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Chickies Formation
Mapped bedrock unit in the United States From Wikipedia, the free encyclopedia
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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.
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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]
- Specimen of Chickies Banded Slate. Shows older folded schistosity parallel to bedding cut by younger cleavage inclined to bedding.
- Specimen of mica schist from upper beds of Chickies Quartzite. Shows stretched epigenetic tourmaline.
- Cobble bed in Hellam Conglomerate Member
See also
References
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