| Sample: |
Sample No. 69A13g -- USGS No. 8741-SD
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| Locality: |
Field No. 69A13g
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| Description: |
67o 03.2', 156o 56.7', Cosmos Hills, Ambler River quadrangle, collections of the 69A series were made by C.E. Fritts of the Alaska Geological Survey and are marked (without numbers) on Fritts' map (1970, fig. 4a) (data from Oliver et al., 1975, p. 28, 35) |
| Location: |
Alaska Quadrangle: Ambler River A-2
Lat.: 67o03.2 ' Long.: 156o56.7 ' |
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Reference
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| Title: |
Ordovician, Silurian, and Devonian corals of Alaska
,
1975
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Abstract Corals are common in Ordovician, Silurian, and Devonian rocks from Alaska, but few have been described or illustrated. Most of the known occurrences of corals are in carbonate rocks, either in an east-west belt of shelf facies across central Alaska that presisted from pre-Ordovician to Middle Devonian time or in a more southerly volcanic graywacke belt of geosynclinal facies that includes significant limestone units in southeastern Alaska. Corals occur in other areas but are less well known.
Annotated lists of corals summarize most collections made by U.S. Geological Survey geologists in the last 15 years. Many of the corals are illustrated. |
| Report by: |
William A. Oliver
, Jr.
,
C. W. Merriam
,
Michael Churkin
, Jr.
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| | Age: | Devonian |
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| Comment: | A limestone-dolomite unit of Devonian age, referable to the Baird Group, has been mapped along the south edge of the Brooks Range, particularly in the Cosmos Hills and Jade Mountains in the southern part of the Ambler River (1:250,000) quadrangle (fig. 11, area 2)(Patton and others, 1968; see also Fritts, 1970, who covers part of this area in greater detail). These rocks are mostly of Early and Middle Devonian age (Emsian, Eifelian, and Givetian?), as indicated by Emmonsia, Diplochone, Pseudotryplasma, and Taimyrophyllum in various collections. Late Devonian rocks are probably included in some places (J.T. Dutro, Jr., oral commun., 1972), but of the corals, only the possible Smithophyllum in one collection is suggestive of the Frasnian. Older Devonian (pre-Emsian) or even Silurian faunas may be represented by collection 7983-SD (with Tryplasma). Corals in this group of collections are poorly preseved and species-level comparisons are made in only a few cases (table 8). (from Oliver et al., 1975, p. 27-28). |
| Occurrence(s) |
| No. |
Group |
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Name |
Qty |
Notes |
| 1 |
Tabulate Corals |
|
Favosites sp. |
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