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Reference
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| Title: |
Report on Referred Fossils
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1969
(10/08)
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The fossils from the Kingak Formation exposed in the northeastern part of the Brooks Range are of Early Jurassic to early Oxfordian ages. |
| Report by: |
Ralph W. Imlay
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| Referred by: |
Robert L. Detterman
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| | Age: | Early Jurassic (middle Early Jurassic) |
| Formation: | Kingak Shale |
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| Comment: | The Gryphaea present probably belongs to G. cymbium Lamarck which is typical of the Pliensbachian of Europe. It was found previously (Prof. Paper 274-D, p.82) in the Ignek Valley at Mes. loc. 23748 (ASa214f). The associated species of Oxytoma, which also occurs at Mesozoic loc. 23748, appears to be identical with O. inaequivalvis (Sowerby), a species recorded in Europe from beds of late Sinemurian to Oxfordian age (Cox, 1940, Paleontologia Indica, ser. 9, vol. 3, pt. 3, p. 98-100). The association of these fossils suggest therefore, that Lot 69ADt-105 is of middle Early Jurassic age. |
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| Title: |
Report on Referred Fossils
,
1969
(11/17)
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This report concerns your collection 69ADt-105 which was sent to me from Washington, D.C., by Ralph Imlay at your request. This collection was made from rocks assigned in the field to the basal 18 feet of the Kingak Formation, and these beds directly overlie the rocks assigned to the Shublik Formation (represented by other collections in the 69ADt-105 series) on Fire Creek. According to Ralph this "basal Kingak" collection contains a species of Gryphaea typical of the Pliensbachian and an Oxytoma apparently identical with O. inequivalvis of late Sinemurian and younger Jurassic age. |
| Report by: |
Norman J. Silberling
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| Referred by: |
Robert L. Detterman
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| | Age: | Late Triassic |
| Formation: | Kingak Shale |
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| Comment: | Re-examination of this collection clearly shows that it is identical both faunally and lithologically with previously made collections regarded as representing the uppermost part of the Shublik Formation in the Fire Creek section. These older collections are Tourtelot's collections 68ATo2-27(USGS Mesozoic loc. M5058) regarded as being 380-395 feet above the base of the Shublik and the collections from USGS Mesozoic localities M2650 through M2652 made by BP Company geologists and regarded by them as being 345-360 feet above the base of the Shublik.
The specimens in collection 69ADt105 [the collection is labeled as 69ADt105f in the original Imlay's report and Detterman's transmittal report] that apparently are those identified as Oxytoma by Imlay represent the characteristic upper Norian bivalve Monotis ochotica ochotica (Keyserling). Also present are tow specimens assignable to M. o. densistriata (Teller), which is also an upper Norian form but probably from a lower stratigraphic level than M. o. ochotica. The Gryphaea in this collection could be a species such as G. keilhaui Boehm which is associated with Monotis ochotica in the Upper Triassic of Siberia.
The collection from USGS Mesozoic loc. 23748 (48ASa214), which contains Gryphaea and scraps of ribbed pectenacids that probably are Oxytoma, was also sent from Washington for comparison. Nothing in this colleciton is necessarily Triassic in age, and the original Jurassic assignment looks correct judging from the general character of the faunal assemblage. |
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