Kurupa Sandstone

Unit symbol: Mes
Age range Lower Mississippian (358.9 to 346.7 Ma)
Lithology: Sedimentary
Group name: Endicott Group, undivided
Sandstone, light- to medium-gray, in beds up to 1 m thick. Unit contains abundant amalgamated graded beds, abundant flutes and grooves, and well developed Bouma sequences. Sand-sized grains, in declining order of abundance, are quartz, chert, and feldspar. Weathers reddish brown, forms resistant ridges or spurs on valley walls. Well exposed at type locality in Kurupa Hills and in Akmalik Creek in the Killik River quadrangle. Contains abundant plant fossils, particularly near top of formation, and has scattered brachiopods near Otuk Creek in the western Killik River quadrangle. Thickness less than 40 m, grades downward into Hunt Fork Shale (unit Degh; Mull and others, 1994). Unit is primarily mapped in the central Brooks Range. Also included here on the basis of lithologic similarity are rocks mapped by Brosgé and others (1979) as the shale and sandstone member of the Kayak Shale in the Philip Smith Mountains quadrangle

Source map information

Source map Mull, C.G., Moore, T.E., Harris, E.E., and Tailleur, I.L., 1994, Geologic map of the Killik River quadrangle, Brooks Range, Alaska: U.S. Geological Survey Open-File Report 94-679, 1 sheet, scale 1:125,000.
Symbol Mku
Unit name Kurupa Sandstone; Picnic Creek Allochthon, Akmalik Creek Sequence
Description Sandstone, light- to medium-gray, beds up to 1 m thick, abundant amalgamated graded beds, abundant flutes and grooves and well developed Bouma sequences. Sand components in declining order of abundance: quartz, chert, feldspar. Weathers reddish brown, forms resistant ridges or spurs on valley walls. Well exposed at type locality in Kurupa Hills and in Akmalik Creek. Contains abundant plant fossils particularly near top formation, and scattered brachiopods near Otuk Creek. Kinderhookian to Meramecian. Thickness < 40 m, grades downward into Hunt Fork Shale.
Lithology Sedimentary

Correlated geologic units

Label Mks
Description Endicott Group, Kurupa Sandstone
Geologic age Mississippian
Geologic setting Sedimentary, slope-and-deep-water
Lithology Form Importance
Quartzose-sandstone < Sandstone < Clastic < Sedimentary Bed Major
Siltstone < Clastic < Sedimentary Carbonaceous Minor