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 Bundtzen, T.K., and Jorgenson, Torre, 2005, Lime Hills and western Tyonek quadrangles surficial geologic mapping and ecosystem development analysis of glacial deposits: U.S. National Park Service Contract #D9855040060 to: ABR, Inc., P.O. Box 80410, Fairbanks, Alaska 99708, 85 p., 35 plates, scale 1:63,360.
Symbol Qmw-4 or Qgt-6
Unit name Till of Middle Farewell II Glaciation
Description Unsorted to poorly sorted, clay, silt, sand, gravel and diamicton deposited by glacial ice. Abundant erratics are polyhedral, striated, and subrounded, relatively fresh granitic boulders up to 6.5 feet (2.0 m) in diameter derived from 1) the Revelation Batholith; 2) Tired Pup, two-mica Pluton (southern edge of Revelation Mountains, and 3) hornblende rich tonalite which are collectively granitic types making up the core of the Alaska Aleutian Range Batholith. Prominent moraines are not dissected by small second and third order streams, but cut by the Swift, Stony, and Big Rivers. Irregular craggy Moraines contain from 7-15 kettles per km2. In Big River, the terminal ice position is marked by a prominent granitic boulder field in a restricted 4-mile-long canyon, about 8 miles (12 km) below the confluence of Lyman Fork and Big River. Distinctive lateral moraines ranging from 1,600 to 2,400 feet (490670 m) in elevation mark Qmw-4 moraines in the valleys of Stony, Swift, and Big Rivers as they break out onto the piedmont west of the mountain front. A large pro-glacial lake deposit (Qgl), is damned up behind Qmw-4 moraines in the valley of Stony River; the 1214 mile long (19-22 km), ancestral lake is centered on the mouth of the Telequana River where it enters Stoney River. Bundtzen and others (1994) show Qmw-4 deposits in Lime Hills C-5 quadrangle as Qgt-2 deposits of Late Wisconsin age. Qmw-4 deposits are probably equivalent to either the Newhalen or Iliuk stades of the Brooks Lake Glaciation as defined by Detterman (1986). Qmw-4 is also equivalent to the terminal ice position that damned up glacial Lake Telequana in Lake Clark Quadrangle (unit Qw3 of Wilson, 2004, unpublished)
Lithology Unconsolidated

Correlated geologic units

Label Qw2
Description Late Wisconsin, Newhalen and other till
Geologic age Late-Pleistocene
Geologic setting Unconsolidated
Lithology Form Importance
Gravel < Coarse-detrital < Unconsolidated Glacial Major
Boulders < Coarse-detrital < Unconsolidated Glacial Indeterminate, major
Sand < Coarse-detrital < Unconsolidated Glacial Indeterminate, major
Silt < Fine-detrital < Unconsolidated Glacial Indeterminate, major