Mafic igneous-clast conglomerate, sandstone, and mudstone

Unit symbol: Kipc
Age range Lower Cretaceous (113 to 100.5 Ma)
Lithology: Sedimentary
Group name: Mafic igneous-clast conglomerate, sandstone, and mudstone
Massive, poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix in west-central Alaska (Patton and others, 2009). Clasts are predominately mafic intrusive and extrusive rocks, varicolored chert, and locally, metagraywacke. Limestone, quartz, and granitic rock clasts present in subordinate amounts. Conglomerate is interbedded with mafic- and calcareous-clast graywacke and mudstone. Unit composed chiefly of debris thought to be eroded from the Angayucham-Tozitna terrane (Patton and others, 2009). Unit stratigraphically underlies unit Kqc. Contains marine mollusks of Early Cretaceous(?) age in the Selawik quadrangle

Source map information

Source map Patton, W.W., Jr., Wilson, F.H., Labay, K.A., and Shew, Nora, 2009, Geologic map of the Yukon-Koyukuk basin, Alaska: U.S. Geological Survey Scientific Investigations Map SIM-2909, 26 p., 2 sheets, scale 1:500,000.
Symbol Kmc
Unit name Mafic igneous-clast conglomerate, sandstone, and mudstone
Description Consists of massive poorly stratified and poorly sorted conglomerate composed of pebble- to cobble-size clasts in a graywacke and mudstone matrix. Clasts predominately mafic intrusive and extrusive rocks, varied colored chert, and locally metagraywacke. Limestone, quartz, and granitic rock clasts present in subordinate amounts. Conglomerate is interbedded with mafic- and calcareous-clast graywacke and mudstone. Unit composed chiefly of debris eroded from the Angayucham-Tozitna terrane. Unit stratigraphically underlies unit Kqc. Occurs at scattered localities along the northern and southeastern margin of the Yukon-Koyukuk Basin from Baird Mountains and Selawik quadrangles eastward to Wiseman and Bettles quadrangles and then southwestward to Ruby quadrangle
Lithology Sedimentary

Correlated geologic units

Label Kipc
Description Igneous pebble-cobble conglomerate, Albian and Late Cretaceous?
Geologic age Albian
Geologic setting Sedimentary, shallow-marine-siliciclastic
Lithology Form Importance
Conglomerate < Clastic < Sedimentary Bed Major