Unconsolidated surficial deposits, undivided

Unit symbol: Qs
Age range Quaternary (1.806 to 0 Ma)
Lithology: Unconsolidated
Group name: Unconsolidated and poorly consolidated surficial deposits
Unconsolidated, poorly to well-sorted, poorly to moderately well-stratified deposits; consist predominantly of alluvial, colluvial, marine, lacustrine, eolian, and swamp deposits. May include some glacial deposits. Also includes widespread glacial and periglacial deposits that consist of end, lateral, and ground moraine, outwash, rock glacier deposits, and other glacial and periglacial deposits as well as glacially scoured bedrock that may be covered with thin, glacially derived deposits. These glacial deposits are of Holocene and Pleistocene age and may include small areas of potentially latest Tertiary deposits. Map unit locally includes reworked volcanic debris as well as block and ash flows. On generalized map, shown as part of unit QTs

Source map information

Source map Mull, C.G., Harris, E.E., Reifenstuhl, R.R., and Moore, T.E., 2000, Geologic map of the Coke Basin-Kukpowruk River area, De Long Mountains D-2 and D-3 quadrangles, Alaska: Alaska Division of Geological & Geophysical Surveys Report of Investigation 2000-2, 1 sheet, scale 1:63,360. doi:10.14509/2737.
Symbol Qa
Description Silt, sand, and gravel deposited in active, typically meandering stream and river channels; including intermittent tributaries active during seasonal runoff and flood events. Unit includes abandoned channels and floodplain deposits which may be mantled by fluvial silt overbank deposits with little or no vegetation. Unit may also include low terraces above the active floodplain that locally support dwarf willows adjacent to the rivers.
Lithology Unconsolidated

Correlated geologic units

Label Qa
Description Alluvium
Geologic age Pleistocene to Holocene
Geologic setting Unconsolidated
Lithology Form Importance
Gravel < Coarse-detrital < Unconsolidated Bed Major
Sand < Coarse-detrital < Unconsolidated Bed Major
Coarse-detrital < Unconsolidated Bed Indeterminate, major
Silt < Fine-detrital < Unconsolidated Bed Indeterminate, major
Peat < Unconsolidated Bed Indeterminate, major