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., 1976, Geologic map of the Eagle quadrangle, Alaska: U.S. Geological Survey, Miscellaneous Investigations I-922, 1 sheet, scale 1:250,000.
Symbol Pzb
Unit name Biotite schist, quartzite, and marble
Description Also includes muscovite schist, quartz-epidote schist, quartz-graphite schist, quartz-amphibolite schist and some greenschist with interlayered greenstone. Locally includes quartz-biotite gneiss, retrograded gneiss, amphibolite, and hornfelsic gneiss and schist. Biotite abundant and garnet locally abundant. Probably mostly epidote-amphibolite facies but may include rocks of greenschist and amphibolite facies. Probably mostly Paleozoic age with metamorphism in Paleozoic or Mesozoic time
Lithology Metamorphic

Correlated geologic units

Label PzZyqs
Description Quartzitic and pelitic schist of the Yukon-Tanana crystalline complex
Geologic age Paleozoic to Devonian
Geologic setting Sedimentary, shallow-marine-siliciclastic
Lithology Form Importance
Quartzite < Metaclastic < Metasedimentary < Metamorphic Amphibolite, epidote-amphibolite Major
Mica-schist < Schist < Metamorphic Amphibolite, epidote-amphibolite Major
Amphibolite < Metamorphic Amphibolite, epidote-amphibolite Minor
Biotite-gneiss < Gneiss < Metamorphic Amphibolite, epidote-amphibolite Minor