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Reference
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| Title: |
Report on Referred Fossils
,
1971
(08/24)
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The fossil collections described in letters dated July 6 and 19, 1971 are probably in part of Triassic age as indicated by the presence of monotid pelecypods at locality 71ADt283. The Pliensbachian is represented definitely by Amaltheus at locality 71ADt300C. The late Bathonian, as defined by John Callomon, is represented by Arcticoceras at locality 71ADt330D (or 300D). The Cadoceras from that locality has a black instead of a reddish-brown matrix and appears to have been rounded by rolling. It reminds me of Cadoceras comma Imlay from southern Alaska. It probably comes from higher beds than Arcticoceras, judging by the ranges of those genera in northern Canada and east Greenland. The late Jurassic (middle Kimmeridgian to early Tithonian) is represented by Buchia rugosa (Fischer) at locality 71ADt322. The Buchias from localities 71ADt325 and 325A are probably not specifically determinable but will be sent to Dave Jones. The monotid from locality 71ADt283, will be sent to Norm Silberling. Please check Mes. Loc. 30075 in order to determine proper field number. Also, check all stratigraphic and geographic descriptions and revise as needed. I would like to have your opinion considering the relative stratigraphic positions of Arctocephalites and Reineckeia in the sequence near the Canning River as measured by the BP geologists. Is the position of Arctocephalites above Reineckeia normal or is it due to faulting or folding? |
| Report by: |
Ralph W. Imlay
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| Referred by: |
Robert L. Detterman
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| | Age: | No Data |
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| Comment: | The Buchias from localities 71ADt325 and 325A are probably not specifically determinable but will be sent to Dave Jones. |
| Occurrence(s) |
| No. |
Group |
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Name |
Qty |
Notes |
| 1 |
Bivalves |
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Buchia sp. |
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| Title: |
Jurassic Paleobiogeography of Alaska
,
1973
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ABSTRACT: Jurassic marginal seas occupied considerable areas in southern and northern Alaska and in the western part of the Kuskokwim region of southwestern Alaska. They appear to have been absent during late Callovian time, much restricted during Hettangian, Bathonian, early Oxfordian and late Tithonian time, and most extensive during Sinemurian, Bajocian, and late Oxfordian to middle Tithonian time. A large area in central Alaska was probably never covered. A southwestern prolongation of that area from the Talkeetna Mountains westward to the western end of the Alaska Penin- sula was the site of granitic intrusions during late Early Jurassic time and of extensive erosion during Middle and Late Jurassic time. Variations in the rate of uplift of the area of these granitic intrusive rocks may explain why marine transgressions and regressions were at different times in southern than in northern Alaska during the Bajocian and Bathonian. Connection of the northern and southern marginal seas occurred through Yukon Territory and eastern- most Alaska. The Jurassic ammonite succession in Alaska is similar to that in central and northern Europe and northern Asia. In Lower Jurassic beds, it is essentially identical. In Bajocian and in Oxfordian to lower Kimmeridgian beds, the ammonite succession in Alaska differs from that in the other areas mainly by the presence of some genera found only in areas bordering the Pacific Ocean and by the absence of a few genera common in central and northern Europe. In con- trast, the Bathonian rocks of Alaska contain ammonites, such as Arcticoceras, Arctocephalites, and Cranocephalites, that are widespread in the Arctic region but are unknown in central Europe. Comparisons with the Tithonian of Europe are not possible because ammonites of that age, other than Lytoceras and Phylloceras, are not yet known from Alaska. The Alaskan Jurassic ammonites of late Pliensbachian Age and of Bathonian to early Kimmeridgian Age belong mostly to the Boreal realm and have very little in common with Tethyan realm ammonites such as those found in areas bordering the Mediterranean Sea. |
| Report by: |
Ralph W. Imlay
,
Robert L. Detterman
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| | Age: | Tithonian (late middle to late Tithonian) |
| Formation: | Kingak Shale |
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| Comment: | Generalized locality shown as locality 3 in figure 9 |
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