Seabee Formation and Hue Shale

Unit symbol: Ksbf
Age range Upper Cretaceous, Coniacian to Turonian (93.9 to 86.3 Ma)
Lithology: Sedimentary
Group name: Seabee Formation and Hue Shale
Bentonitic mudstone, silty mudstone, and medium- to dark-gray to black, fissile, organic-rich shale containing interbedded bentonite and some thin, silicified tuff beds. Some localities characterized by large, yellowish-brown-weathering ovoid concretions greater than 3 ft (90 cm) in diameter. Unit consists only of rocks formerly mapped as Shale Wall Member of the Seabee Formation by Detterman and others (1963); other members have been abandoned. Unit defined by Gryc and others (1951) and Whittington (1956) and revised by Mull and others (2003). Map unit here also includes Hue Shale of Molenaar and others (1987), which consists of dark-gray, bentonitic shale in which fine-grained pyroclastic rock fragments weather yellow and greenish gray, and, in areas surrounding Sadlerochit Mountains, bright red. As mapped in Ignek Valley, includes some interbedded turbiditic shale and sandstone assigned to the Canning Formation. Interpreted by Molenaar and others (1987) to be a distal marine deposit and a condensed section; its upper parts may be equivalent in part with the lower part of the Canning Formation. The rocks of now-abandoned Ignek Formation are also included here; it consisted of a lower member of siltstone, shale, and locally fossiliferous subgraywacke sandstone; and an upper member, predominantly shale and lesser sandstone and siltstone beds, characterized by abundant pyroclastic deposits (Keller and others, 1961)

Source map information

Source map Reiser, H.N., Brosge, W.P., Dutro, J.T., Jr., and Detterman, R.L., 1971, Preliminary geologic map, Mt. Michelson quadrangle, Alaska: U.S. Geological Survey Open-File Report 71-237, 2 sheets, scale 1:200,000.
Symbol Kp
Unit name Pyroclastic rocks
Description Silicified tuff and bentonitic shale; minor silty shale. Weathers red and green. Locally includes underlying black organic shale.
Lithology Sedimentary

Correlated geologic units

Label Ksbf
Description Seabee Formation (now only former Shale Wall Member)
Geologic age Cenomanian to Coniacian
Geologic setting Sedimentary, deltaic-and-nearshore
Lithology Form Importance
Shale < Mudstone < Clastic < Sedimentary Carbonaceous Major
Bentonite < Claystone < Mudstone < Clastic < Sedimentary Bed Indeterminate, major