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 Smith, T.E., Robinson, M.S., Weber, F.R., Waythomas, C.W., and Reifenstuhl, R.R., 1994, Geologic map of the Upper Chena River area, eastern interior Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 115, 1 sheet, scale 1:63,360, pamphlet, 19 p.
Symbol pCcm
Unit name Marble
Description Interbedded with pCcq. Forms beds of gray, white, or pale-green marble to 20 feet thick. Variations include gray weathering, banded, coarse-grained marble; brown and white, laminated, sugary-textured nonschistose marble; and fine-grained, greenish-gray, impure marble containing feldspar, quartz, and diopside to 20 percent. Limonitic clots are common in marble. Presence of diopside indicates metamorphism in amphibolite facies
Lithology Metamorphic

Correlated geologic units

Label Pzydm
Description Dolomite and marble, Yukon-Tanana
Geologic age Neoproterozoic to Devonian
Geologic setting Sedimentary, carbonate
Lithology Form Importance
Marble < Metacarbonate < Metasedimentary < Metamorphic Greenschist Major
Dolostone < Carbonate < Sedimentary Bed Major