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Geologic Unit: Akmalik
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Map showing publication footprint
  • Usage in publication:
    • Akmalik Chert
  • Modifications:
    • Named
    • Reference
    • Biostratigraphic dating
  • Dominant lithology:
    • Chert
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Mull, C.G., Crowder, R.K., Adams, K.E., Siok, J.P., Bodnar, D.A., Harris, E.E., Alexander, R.A., and Solie, D.N., 1987, Stratigraphy and structural setting of the Picnic Creek allochthon, Killik River quadrangle, central Brooks Range, Alaska; a summary, IN Tailleur, I.L., and Weimer, Paul, eds., Alaskan North Slope geology; Volume 2: Society of Economic Paleontologists and Mineralogists, Pacific Section, North Slope Seminar II, AAPG/SEPM/SEG Pacific Section annual meeting, Anchorage, AK, May 22-24, 1985, book 50, p. 649-662., Prepared by SEPM Pacific Section and Alaska Geol. Soc


Summary:

Named as formation in Lisburne Group. Extensively exposed in Kurupa Hills and in Imnaitchiak and Akmalik Creeks area. Type locality designated in canyon of Akmalik Creek, sec.30 T12S R10N, U.P.M. (Killik River quad) about 2 mi (3.2 km) southwest of Kikiktat Mountain, central Brooks Range, northern AK. Reference section is in Kurupa Hills, sec.29 T12S R12W, U.P.M. Contains rocks previously designated "black Lisburne". Consists of bedded black chert with minor amounts of siliceous black mudstone and interbedded black shale. Orange- and red-brown streaks stain surface of chert due to oxidation of included pyrite. Is between 230 and 260 ft thick in Killik River area. Base not well exposed but apparently gradationally overlies Kayak Shale of Endicott Group. Underlies Imnaitchiak Chert (new) of Etivluk Group. Age is considered to be Mississippian to Early Pennsylvanian based on plant fossils, radiolarians and conodonts.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Akmalik Chert*
  • Modifications:
    • Adopted
    • Age modified
    • Biostratigraphic dating
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Moore, T.E., Wallace, W.K., Bird, K.J., Karl, S.M., Mull, C.G., and Dillon, J.T., 1994, Geology of northern Alaska, Chapter 3, IN Plafker, George, and Berg, H.C., eds., Geology of Alaska: Geological Society of America, The Geology of North America, The Decade of North American Geology (DNAG), v. G-1, p. 49-140.


Summary:

Akmalik Chert of Lisburne Group of Mull and others (1987) is adopted. Consists of bedded, black, spiculite chert with black shale partings with minor amounts of siliceous black mudstone and rare dolomitic limestone beds. Age is Late Mississippian (Meramecian and Chesterian) and Early Pennsylvanian (Morrowan); indicated by radiolarian and conodont assemblages and a plant fossil.

Source: GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Akmalik Chert*
  • Modifications:
    • Age modified
    • Biostratigraphic dating
  • AAPG geologic province:
    • Alaska Northern region
Publication:

Blome, C.D., Reed, K.M., and Harris, A.G., 1998, Radiolarian and conodont biostratigraphy of the type section of the Akmalik Chert (Mississippian), Brooks Range, Alaska, IN Gray, J.E., and Riehle, J.R., eds., Geologic studies in Alaska by the U.S. Geological Survey, 1996: U.S. Geological Survey Professional Paper, 1595, p. 51-69.


Summary:

Akmalik Chert of Lisburne Group. Age is restricted to Early to Late Mississippian (middle Osagean to probably late Meramecian; late Tournaisian to Visean) based on conodonts and radiolarians identified from the type section and its counterpart on opposite side of Akmalik Creek (Lat. 68 deg. 23.13 min. N., Long. 154 deg. 19.2 min. W., Killik River quadrangle), and a partial section along an unnamed tributary to Akmalik Creek about 0.2 km to west. Lower part of Akmalik lies within the conodont S. ANCHORALIS-D. LATUS zone of Poole and Sandberg, 1991 (Pacific Sec. SEPM Book 67, p. 107-136), upper part lies within the radiolarian A. CARALLA zone of Won, 1991 (Paleo. Soc. Korea Jour., v. 7, no. 1, p. 13-25).

Source: Publication.


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