Sample: Jensen_2008_Chester_Bluff_Tom_King_tephra
| Sample ID: |
Jensen_2008_Chester_Bluff_Tom_King_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: |
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| Collector: |
Jensen, B. J. L. |
| Date sampled: |
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| Sample type 1: |
Tephra Fall |
| Color: |
pink-gray |
| Final unit: |
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| Text Description: |
Present at Site B and Site C of Chester Bluff. At Site B, Tom King (TK), MC, PrH, Ben Creek (BC) and Yukon Tanana (YT) are found within 2m of one another. SR, TK, MC and PrH are deposited within greyish brown loess 0.5 to 1m below a major organic unit that contains BC and YT. At the downstream end of the 6m lateral section the tephra beds are reworked and faulted downward. At the upstream end, the major organic unit above SR, TK, MC and PrH is deformed along its base, causing the tephra beds to be overturned and partially reworked into the base of the unit. A 6m wide trench was excavated to fully delineate the tephrostratigraphic relations of the six tephra beds. TK is 15 to 20 cm above SR and forms a continuous, diffuse, pink-gray bed up to 0.5 cm thick. At Site C, the reworked PrH/MC and TK are found as an isolated pod. Low percentage of phenocrysts (<20%) and contain a population of distinctively thick-walled pumice and glass shards. Glass fractions are rich in microcrysts. The composition reported was calculated from analyses of three samples: UA1086, UA1219, and UA1224. |
| 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.