Geologic Map of Alaska: Pelitic and quartzose schist of the Alaska Range

Pelitic and quartzose schist of the Alaska Range

Unit symbol:	Pzarqm
Age range	Devonian or older (541 to 358.9 Ma)
Lithology:	Metamorphic
Group name:	Schist and phyllite of the Alaska Range

Dominantly pelitic and quartz-rich schist and quartzite in the Mount Hayes (Nokleberg and others, 1992a), Healy (Csejtey and others, 1992), and Mount McKinley (Bela Csejtey, Jr., written commun., 1993) quadrangles; includes subordinate calc-schist and feldspathic schist. Generally underwent greenschist to amphibolite facies metamorphism, with or without greenschist facies retrogression. Unit is lithologically similar to units PzPxyqs and PzPxyqm in the Yukon-Tanana Upland; all three units contain metaigneous rocks that yield Devonian zircon ages

Source map information

Source map	Reed, B.L., and Nelson, S.W., 1980, Geologic map of the Talkeetna quadrangle, Alaska: U.S. Geological Survey, Miscellaneous Investigation Series Map I-1174, 15 pages, 1 plate, scale 1:250,000.
Symbol	Pzsv
Unit name	Quartzite, semischist, and metavolcanic rocks
Description	Tan to light-greenish-gray, low-grade (greenschist facies), regionally metamorphosed quartzite, quartz semischist, quartz grit, metavolcanic rocks, and minor conglomerate, limestone, phyllite, and quartz-muscovite schist. Isoclinally folded.
Lithology	Metamorphic

Correlated geologic units

Label	PzZaqs
Description	Pelitic and quartzose schist of the Alaska Range
Geologic age	Paleozoic to Devonian
Geologic setting	Sedimentary, undivided

Lithology	Form	Importance
Pelitic-schist < Metaclastic < Metasedimentary < Metamorphic	Greenschist	Major
Quartzite < Metaclastic < Metasedimentary < Metamorphic	Greenschist	Major
Phyllite < Metaclastic < Metasedimentary < Metamorphic	Greenschist	Minor