Report on Referred Fossils |
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Stratigraphic range: |
Callovian (late Middle Jurassic) |
Kinds of fossils: |
Mollusks |
Quadrangle or area: |
Karluk and Ugashik quads. |
Shipment No.: |
A-81-11B |
Referred by: |
Detterman, Robert L.
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Report prepared by: |
Imlay, Ralph W.
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Date: |
02/19/1981 |
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SHELIKOF FORMATION Ages of the Shelikof Formation between Wide Bay and Puale Bay based on ammonites The ammonites collected in 1980 from the Shelikof Formation on the Alaska Peninsula represent most the same taxa that were collected previously (Imlay, Prof. Paper 836, p. 3, 7, 12, 13) except for the absence of Kepplerites and the presence of Xenocephalites. Among the genera present, Pseudocadoceras in Europe (Prof. Paper 836, fig. 7) ranges from the upper part of the lower Callovian to the top of the Callovian. In southern Alaska Pseudocadoceras occurs in the upper three fourths of the Chinitna Formation in beds that are dated as late early and middle Callovian (See Prof. Paper 836, p. 6, 14). On the Alaska Peninsula Pseudocadoceras ranges from the very top of the lower member of the Shelikof Formation into the basal beds of the upper member and is dated as mainly of middle Callovian age (Prof. Paper 836, p. 12, 14). Stenocadoceras in Europe ranges upward from upper lower Callovian to the lower part of the upper Callovian (Prof. Paper 836, fig. 7 on p. 13). Stenocadoceras in southern Alaska has stratigraphic and age ranges identical with those of Pseudocadoceras. Cadoceras in Europe and in Alaska ranges through beds of early and middle Callovian ages, but the species Cadoceras catostoma Pompeckj in Alaska has been found ony in beds of early Callovian age. Iniskinites and Xenocephalites west of Cook Inlet occur throughout much of the Bowser Formation of Bathonian age. They occur also in the basal beds of the Chinitna and Shelikof Formations which are of earliest Callovian rather than latest Bathonian age based on their associations with Cadoceras (See Prof. Paper 1091, p. 14-16 and PP. 836, p. 6). In summation, most of the ammonites collected in 1980 from the Shelikof Formation were obtained from the middle member and are of middle Callovian age. Ammonites that are definitely of early Callovian age include Cadoceras catastoma Pompeckj at localities 80ADt216 and 80ADt216A, Xenocephalites at locality 80ADt239, and Iniskinites at locality 80ACe153. Elsewhere in southern Alaska, Cadoceras catostoma has been found only in beds of early Callovian age; Xenocephalites ranges upward through most of the Bathonian sequence (see Prof. Paper 1091, figs. 2 and 5) but occurs also into the basal beds of the Chinitna Formation; and Iniskinites ranges upward through the late middle to late Bathonian sequence into the basal beds of the Chinitna Formation. Neither Xenocephalites or Iniskinites range into the basal part of the range of Cadoceras catostoma (see Prof. Paper 836, p. 12, 14, and Prof. Paper 1091, p. 14). AMMONITE TAXA IN THE SHELIKOF FORMATION LISTED BY LOCALITIES Phylloceras bakeri - 80ACe224, 80AAy1. Phylloceras cf. P. bakeri Imlay - 80ADt 238D Phylloceras sp. - 80ACe222 Xenocephalites hebetus Imlay - 80ADt239 Lilloettia stantoni Imlay - 80ADt216A Lilloettia sp. - 80AJm13A Iniskinites sp. - 80AJm13A Cadoceras wosnessenskii (Grewingk) - 80ACe185, 185B, 198; 80ADt216 Cadoceras catostoma Pompeckji - 80ACe185, 185B, 198; 80ADt216 Catostoma tenuicostatum Imlay - 80AAy60A, 80ACe198 Cadoceras spp. - 80ACe105, 80AAy60, 80ACx30 Cadoceras? sp. 