Pocono Formation
Encyclopedia
The Mississippian Pocono Formation (Mp) is a mapped bedrock unit in Pennsylvania
, Maryland
, and West Virginia
, USA. It is also known as the Pocono Group in Maryland and West Virginia,
and the upper part of the Pocono Formation is sometimes called the Burgoon Formation or Burgoon Sandstone in Pennsylvania.
The Pocono is a major ridge-former In the Ridge-and-Valley Appalachians
of the eastern United States
The Pocono is also a lateral equivalent of the Purslane Sandstone in Maryland and West Virginia. D. Brezinski of Maryland Geological Survey recommended abandoning use of the term Pocono in Maryland in favor of "Purslane" in 1989.
medium to coarse-grained sandstones. The base of the Pocono Formation is marked by conglomerate
.
. In South-central Pennsylvania, the Pocono often interfingers with the Rockwell Formation
.
Pennsylvania
The Commonwealth of Pennsylvania is a U.S. state that is located in the Northeastern and Mid-Atlantic regions of the United States. The state borders Delaware and Maryland to the south, West Virginia to the southwest, Ohio to the west, New York and Ontario, Canada, to the north, and New Jersey to...
, Maryland
Maryland
Maryland is a U.S. state located in the Mid Atlantic region of the United States, bordering Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware to its east...
, and West Virginia
West Virginia
West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...
, USA. It is also known as the Pocono Group in Maryland and West Virginia,
and the upper part of the Pocono Formation is sometimes called the Burgoon Formation or Burgoon Sandstone in Pennsylvania.
The Pocono is a major ridge-former In the Ridge-and-Valley Appalachians
Ridge-and-valley Appalachians
The Ridge-and-Valley Appalachians, also called the Ridge and Valley Province or the Valley and Ridge Appalachians, are a physiographic province of the larger Appalachian division and are also a belt within the Appalachian Mountains extending from southeastern New York through northwestern New...
of the eastern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
The Pocono is also a lateral equivalent of the Purslane Sandstone in Maryland and West Virginia. D. Brezinski of Maryland Geological Survey recommended abandoning use of the term Pocono in Maryland in favor of "Purslane" in 1989.
Description
The Pocono is a dominantly gray color with quartziticQuartzite
Quartzite is a hard metamorphic rock which was originally sandstone. Sandstone is converted into quartzite through heating and pressure usually related to tectonic compression within orogenic belts. Pure quartzite is usually white to gray, though quartzites often occur in various shades of pink...
medium to coarse-grained sandstones. The base of the Pocono Formation is marked by conglomerate
Conglomerate (geology)
A conglomerate is a rock consisting of individual clasts within a finer-grained matrix that have become cemented together. Conglomerates are sedimentary rocks consisting of rounded fragments and are thus differentiated from breccias, which consist of angular clasts...
.
Notable Exposures
- The type section of the Burgoon Sandstone is in the valley of Burgoon Run, above Kittanning Point, Blair County, PennsylvaniaBlair County, Pennsylvania-Significant Topographic Features:*Brush Mountain*Logan Valley*Morrison Cove*Tussey Mountain-Demographics:As of the census of 2000, there were 129,144 people, 51,518 households, and 34,877 families residing in the county. The population density was 246 people per square mile . There were 55,061...
. - A spectacular exposure of the Purslane Sandstone (equivalent to the Pocono) is at the I-68Interstate 68Interstate 68 is a Interstate highway in the U.S. states of West Virginia and Maryland, connecting in Morgantown to in Hancock. is also Corridor E of the Appalachian Development Highway System. From 1965 until the freeway's construction was completed in 1991, it was designated as...
road cut through Sideling HillSideling HillSideling Hill is a long, steep, narrow mountain ridge in the Ridge-and-Valley physiographic province of the Appalachian Mountains, located in Washington County in western Maryland and adjacent West Virginia and Pennsylvania, USA...
in Maryland.
Age
Relative age dating of the Pocono places it in the lower Mississippian period. The lower boundary is with the Spetchy Kopf Formation and Huntley Mountain FormationHuntley Mountain Formation
The Huntley Mountain Formation is a late Devonian and early Mississippian mapped bedrock unit in Pennsylvania, in the United States.-Description:The formation is composed of relatively soft grayish-red shale and olive-gray sandstone...
. In South-central Pennsylvania, the Pocono often interfingers with the Rockwell Formation
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:...
.