- Passaic Formation
The Passaic Formation is a mapped bedrock unit in
Pennsylvania ,New Jersey , andNew York . It was previously known as the Brunswick Formation since it was first described in the vicinity ofNew Brunswick, New Jersey . It is now named for thePassaic River inNew Jersey .Description
The Passaic is defined as a reddish-brown
shale ,siltstone andmudstone with a few green and brown shale interbeds; red and dark-gray interbeddedargillite s near the base. [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.] In New Jersey, there are conglomerate andsandstone beds within the formation.The Passaic is mostly
playa andalluvial fan deposits resulting from the rifting ofPangea . The red color is often evidence that the sediments were deposited in arid conditions.Faill, R.T., (2004). The Birdsboro Basin. "Pennsylvania Geology" V. 34 n. 4.] Interfingered with the Passaic, theLockatong Formation are lake sediments, which grew during wetter climatic cycles during the late Triassic..] These sediments came from the northwest and contain clasts from Appalachian formations.Fossils
Age
Relative age dating of the Passaic places it in the Late
Triassic period to the earlyJurassic , being deposited between 225 to 190 (±5) million years ago. It rests unconformably a top many different formations of the Appalachian Piedmont. It interfingers with the Lockatong Formation and also rests conformably atop theStockton Formation . There are numerousdiabase intrusions into the Passaic with local contact metamorphic rocks. [Berg, T.M., et al., (1983). Stratigraphic Correlation Chart of Pennsylvania: G75, Pennsylvania Geologic Survey, Harrisburg, Pennsylvania.]Economic Uses
References
ee also
*
Geology of Pennsylvania
*Geology of New Jersey
Wikimedia Foundation. 2010.