Adams Argillite

Unit symbol: Ca
Age range Cambrian (541 to 485.4 Ma)
Lithology: Sedimentary
Group name: Adams Argillite
Light-gray argillite, siltstone, and cross-laminated quartzite with an oolitic and sandy limestone near base of unit (Brabb and Churkin, 1969). Age control derives from worm(?) burrows in the quartzite, Oldhamia in the argillite, and, in the limestone near the base of the unit, archaeocyathids and trilobites of Early Cambrian age (Brabb and Churkin, 1969). Unit thickness is 90 to 180 m. In Eagle quadrangle, correlative units (included in this map unit) include greenish-gray laminated quartzite that has interbeds of greenish-gray and dark-gray argillite and minor grayish-red argillite, siliceous shale, chert, and dark-gray sandy limestone (Foster, 1976). Unit includes type area of the Adams Argillite in the Charley River quadrangle of east-central Alaska (Brabb and Churkin, 1969) as well as rocks that are apparently correlative in the Demarcation Point quadrangle of northeast Alaska (Reiser and others, 1980)

Source map information


Correlated geologic units

Label Ca
Description Adams Argillite
Geologic age Cambrian
Geologic setting Sedimentary, slope-and-deep-water
Lithology Form Importance
Argillite < Metaclastic < Metasedimentary < Metamorphic Major
Siltstone < Clastic < Sedimentary Bed Major
Quartzite < Metaclastic < Metasedimentary < Metamorphic Indeterminate, major