The Pennsylvanian is, on the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly 323.2 million years ago to 298.9 million years ago. As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain by a few hundred thousand years. The Pennsylvanian is named after the U.S. state of Pennsylvania, where the coal-producing beds of this age are widespread.
The geology of Tennessee is as diverse as its landscapes. Politically, Tennessee is broken up into three Grand Divisions: East, Middle, and West Tennessee. Physically, Tennessee is also separated into three main types of landforms: river valley plain, highlands and basins, and mountains.
The San Juan Basin is a geologic structural basin located near the Four Corners region of the Southwestern United States. The basin covers 7,500 square miles and resides in northwestern New Mexico, southwestern Colorado, and parts of Utah and Arizona. Specifically, the basin occupies space in the San Juan, Rio Arriba, Sandoval, and McKinley counties in New Mexico, and La Plata and Archuleta counties in Colorado. The basin extends roughly 100 miles (160 km) N-S and 90 miles (140 km) E-W.
The Silurian Bloomsburg Formation is a mapped bedrock unit in Pennsylvania, New Jersey, New York and Maryland. It is named for the town of Bloomsburg, Pennsylvania, in which it was first described. The Bloomsburg marked the first occurrence of red sedimentary rocks in the Appalachian Basin.
The Silurian Tuscarora Formation — also known as Tuscarora Sandstone or Tuscarora Quartzite — is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia, US.
The Ordovician Juniata Formation is a mapped bedrock unit in Pennsylvania, West Virginia, Virginia, Tennessee, and Maryland. It is a relative slope-former occurring between the two prominent ridge-forming sandstone units: the Tuscarora Formation and the Bald Eagle Formation in the Appalachian Mountains.
The Hamilton Group is a Devonian-age geological group which is located in the Appalachian region of the United States. It is present in New York, Pennsylvania, Maryland, Ohio, West Virginia, northwestern Virginia and Ontario, Canada, and is mainly composed of marine shale with some sandstone.
The Devonian Mahantango Formation is a mapped bedrock unit in Pennsylvania, West Virginia, and Maryland. It is named for the North branch of the Mahantango Creek in Perry and Juniata counties in Pennsylvania. It is a member of the Hamilton Group, along with the underlying the Marcellus Formation Shale. South of Tuscarora Mountain in south central Pennsylvania, the lower members of this unit were also mapped as the Montebello Formation. Details of the type section 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.
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 the formation crops out.
The Casselman Formation mapped sedimentary bedrock unit in Pennsylvania, Maryland, and West Virginia, of Pennsylvanian age. It is the uppermost of two formations in the Conemaugh Group, the lower being the Glenshaw Formation. The boundary between these two units is the top of the marine Ames Limestone. The Conemaugh Group overlies the Upper Freeport coal bed of the Allegheny Formation and underlies the Pittsburgh coal seam of the Monongahela Group.
The Glenshaw Formation is a mapped sedimentary bedrock unit in Pennsylvania, Maryland, West Virginia, and Ohio, of Pennsylvanian age. It is the lower of two formations in the Conemaugh Group, the upper being the Casselman Formation. The boundary between these two units is the top of the marine Ames Limestone. The Conemaugh Group overlies the Upper Freeport coal bed of the Allegheny Formation and underlies the Pittsburgh coal seam of the Monongahela Group.
The Bluefield Formation is a geologic formation in West Virginia. It preserves fossils dating back to the Mississippian subperiod of the Carboniferous period. Sediments of this age formed along a large marine basin lying in the region of what is now the Appalachian Plateau. The Bluefield Formation is the lowest section of the primarily siliciclastic Mauch Chunk Group, underlying the Stony Gap Sandstone Member of the Hinton Formation and overlying the limestone-rich Greenbrier Group.
The Council Grove Group is a geologic group in Kansas, Oklahoma, and Nebraska as well as subsurface Colorado. It preserves fossils dating to the Carboniferous-Permian boundary. This group forms the foundations and lower ranges of the Flint Hills of Kansas, underlying the Chase Group that forms the highest ridges of the Flint Hills.
The Sangre de Cristo Formation is a geologic formation in Colorado and New Mexico. It preserves fossils dating back to the late Pennsylvanian to early Permian.
The Sandia Formation is a geologic formation in New Mexico, United States. Its fossil assemblage is characteristic of the early Pennsylvanian.
The geology of Ohio formed beginning more than one billion years ago in the Proterozoic eon of the Precambrian. The igneous and metamorphic crystalline basement rock is poorly understood except through deep boreholes and does not outcrop at the surface. The basement rock is divided between the Grenville Province and Superior Province. When the Grenville Province crust collided with Proto-North America, it launched the Grenville orogeny, a major mountain building event. The Grenville mountains eroded, filling in rift basins and Ohio was flooded and periodically exposed as dry land throughout the Paleozoic. In addition to marine carbonates such as limestone and dolomite, large deposits of shale and sandstone formed as subsequent mountain building events such as the Taconic orogeny and Acadian orogeny led to additional sediment deposition. Ohio transitioned to dryland conditions in the Pennsylvanian, forming large coal swamps and the region has been dryland ever since. Until the Pleistocene glaciations erased these features, the landscape was cut with deep stream valleys, which scoured away hundreds of meters of rock leaving little trace of geologic history in the Mesozoic and Cenozoic.
The geology of Uzbekistan consists of two microcontinents and the remnants of oceanic crust, which fused together into a tectonically complex but resource rich land mass during the Paleozoic, before becoming draped in thick, primarily marine sedimentary units.
The Gobbler Formation is a geologic formation in the Sacramento Mountains of New Mexico. It preserves fossils dating back to the Moscovian Age of the Pennsylvanian Period.
Helen Morningstar was a geologist and paleontologist from Columbus, Ohio. She was born on September 23, 1891, and was an instructor for Ohio State University from 1917 to 1922. She died on July 31, 1951, at the age of 59 due to health complications.
The Carbondale Group is a Middle Pennsylvanian aged unit found in the Illinois Basin. This geologic unit is made up of siliciclastic rock and Coal beds.
