Broad Top is a
plateau
In geology and physical geography, a plateau (; ; ), also called a high plain or a tableland, is an area of a highland consisting of flat terrain that is raised sharply above the surrounding area on at least one side. Often one or more sides ha ...
located in south-central
Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...
. It extends into
Huntingdon County
Huntingdon is a market town in the Huntingdonshire district in Cambridgeshire, England. The town was given its town charter by John, King of England, King John in 1205. It was the county town of the historic county of Huntingdonshire. Oliver Cr ...
to the north,
Fulton County Fulton County is the name of eight counties in the United States of America. Most are named for Robert Fulton, inventor of the first practical steamboat:
*Fulton County, Arkansas, named after Governor William Savin Fulton
*Fulton County, Georgia
*F ...
to the southeast, and
Bedford County to the southwest. It is bounded to the west by Saxton Mountain and Terrace Mountain, and to the east by
Sideling Hill
Sideling Hill, also Side Long Hill, is a long, steep, narrow mountain ridge in the Ridge-and-Valley (or Allegheny Mountains) physiographic province of the Appalachian Mountains, located in Washington County in western Maryland and adjacent West ...
. In Bedford County, Harbor Mountain forms the southern boundary. Trough Creek Valley lies between the mountains.
State Lands
Pennsylvania State Game Lands The Pennsylvania State Game Lands (SGL) are lands managed by the Pennsylvania Game Commission (PGC) for hunting, trapping, and fishing. These lands, often not usable for farming or development, are donated to the PGC or purchased by the PGC with hu ...
67, 121, and 267 lie on Broad Top. Part of
Rothrock State Forest
Rothrock State Forest is a Pennsylvania state forest in Pennsylvania Bureau of Forestry District #5. The main offices are located in Huntingdon in Huntingdon County, Pennsylvania in the United States.
Rothrock State Forest is located in Centre, ...
lies on Broad Top as well, as is most of
Trough Creek State Park
Trough Creek State Park is a Pennsylvania state park in Cass, Penn and Todd Townships, Huntingdon County, Pennsylvania in the United States. The majority of the park is in Todd Township along Pennsylvania Route 994, east of the unincorporat ...
in
Huntingdon County
Huntingdon is a market town in the Huntingdonshire district in Cambridgeshire, England. The town was given its town charter by John, King of England, King John in 1205. It was the county town of the historic county of Huntingdonshire. Oliver Cr ...
.
Geology
The bedrock of Broad Top consists of relatively flat-lying
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiĆ³s'' (, "old") and ' ...
sedimentary
Sedimentary rocks are types of rock (geology), rock that are formed by the accumulation or deposition of mineral or organic matter, organic particles at Earth#Surface, Earth's surface, followed by cementation (geology), cementation. Sedimentati ...
rocks that are
stratigraphically higher, and thus younger than the rocks immediately surrounding the plateau. Mapped formations on the plateau include the
Mississippian-
Devonian
The Devonian ( ) is a geologic period and system of the Paleozoic era, spanning 60.3 million years from the end of the Silurian, million years ago (Mya), to the beginning of the Carboniferous, Mya. It is named after Devon, England, whe ...
Rockwell Formation
The Rockwell Formation is a late Devonian and early Mississippian mapped bedrock unit in West Virginia, Maryland, and Pennsylvania, in the United States.
Description
The Rockwell Formation was described at its type section at Rockwell Run in We ...
, the
Mississippian Pocono Formation
The Mississippian Pocono Formation is a mapped bedrock unit in Pennsylvania, Maryland, and West Virginia, in the United States. It is also known as the Pocono Group in Maryland and West Virginia,
and the upper part of the Pocono Formation is somet ...
and
Mauch Chunk Formation
The Mississippian Mauch Chunk Formation is a mapped bedrock unit in Pennsylvania, Maryland, and West Virginia. It is named for the township of Mauch Chunk, now known as borough of Jim Thorpe, Pennsylvania and for nearby Mauch Chunk Ridge where th ...
, and the
Pennsylvanian Pottsville Group
The Pennsylvanian Pottsville Formation is a mapped bedrock unit in Pennsylvania, western Maryland, West Virginia, Ohio, and Alabama. It is a major ridge-former in the Ridge-and-Valley Appalachians of the eastern United States. The Pottsville Fo ...
,
Allegheny Formation
The Pennsylvanian Allegheny Formation is a mapped bedrock unit in western and central Pennsylvania, western Maryland and West Virginia, and southeastern Ohio. It is a major coal-bearing unit in the Appalachian Plateau of the eastern United States ...
, and Conemaugh Group.
[Map 61: Atlas of Preliminary Geologic Quadrangle Maps of Pennsylvania, compiled and edited by Thomas M. Berg and Christine M. Dodge, 1981, Pennsylvania Geologic Survey, 4th Series, Harrisburg, PA (Saxton Quadrangle, Wells Tannery Quadrangle, Entriken Quadrangle, Cassville Quadrangle, Saltillo Quadrangle, Huntingdon Quadrangle, Mount Union Quadrangle)]
Although Broad Top lies within the
Ridge and Valley Physiographic Province, it is actually more similar to the Allegheny Plateau due to its flat-lying rocks and stratigraphic similarity to rocks there.
Bituminous
Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term a ...
coal
Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen.
Coal is formed when dea ...
has been mined in the Broad Top area, and the coal field is known as the Broad Top Field. Nearly all of the coal lies within the
Allegheny Formation
The Pennsylvanian Allegheny Formation is a mapped bedrock unit in western and central Pennsylvania, western Maryland and West Virginia, and southeastern Ohio. It is a major coal-bearing unit in the Appalachian Plateau of the eastern United States ...
PA Geologic Survey Map 11. Abandoned mines exist in the area and
acid mine drainage
Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines or coal mines.
Acid rock drainage occurs naturally within some environments as part of the rock weathering ...
is an environmental problem, where several fishless streams exist as a result of the discharge from the abandoned mines
References
{{coord missing, Pennsylvania
Landforms of Pennsylvania
Plateaus of the United States