Intricately intruded areas of volcanic graywacke and mudstone

Unit symbol: TKis
Age range Tertiary or Upper Cretaceous (113 to 61.6 Ma)
Lithology: Sedimentary
Group name: Nonmarine to shelf sedimentary rocks
Unit is mapped in areas where numerous small hypabyssal bodies of rhyolite and dacite intrude the Ksd unit. Igneous complexes are composed of small, closely-spaced rhyolite, dacite, andesite, granite, granodiorite, tonalite, and monzonite porphyry bodies. Intrusive bodies are too small and too numerous to be mapped separately. Sedimentary host rocks are altered to erosion-resistant hornfels. A felsic hypabyssal body belonging to the complex in the southwestern part of Unalakleet quadrangle yielded a single K/Ar isotopic cooling age of 68.8±3 Ma (Patton and Moll-Stalcup, 1996)

Source map information

Source map Patton, W.W., Jr., and Moll-Stalcup, E.J., 2000, Geologic map of the Nulato quadrangle, west-central Alaska: U.S. Geological Survey Geologic Investigations Series I-2677, 41 p., 1 sheet, scale 1:250,000.
Symbol TKis
Unit name Shallow intrusive rocks of silicic and intermediate composition, marine and nonmarine sandstone, shale, and conglomerate, and volcaniclastic graywacke and mudstone turbidite deposits and thermally altered sedimentary rocks
Description Shallow intrusive rocks of silicic and intermediate composition, marine and nonmarine sandstone, shale, and conglomerate, and volcaniclastic graywacke and mudstone turbidite deposits and thermally altered sedimentary rocks
Lithology Igneous

Correlated geologic units

Label Ksi
Description Rhyolite and dacite, and sandstone, shale, and conglomerate deltaic deposits and intricately intruded areas of volcanic graywacke and mudstone, late Early Cretaceous (Albian)
Geologic age Albian to Danian
Geologic setting Sedimentary, deltaic-and-nearshore
Lithology Form Importance
Hypabyssal-dacite < Felsic-hypabyssal < Hypabyssal < Igneous Dike or sill Major
Hypabyssal-rhyolite < Felsic-hypabyssal < Hypabyssal < Igneous Dike or sill Major