Sample: Jensen_2008_Chester_Bluff_Old_Crow_tephra
| Sample ID: |
Jensen_2008_Chester_Bluff_Old_Crow_tephra [1] [2] |
| Station ID: |
Jensen_2008_Chester_Bluff |
| AT Num: |
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| Volcano: |
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| Possible source: |
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| Eruption: |
Old Crow Tephra |
| Collector: |
Jensen, B. J. L. |
| Date sampled: |
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| Sample type 1: |
Tephra Fall |
| Color: |
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| Final unit: |
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| Text Description: |
Present at Site B and Site C of Chester Bluff. At Site B, the OC tephra is separated from a >/~ 1 m thick organic unit overlying the th BS tephra by 5m of remobilized, massive, inorganic loess. OC is up to 25 cm thick and continuous across the bluff. The base of the tephra has a sharp contact and is Fe-stained; the upper contact is diffuse and partially reworked. At Site C, the OC is present approximately 30m downstream from the main stratigraphic section. It is up to 10 cm thick and heavily reworked within dark brown organic-rich silt. OC can be traced laterally for over 10 m, and rises steeply towards the top of the upstream end of the bluff. Although OC could not be traced to the main excavated trench at Site C, its projected position stratigraphically overlies BT. Low vesicular pumice, bubble-walled and tri-cuspate shards. The composition reported was calculated from analyses of three samples: UA1099, UA1233, and UA1211. |
| Sample Location: |
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References Cited
Jensen, B.J.L., Froese, D.L., Preece, S.J., Westgate, J.A., and Stachel, Thomas, 2008, An extensive middle to late Pleistocene tephrochronologic record from east-central Alaska: Quaternary Science Reviews, v. 27, p. 411-427, doi:10.1016/j.quascirev.2007.10.010 .
Jensen, B.J.L., 2007, Tephrochronology of Middle to Late Pleistocene Loess in Eastcentral Alaska: University of Alberta M.S. thesis, 120 p.