80ACx19, 80AJm7 Cadoceras (Stenocadoceras) cf. C. (S).) striatum Imlay - 80ACe119, 80AJm8 C. (Stenocadoceras) stiatum Imlay - 80AWs249 C. (Stenocadoceras) multicostatum Imlay - 80ACe147, 151B, 205A, 220, 222, 80AAy1, 60, 60A C. (Stenocadoceras) cf. C. (S.) multicostatum Imlay - 80ADt204, 211, 275, 245 C. (Stenocadoceras) iniskinense Imlay - 80ADt338C C. (Stenocadoceras) cf. C. (S). iniskinense Imlay - 80ACe205A C. (Stenocadoceras) stenoloboide Pompeckj - 80ADt245 C. (Stenocadoceras) cf. C. (Stenocadoceras) stenoloboide Pompeckj - 80ADt238B, Fs 2 on Helen Creek. Cadoceras (Stenocadoceras) sp. - 80ADt238D, 80AJm1 C. (Stenocadoceras?) sp. - 80ADt274 Pseudocadoceras petelini (Pompeckj) - 80ACe105, 111, 113A; 80ADt181, 202, 203, 291, 265; 80AAy82 Pseudocadoceras cf. P. petelini (Pompeckj) - 80ACe220, 80ADt238A Pseudocadoceras cf. P. schmidti (Pompeckj) - 80ACe185A Pseudocadoceras grewingki (Pompeckj) - 80ACe220, 80ADt181, 202, 265, 80AJm7 Pseudocadoceras crassicostatum Imlay - 80AAy82 Pseudocadoceras sp. - 80ADt238B
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User Note module to be added |
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80AWs249
, Karluk
, Karluk D-4 quad., sec. 14, T. 27 S., R. 36 W., lat. 57 deg. 51 min. 23 sec. N., long. 155 deg. 09 min. 00 sec. W., 2.8 miles S. 64 deg. W. of tri. sta. Kubugakli, shale
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Cadoceras (Stenocadoceras) striatum Imlay
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80AWs255
, Karluk
, Karluk C-6 quad., sec. 20, T. 28 S., R. 39 W., lat. 57 deg. 44 min. 38 sec. N., long. 155 deg. 42 min. 43 sec. W., 3.9 miles N. 47 deg. W. of tri. sta. Trail (Karluk C4 & C5 quad.), siltstone.
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80AJm1
, Karluk
, Karluk D-5 quad. Along beach south of Helen Creek at base of coastline cliff in NW 1/4 sec. 23, T. 28 S., R. 38 W. Pebbly sandstone stringer in massive sandstone.
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Cadoceras (Stenocadoceras) sp.
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80AJm6
, Karluk
, Karluk D-5 quad. Siltstone. About 50 ft. below contact with Naknek Formation. About 800 ft. N., 450 ft. E. of SW corner sec. 10, T. 28 S., R. 38 W.
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80AJm7
, Karluk
, Karluk D-5 quad., Red-gray interbedded sandstone and siltstone. About 250 ft. south, 200 ft. west of NE corner sec. 20, T. 28 S., R. 37 W.
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Pseudocadoceras grewingki (Pompeckj)
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80AJm8
, Karluk
, Karluk D-5 quad., Massive sandstone. 1,700 ft. south, 100 ft. west of NE corner sec. 23, T. 28 S., R. 38 W.
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Cadoceras (Stenocadoceras) cf. C. (S.) striatum Imlay
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80AJm13
, Karluk
, Karluk D-5 quad., massive sandstone. About 600 ft. north, 1,800 ft. east of SW corner sec. 16, T. 28 S., R. 37 W.
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80AJm13A
, Karluk
, same as 13 except float from pebbly conglomerate from a few feet above.
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Fs 2 (unknown person)
, Karluk
, Karluk D-5 quad., along beach on south side of Helen Creek in NW 1/4 sec. 23, T. 28 S., R. 38 W., northeast of Puale Bay. (cited in E&R report as "Fossil from the Shelikof Formation collected on Helen Creek northeast of Paule Bay by an unknown person".
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Cadoceras (Stenocadoceras) cf. C. (S.) stenoloboide Pompeckj
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