| Sample: |
Sample No. 59ACr87f -- USGS No. 18991-PC
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| Locality: |
Field No. 59ACr87f
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| Description: |
Ml5 - Tupik formation(?) (no other data provided in Dutro E&R Report of 10/13/61 [Shipment A-60-1]; however, transmittal sheet of R.H. Campbell (dated 12/02/1959) provides following: Lat. 68o 07.2' N, Long. 165o 53.7' W. Coords: (7.90; 8.20). |
| Location: |
Alaska Quadrangle: Point Hope A-2
Lat.: 68o07.2 ' Long.: 165o53.7 ' |
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Reference
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| Title: |
Report on Referred Fossils
,
1961
(10/13)
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This report covers 3 collections from the upper part of the Paleozoic sequence in the Point Hope area. Two of the collections, comprising about 60 specimens, are from the Siksikpuk formation and contain elements of the typical fossil assemblage found elsewhere in that rock unit. The age is probably Early Permian as was pointed out in Patton (1957, p. 42). Additional brachiopod genera in these collcetions serve to strengthen that age assignment. The Siksikpuk assemblage is peculariarly limited to a small number of kinds of specialized brachiopods, corals and gastropods. In addition, pyrite is encountered in may places in these strata. The enviornment of depositon clearly was not normal shallow-water marine; it may have been a deedper stater, restricted and reducing regimen. Collection 59ACr87, from the upper part of the Lisburne group, also consists of a small number of specialized forms. They represent the "culm" facies of the Mississippian; it has been found elsewhere in the Brooks Range in the Alapah limestone of the central Brooks Range and in the Tupik formation of the DeLong Mountains region. The age is late Mississippian. I would suggest that unit Ml5 of the measured sequence is a Tupik equivalent. The "culm facies" commonly is applied to the dark shaly phase of the Carboniferous as contrasted to the more normal marine shelly and bioclastic limestones. Some workers have interpreted cephalopod-bearing strata as pelagic. Oths have attributed to pelecypod-rich beds a lagoonal or even deltaic origin. In the north Alaska "culm", deposition is characterized by an influx of clay or silt, as in the shaly limestone member at the base of the Wachsmuth and the shaly limestone and black chert-shale members of the Alapah in the central Brooks Range. The Tupik formation and an unnamed formation in the eastern DeLong Mountains are other examples of this facies. Doubtless, no one mode of origin could explain all these occurrences. In the case of the Point Hope region, I have would suspect that a new source of fine clastic sediment became available late in Mississippian time. The environment changed, becoming unfavorable for the more normal coral-brachiopod assemblage that characterizes many of the Lisburne beds below. Direct evidence is sparse, but the occurrence of Lingula, a generally shallow-water brachiopod, suggests shallow restricted marine basins. As in the Siksikpuk, widespread pyrite in this facies point to recuding conditions, at least in part. |
| Report by: |
J. Thomas Dutro
, Jr.
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| Referred by: |
Russell H. Campbell
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| | Age: | Late Mississippian |
| Formation: | Tupik Formation (Tupik Formation(?) upper part of the Lisburne Group) |
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| Comment: | Collection 59ACr87, from the upper part of the Lisburne group, also consists of a small number of specialized forms. They represent the "culm" facies of the Mississippian; it has been found elsewhere in the Brooks Range in the Alapah limestone of the central Brooks Range and in the Tupik formation of the DeLong Mountains region. The age is late Mississippian. I would suggest that unit Ml5 of the measured sequence is a Tupik equivalent.
The "culm facies" commonly is applied to the dark shaly phase of the Carboniferous as contrasted to the more normal marine shelly and bioclastic limestones. Some workers have interpreted cephalopod-bearing strata as pelagic. Oths have attributed to pelecypod-rich beds a lagoonal or even deltaic origin. In the north Alaska "culm", deposition is characterized by an influx of clay or silt, as in the shaly limestone member at the base of the Wachsmuth and the shaly limestone and black chert-shale members of the Alapah in the central Brooks Range. The Tupik formation and an unnamed formation in the eastern DeLong Mountains are other examples of this facies.
Doubtless, no one mode of origin could explain all these occurrences. In the case of the Point Hope region, I have would suspect that a new source of fine clastic sediment became available late in Mississippian time. The environment changed, becoming unfavorable for the more normal coral-brachiopod assemblage that characterizes many of the Lisburne beds below. Direct evidence is sparse, but the occurrence of Lingula, a generally shallow-water brachiopod, suggests shallow restricted marine basins. As in the Siksikpuk, widespread pyrite in this facies point to recuding conditions, at least in part. |
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| Title: |
Areal Geology in the Vicinity of the Chariot Site, Lisburne Peninsula, Northwestern Alaska
,
1967
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| Report by: |
Russell H. Campbell
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| | Age: | Late Mississippian |
| Formation: | Tupik Formation |
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| Comment: | The Tupik Formation (unit Ml5 of Campbell, 1960a, b) is the topmost formation of the Lisburne Group. .... Fossils are very rare, but a meager fauna was collected (table 2) from one carbonate mudstone bed and detrital fragments are common in some of the microcrystalline limestone beds. The fauna, consisting of gastropods and brachiopods, was examined by J.T. Dutro, Jr., of the Geological Survey, who reports (written commun., 1961) that the age is Late Mississippian. (from Cambell, 1967, p. 19) Tupik Formation ...... (Note by R.B. Blodgett: under Unit 2 of Tupik description) "Fossils rare, generally sparsely disseminated fragments, but one carbonate mudstone beds yielded several gastropods and brachiopods. 59ACr-87f is fossil collection (table 2). 59ACr-87 consists of chips taken to represent lithology. (from Campbell, 1967, p. 34) Collection from Nasorak Creek sea-cliff section. (from faunal list given on Table 2, pp. 8-9 in Campbell, 1967) |
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