Chickies Formation
Chickies Formation Stratigraphic range: Cambrian | |
---|---|
Type | Metamorphic |
Sub-units | Hellam Conglomerate Member |
Lithology | |
Primary | Quartzite |
Other | Slate, schist |
Location | |
Region | Pennsylvania, New Jersey, Maryland |
Country | United States |
Extent | Mid-Atlantic United States |
Type section | |
Named for | Chickies Rock |
Named by | J. Peter Lesley |
Year defined | 1876 |
The Cambrian Chickies Formation is a mapped bedrock unit in Pennsylvania, New Jersey, and Maryland. It is named for Chickies Rock, north of Columbia, Pennsylvania along the Susquehanna River.
Description[]
The Chickies Formation is described as a light-gray to white, hard, massive quartzite and quartz schist with thin interbedded dark slate at the top. Included at the base is the Hellam Conglomerate Member. It is a rare metamorphic rock that has fossils; Skolithos is found throughout the formation.[1]
Depositional age[]
Relative age dating places the Chickies in the Lower Cambrian Period, deposited between 542 and 520 million years ago (±2 million years).[2]
Economic geology[]
The Chickies is quarried as a building stone and for aggregate. The stone used to build the restrooms at Valley Forge National Historical Park is Chickies quartzite.[3]
See also[]
References[]
- ^ Berg, T.M., Edmunds, W.E., Geyer, A.R. and others, compilers, (1980). Geologic Map of Pennsylvania: Pennsylvania Geologic Survey, Map 1, scale 1:250,000.
- ^ Blackmer, G.C., (2005). Preliminary Bedrock Geologic Map of a Portion of the Wilmington 30- by 60-Minute Quadrangle, Southeastern Pennsylvania. Pennsylvania Geologic Survey, Open-File Report OFBM-05-01.0.
- ^ http://www.dcnr.state.pa.us/topogeo/ParkGuides/pg08.pdf[bare URL PDF]
- Geologic formations of New Jersey
- Cambrian System of North America
- Cambrian Maryland
- Cambrian geology of Pennsylvania
- Quartzite formations