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 Patton, W.W., Jr., Wilson, F.H., and Labay, K.A., in press, Reconnaissance geologic map of the lower Yukon River Region, Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-3015, scale 1:500,000.
Symbol Qac
Unit name Alluvial, colluvial, and glacial drift deposits, undivided
Description Alluvial and colluvial deposits consist mainly of silt, sandy silt, and peat. Alluvium is chiefly fluvial in origin, but locally includes reworked windblown deposits. Glaical drift composed of sand, gravel, and boulder morainal and outwash deposits
Lithology Unconsolidated

Correlated geologic units

Label Qs
Description Surficial deposits, undifferentiated
Geologic age Pleistocene to Holocene
Geologic setting Unconsolidated
Lithology Form Importance
Gravel < Coarse-detrital < Unconsolidated Bed Indeterminate, major
Sand < Coarse-detrital < Unconsolidated Bed Indeterminate, major
Clay < Fine-detrital < Unconsolidated Bed Indeterminate, major
Silt < Fine-detrital < Unconsolidated Bed Indeterminate, major
Peat < Unconsolidated Bed Indeterminate, major