Publication Abstracts

Riehle et al. 1992

Riehle, J.R., D.H. Mann, D.M. Peteet, D.R. Engstrom, D.A. Brew, and C.E. Meyer, 1992: The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary. Quat. Res., 37, 183-202, doi:10.1016/0033-5894(92)90081-S.

Late Pleistocene tephra deposits found from Sitka to Juneau and Lituya Bay are assigned to a source near the Mount Edgecumbe volcanic field, based on similarity of glass compositions to near-vent deposits and on thinning away from Kruzof Island. The sequence of near-vent layers is basaltic andesite and andesite at the base, rhyolite, and mixed dacite and rhyolite on top. The only breaks in the tephra sequence are two 1-mm-thick silt partings in a lake-sediment core, indicating a depositional interval from basaltic andesite to dacite of no more than about a millenium. Tephra deposits at sites > 30 km from the vent are solely dacite and rhyolite and are 10,600 to 11,400 14C yr old based on interpretation of 18 radiocarbon ages, including 5 by accelerator mass spectrometry (AMS). Basaltic andesite and andesite deposits nearer the vent are as much as 12,000 yr old.

Discrepancy among radiocarbon ages of upland tephra deposits provisionally correlated as the same grainfall is resolvable within ±2 σ of analytical uncertainty. Comparison of bulk and AMS ages in one sediment core indicates a systematic bias of +600 to +1100 yr for the bulk ages; correlation of tephra deposits among upland and lacustrine sites implies an additional discrepancy of 200-400 yr between upland (relatively too young) and lacustrine ages. In any case, the Mount Edgecumbe tephra deposits are a widespread, latest Pleistocene stratigraphic marker that serves to emphasize the uncertainty in dating biogenic material from southeastern Alaska.

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BibTeX Citation

@article{ri05500b,
  author={Riehle, J. R. and Mann, D. H. and Peteet, D. M. and Engstrom, D. R. and Brew, D. A. and Meyer, C. E.},
  title={The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary},
  year={1992},
  journal={Quat. Res.},
  volume={37},
  pages={183--202},
  doi={10.1016/0033-5894(92)90081-S},
}

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RIS Citation

TY  - JOUR
ID  - ri05500b
AU  - Riehle, J. R.
AU  - Mann, D. H.
AU  - Peteet, D. M.
AU  - Engstrom, D. R.
AU  - Brew, D. A.
AU  - Meyer, C. E.
PY  - 1992
TI  - The Mount Edgecumbe tephra deposits, a marker horizon in southeastern Alaska near the Pleistocene-Holocene boundary
JA  - Quat. Res.
VL  - 37
SP  - 183
EP  - 202
DO  - 10.1016/0033-5894(92)90081-S
ER  -

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