The Peach Bottom area in the Pennsylvania - Maryland Piedmont

by Faill, R.T., and Smith, R.C.

in Fleeger, G.M., and Whitmeyer, S.J., eds.,

The Mid-Atlantic Shore to the Appalachian Highlands:
Field Trip Guidebook for the 2010 Joint Meeting of the
Northeastern and Southeastern GSA Sections,
Geological Society of America Field Guide 16, (2010)

Abstract

The Appalachian Piedmont in south-central Pennsylvania and north-central Maryland contains metasedimentary siliciclastic rocks (phyllites to quartzites) that were deposited largely offshore of Laurentia, prior to and during the early history of the Iapetan ocean. The Peach Bottom area is centered on the belt of Peach Bottom Slate and overlying Cardiff Quartzite, which is surrounded by the late Neoproterozoic and early Paleozoic rocks of the Peters Creek and Scott Creek (new name) Formations. Their provenance was the Brandwine and Baltimore microcontinents that lay further offshore of the Laurentian coast. This area also includes an ophiolitic melange that formed in front of an advancing island arc in Iapetus. All these rocks lay largely undisturbed throughout much of the Paleozoic, experiencing only chloritegrade greenschist facies metabolism thorugh deep burial. Alleghanian thrusting associated with the growth of the Tucquan anticline imparted their present widespread, monocline, steep southeast dip of the bed-parallel foliation.

[The first stop on this trip is at a Sykesville Formation exposure on Goat Hill Road near New Texas - MB]

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