The Lock Haven Formation is a Devonian mapped bedrock unit in

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, ...

, in the

Appalachian Mountains The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...

of the

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Description

The Lock Haven is gray to green-brown

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

, siltstone, and shale 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 The Devonian Catskill Formation or the Catskill Clastic wedge is a unit of mostly terrestrial sedimentary rock found in Pennsylvania and New York. Minor marine layers exist in this thick rock unit (up to ). It is equivalent to the Hampshire Form ...

, 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 Formation and underlying Scherr Formation. The

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 s ...

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 A turbidite is the geologic deposit of a turbidity current, which is a type of amalgamation of fluidal and sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Sequencing Turbidites wer ...

s. This member is proposed to define the base of the Lock Haven Formation.

Notable Exposures

Pine Creek Gorge Pine Creek Gorge, sometimes called The Grand Canyon of Pennsylvania, is a gorge carved into the Allegheny Plateau by Pine Creek in north-central Pennsylvania. It sits in about of the Tioga State Forest. The canyon begins south of Ansonia, nea ...

* Leberfinger Quarry, near Forksville in Sullivan County, Pennsylvania. Fossils at this location include

Brachiopods Brachiopods (), phylum Brachiopoda, are a phylum of trochozoan animals that have hard "valves" (shells) on the upper and lower surfaces, unlike the left and right arrangement in bivalve molluscs. Brachiopod valves are hinged at the rear end, wh ...

and carbonized plant fossils, while

trace fossils A trace fossil, also known as an ichnofossil (; from el, ἴχνος ''ikhnos'' "trace, track"), is a fossil record of biological activity but not the preserved remains of the plant or animal itself. Trace fossils contrast with body fossils ...

include ''

Cruziana ''Cruziana'' 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. It is fo ...

'', '' Arenicolites'', and '' Rhizocorallium''.

Description

Stratigraphy

Notable Exposures

References

See also