Lock Haven Formation

The Lock Haven Formation is a Devonian mapped bedrock unit in Pennsylvania, in the Appalachian Mountains of the United States.

Lock Haven Formation
Stratigraphic range: Devonian
Brachiopod casts in the Lock Haven, Leberfinger Quarry, Sullivan County, PA
Type	sedimentary
Unit of	Susquehanna Group
Sub-units	lower shaly member, upper sandy member, Minnehaha Springs Member
Underlies	Catskill Formation
Overlies	Brallier Formation
Lithology
Primary	siltstone, shale, sandstone
Other	conglomerate
Location
Region	Appalachian Mountains
Country	United States
Extent	Pennsylvania
Type section
Named for	Lock Haven, Pennsylvania
Named by	Faill and Wells, 1977[1]

Description

The Lock Haven is gray to green-brown sandstone, siltstone, and shale and is over 400 million years old. It is located in northcentral Pennsylvania.^[2][3]

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 and underlying Scherr Formation. The Brallier Formation usually underlies the Lock Haven.^[4]

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 turbidites.^[5] This member is proposed to define the base of the Lock Haven Formation.^[6]

Notable Exposures

• Pine Creek Gorge^[7]
• 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.^[8]

See also

• Devonian portal

• Geology of Pennsylvania