Chickies Formation
The Cambrian Chickies Formation is a mapped bedrock unit in Pennsylvania 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 to 520 million years ago (±2 million years).[2]
Economic uses
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
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