Appalachian basin from near the Findlay Arch, north-central Ohio, to the Valley and Ridge Province, Bedford County, south-central Pennsylvania: U.S. Geological Survey Scientific Investigations Map SIM-3172, 2 sheets with 70-page pamphlet. http://pubs.er.usgs.gov/publication/sim3172

[4] Ryder, R.T., Trippi, M.H., and Swezey, C.S., 2015, Geologic cross section I-I' through the central Appalachian basin from north-central Kentucky to southwestern Virginia: U.S. Geological Survey Scientific Investigations Map SIM-3343, 2 sheets with two pamphlets (41p. and 102p.). http://pubs.er.usgs.gov/publication/sim3343

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Партнерские ресурсы
Криптовалюты	Обмен криптовалют - www.bestchange.ru Криптовалютная биржа CoinEx Криптовалютная биржа Binance HIVE OS - операционная система для майнинга e4pool - Мультивалютный пул для майнинга.
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