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DATA RELEASE Part 2: Optical luminescence dating of Bradley Lake, Oregon, tsunami deposits, analytical data for: A maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis

Dates

Publication Date
Start Date
2012-05-18
End Date
2018-12-18

Citation

Nelson, A., Gray, H., Mahan, S., and Krolczyk, E., 2021, DATA RELEASE Part 2: Optical luminescence dating of Bradley Lake, Oregon, tsunami deposits, analytical data for: A maximum rupture model for the central and southern Cascadia subduction zone—reassessing ages for coastal evidence of megathrust earthquakes and tsunamis: U.S. Geological Survey data release, https://doi.org/10.5066/P9YWIDOW.

Summary

The following report summarizes the dating results from Bradley Lake, Oregon. Within this report, we detail the methodology used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and datingrelated calculations. We recommend that this report be included as the supplementary material for any publication(s) that use the ages within this report. This version supersedes all previous age estimates and reports.

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Attached Files

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Data Dictionary - Bradley Lake.csv 9.36 KB text/csv
OREGON Tsunami Alan Nelson Data Final.csv 3.86 KB text/csv

Purpose

Bradley Lake in Western Oregon is a depositional basin located about half a kilometer from the Pacific Ocean. The lake is of interest to Tsunami hazards due to the preservation of Tsunami related deposits that potentially record the timing of Tsunami events. Here, we attempt to date the deposits via luminescence geochronology on samples extracted from coring of the lake sediments. In summary, we find that the quartz is unsuitable for dating and that feldspar based techniques we attempted as an alternative, produce apparent age overestimates. The age overestimates appear prior to the application of fading corrections and the ages are scattered with stratigraphic age inversions where older ages overlie younger ages. We believe these age inversions represent layers with incomplete resetting of luminescence geochronometers due to a lack of adequate sunlight prior to deposition.

Additional Information

Identifiers

Type Scheme Key
DOI https://www.sciencebase.gov/vocab/category/item/identifier doi:10.5066/P9YWIDOW

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