| Sample: |
Sample No. 54AKe1 -- USGS No. Mesozoic loc. 25276
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| Locality: |
Field No. 54AKe1
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| Description: |
170 to 230 feet above the top of Chisik conglomerate. Northeast side of Grosvenor Lake, Lat. 58o 41' N., Long. 155o 07' W., Alaskan Peninsula (from E&R report); USGS Mesozoic locs. 25276-25278 and M 2076. On northeast side of Grosvenor Lake, lat 58°41' N., long 155°7'-10' W., Mt. Katmai quadrangle, Alaska Peninsula. Buchia rugosa (Fischer) and B. mosquensis (von Buch) range from just below Chisik Conglomerate Member of Naknek Formation (loc. M 2076) to 530 feet above (loc. 25277). (description from Imlay and Detterman, 1973, p. 27);[USGS Mes. Cat.: 25276. 54AKe1. Upper Jurassic, Naknek Formation, 170' to 230' above top of Chisik cg. in green to light gray arkosic ss. Lat. 58°41' N., Long. 155° 07' W., northeast of Grosvenor Lake, Katmai quad, Subdivision C4., Alaskan Peninsula, Alaska] |
| Location: |
Alaska Quadrangle: Mt Katmai C-4
Lat.: 58o41' " Long.: 155o07' " |
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Reference
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| Title: |
Report on Referred Fossils
,
1954
(11/08)
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The fossils from the Naknek formation belong in the zone of Aucella rugosa (Fischer). There is no representative of the older zone characterized by Aucella concentrica (Fischer)(equals A. bronni or the still older zone characterized by species of Cardioceras. The latter has never been found on the Alaska Peninsula, but the zone of A. concentrica is widespread. In the Talkeetna Mountains the base of the zone with Aucella rugosa is near the middle of the Naknek in the southern exposures but occupies the base of the formation in the northernmost exposures. Similar overlap relationships should be considered in future field work on the Naknek formation of the Alaska Peninsula. The fossils from the Kaguyak formation are of Campanian or Maestrichtian age and are younger than any fossils found in the Chignik formation in the southern part of the Alaska Peninsula. In the Talkeetna Mountains fossils identical with those in the Kaguyak formation occur at the top of the siltstone member of the Matanuska formation just below the highest sandstone member. The smooth compressed pachydiscid ammonite from locality 54AKe41 is good evidence of a postion high in the Upper Cretaceous sequence. The small Inoceramus with sharp, equally-spaced ribbing that is compared with I. kusiorensis Nagao and Matumoto is likewise common the high Cretaceous beds. Several years ago I examined an excellent collection from the Kaguyak area made by John Hazzard and associates of the Union Oil Company. A copy of that report can be sent to you if you so desire. |
| Report by: |
Ralph W. Imlay
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| Referred by: |
A. S. Keller
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| | Age: | Late Jurassic |
| Formation: | Naknek Formation |
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| Comment: | The fossils from the Naknek formation belong in the zone of Aucella rugosa (Fischer). There is no representative of the older zone characterized by Aucella concentrica (Fischer)(equals A. bronni or the still older zone characterized by species of Cardioceras. The latter has never been found on the Alaska Peninsula, but the zone of A. concentrica is widespread. In the Talkeetna Mountains the base of the zone with Aucella rugosa is near the middle of the Naknek in the southern exposures but occupies the base of the formation in the northernmost exposures. Similar overlap relationships should be considered in future field work on the Naknek formation of the Alaska Peninsula. |
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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
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Robert L. Detterman
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| | Age: | Kimmeridgian-Tithonian (late Kimmeridgian - early middle Tithonian) |
| Formation: | Naknek Formation |
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| Comment: | Generalized locality shown as locality 20 in figure 8 |
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