The Lock Haven Formation is a

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 ...

mapped bedrock unit in Pennsylvania, in the Appalachian Mountains of the United States.

Description

The Lock Haven is gray to green-brown sandstone,

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

, and

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

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 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 sha ...

and underlying

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 san ...

. The Brallier Formation usually underlies the Lock Haven. The Minnehaha Springs Member (originally proposed as a member of the

) is a "

clastic Clastic rocks are composed of fragments, or clasts, of pre-existing minerals and rock. A clast is a fragment of geological detritus,Essentials of Geology, 3rd Ed, Stephen Marshak, p. G-3 chunks, and smaller grains of rock broken off other rocks ...

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

Notable Exposures

* Pine Creek Gorge * Leberfinger Quarry, near Forksville in Sullivan County, Pennsylvania. Fossils at this location include Brachiopods and carbonized plant fossils, while trace fossils include '' Cruziana'', '' Arenicolites'', and ''

Rhizocorallium ''Rhizocorallium'' is an ichnogenus of burrow, the inclination of which is typically within 10° of the bedding planes of the sediment. These burrows can be very large, over a meter long in sediments that show good preservation, e.g. Jurassic roc ...

''.

Description

Stratigraphy

Notable Exposures

References

See also