Geologic Map of Alaska: Unconsolidated surficial deposits, undivided

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	Richter, D.H., Preller, C.C., Labay, K.A., and Shew, N.B., 2005, Geology of Wrangell-Saint Elias National Park and Preserve, southcentral Alaska: U.S. Geological Survey Scientific Investigations Series Map SIM-2877, 15 p., 1 sheet, scale 1:350,000.
Symbol	Qc
Unit name	Colluvium, undifferentiated
Description	Chiefly talus but includes deposits of small landslides, rock glaciers, and other mass-wasting processes. Generally includes a large proportion of alluvium in small fans and cones and reworked glacial deposits. Sand, gravel, boulders, diamicton, and rubble
Lithology	Unconsolidated

Correlated geologic units

Label	Qc
Description	Colluvium
Geologic age	Pleistocene to Holocene
Geologic setting	Unconsolidated

Lithology	Form	Importance
Gravel < Coarse-detrital < Unconsolidated	Colluvial	Major
Silt < Fine-detrital < Unconsolidated	Colluvial	Major
Sand < Coarse-detrital < Unconsolidated	Colluvial	Indeterminate, major
Boulders < Coarse-detrital < Unconsolidated	Colluvial	Incidental