Lock Haven Formation
Encyclopedia
The Lock Haven Formation is a Devonian
mapped bedrock unit in Pennsylvania
, in the Appalachian Mountains
of the United States
.
, siltstone
, and shale
and is over 400 million years old. It is located in northcentral Pennsylvania.
and underlying Scherr Formation
. The Brallier Formation
usually underlies the Lock Haven.
The Minnehaha Springs Member (originally proposed as a member of the Scherr Formation
) is a "clastic bundle" consisting of interbedded medium gray siltstone and olive gray shale with some grayish-red siltstone and shale and some sandstone. It is interpreted as turbidite
s. This member is proposed to define the base of the Lock Haven Formation.
Devonian
The Devonian is a geologic period and system of the Paleozoic Era spanning from the end of the Silurian Period, about 416.0 ± 2.8 Mya , to the beginning of the Carboniferous Period, about 359.2 ± 2.5 Mya...
mapped bedrock unit in Pennsylvania
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...
, in the Appalachian Mountains
Appalachian Mountains
The Appalachian Mountains #Whether the stressed vowel is or ,#Whether the "ch" is pronounced as a fricative or an affricate , and#Whether the final vowel is the monophthong or the diphthong .), often called the Appalachians, are a system of mountains in eastern North America. The Appalachians...
of the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Description
The Lock Haven is gray to green-brown sandstoneSandstone
Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...
, siltstone
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
, and shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
and is over 400 million years old. It is located in northcentral Pennsylvania.
Stratigraphy
The Lock Haven may underlie various members of the Catskill Formation, although it may be a lateral equivalent of the Sherman Creek or Irish Valley Members of the Catskill. It is also a lateral equivalent of the Foreknobs FormationForeknobs Formation
The Devonian Foreknobs Formation is a mapped bedrock unit in Pennsylvania, Maryland, Virginia, and West Virginia.-Description:The Foreknobs Formation contains massive sandstones; siltstone; "redbeds" of brownish-gray sandstone, siltstone, and shale containing scattered marine fossils; and...
and underlying Scherr Formation
Scherr Formation
The Devonian Scherr Formation is a mapped bedrock unit in Pennsylvania, Maryland, Virginia and West Virginia.-Description:The Scherr Formation consists predominantly of siltstone and shale. Lower part of unit includes considerable fine-grained sandstone, while upper two thirds contains almost no...
. The Brallier Formation
Brallier Formation
The Devonian Brallier Formation is a mapped bedrock unit in Pennsylvania, Maryland, West Virginia, and Virginia.-Description:The 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...
usually underlies the Lock Haven.
The Minnehaha Springs Member (originally proposed as a member of the Scherr Formation
Scherr Formation
The Devonian Scherr Formation is a mapped bedrock unit in Pennsylvania, Maryland, Virginia and West Virginia.-Description:The Scherr Formation consists predominantly of siltstone and shale. Lower part of unit includes considerable fine-grained sandstone, while upper two thirds contains almost no...
) is a "clastic bundle" consisting of interbedded medium gray siltstone and olive gray shale with some grayish-red siltstone and shale and some sandstone. It is interpreted as turbidite
Turbidite
Turbidite geological formations have their origins in turbidity current deposits, which are deposits from a form of underwater avalanche that are responsible for distributing vast amounts of clastic sediment into the deep ocean.-The ideal turbidite sequence:...
s. This member is proposed to define the base of the Lock Haven Formation.
Notable Exposures
- Pine Creek GorgePine Creek GorgePine Creek Gorge, also known as, The Grand Canyon of Pennsylvania, is situated in approximately 160,000 acres of the Tioga State Forest in the U.S. State of Pennsylvania along Pine Creek. The Canyon begins south of Ansonia, near Wellsboro, along U.S. Route 6 and continues for approximately...
- Leberfinger Quarry, near Forksville in Sullivan CountySullivan County, PennsylvaniaSullivan County is a county located in the U.S. state of Pennsylvania. As of 2010, the population is 6,428. Sullivan County was created on March 15, 1847, from part of Lycoming County and named for Charles Sullivan, leader of the Pennsylvania Senate...
, Pennsylvania. Brachiopods, CruzianaCruzianaCruziana is a trace fossil consisting of elongate, bilobed, approximately bilaterally symmetrical burrows, usually preserved along bedding planes, with a sculpture of repeated striations that are mostly oblique to the long dimension...
and other trace fossilIchnologyIchnology is the branch of geology that deals with traces of organismal behavior, such as burrows and footprints. It is generally considered as a branch of paleontology; however, only one division of ichnology, paleoichnology, deals with trace fossils, while neoichnology is the study of modern traces...
s, and carbonized plant fossils are present.