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 Nelson, S.W., Dumoulin, J.A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645B, pamphlet, 16 p., 1 sheet, scale 1:250,000 (Chugach NF Arc/Info coverage 1993).
Symbol Qu
Unit name Surficial deposits, undivided
Description Predominantly alluvium deposited by nonglacial streams and outwash deposited by glacial meltwater. Consists of sand and gravel; terminal, lateral, and ground moraine composed of unsorted deposits of boulders, cobbles, gravel, and sand left by the retreat of alpine, valley, and regional glaciers; and talus and landslide deposits from adjacent bedrock. Also includes less extensive deposits consisting mostly of sand that may be locally abundant and form such features as beaches, spits, offshore bars in coastal areas, and dunes on the Copper River delta. Surficial deposits, undivided
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