Quartzite and pelitic schist

Unit symbol: PzPxyqs
Age range Devonian and older (635 to 358.9 Ma)
Lithology: Metamorphic
Group name: Pelitic schist and quartzite and mafic interbeds (Yukon-Tanana crystalline complex)
Dominantly quartzite, schistose quartzite, and quartz-mica schist; also contains subordinate gritty quartzite, chlorite schist, calc-silicate schist, marble, magnetite-biotite schist, amphibolite, and greenstone. Ranges from amphibolite to upper greenschist facies and locally retrograded to lower greenschist facies (Nokleberg and others, 1992a; Smith and others, 1994). Corresponds, in part, to the Fairbanks schist of Newberry and others (1996) of the Fairbanks mining district and surrounding areas of the southeastern Livengood and northeastern Fairbanks quadrangles (Robinson and others, 1990; Weber and others, 1992; Newberry and others, 1996) as well as a large portion of the Circle quadrangle (Foster and others, 1983). Smaller areas of exposure occur in the southern Big Delta quadrangle (Weber and others, 1978) and in the Eagle quadrangle (Foster, 1976). In the Circle quadrangle and northern Big Delta quadrangle, small exposures of gray or greenish-gray marble and gray to cream-colored dolomitic marble are included in this unit; diopside is present locally, indicating amphibolite facies metamorphism. No age control exists for these carbonate rocks

Source map information

Source map Foster, H.L., Laird, Jo, Keith, T.E.C., Cushing, G.W., and Menzie, D.W., 1983, Preliminary geologic map of the Circle quadrangle, Alaska: U.S. Geological Survey Open-File Report, 83-170-A, scale 1:250,000.
Symbol PzpCq
Unit name Quartzite and quartzitic schists
Description Gray or greenish-gray quartzite and quartzitic schists are dominant rock types. Minor pelitic schist, calc-silicate, mafic schist, and rare marble are interlayered with quartzite and quartzitic schists.
Lithology Metamorphic

Correlated geologic units

Label PzZyqs
Description Greenschist facies muscovite chlorite schist, quartzite and phyllite [Fairbanks schist unit - undivided]
Geologic age Paleozoic to Devonian
Geologic setting Sedimentary, shallow-marine-siliciclastic
Lithology Form Importance
Quartzite < Metaclastic < Metasedimentary < Metamorphic Greenschist Major
Quartz-feldspar-schist < Schist < Metamorphic Greenschist Major
Amphibole-schist < Schist < Metamorphic Greenschist Minor
Calc-silicate-schist < Schist < Metamorphic Greenschist Minor
Marble < Metacarbonate < Metasedimentary < Metamorphic Greenschist Incidental