Data Release for Luminescence: Floodplain Sediment Storage Timescales of the Laterally Confined Meandering Powder River, U.S.A
Dates
Publication Date
2022-03-30
Start Date
2015
End Date
2020
Citation
Mahan, S.A., Gray, H.J., and Krolczyk, E.T., 2022, Data Release for Luminescence: Floodplain Sediment Storage Timescales of the Laterally Confined Meandering Powder River, U.S.A: U.S. Geological Survey data release, https://doi.org/10.5066/P9GOLM7U.
Summary
The following report summarizes the dating results from the. Within this report, we detail the methodology used to determine the storage time distribution for a 17 km length of Powder River in Montana, U.S.A. by the age distribution of eroded sediment. This data is used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating-related 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.
Summary
The following report summarizes the dating results from the. Within this report, we detail the methodology used to determine the storage time distribution for a 17 km length of Powder River in Montana, U.S.A. by the age distribution of eroded sediment. This data is used by the USGS Luminescence Geochronology Laboratory to obtain ages including sample preparation methods, luminescence measurement, equivalent dose determination, and dating-related 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.
Luminescence dating was begun on the Powder River fluvial terrace sediments in March 2014. The goal was to see if the depositional time of the sediments could be dated accurately as well as precisely using luminescence on quartz mineral separates (OSL). Several unique terrace levels had been identified along the River. The youngest is the “Lightening Terrace” with small cottonwood trees adjacent to the floodplain. The second is the “Moorcroft Terrace” with large cottonwood trees and the third is a colluvial “Kaycee Terrace” that grades slowly upwards meeting the hills of the Fort Union Formation. OSL dating should be able to put times of formation to these terraces as well as identify any larger flood deposits that subsequently modified the terraces. Throughout 2014 to 2019 the USGS Luminescence Geochronology measured at least some luminescence data for almost 50 samples and there was approximately 90 samples collected expressly for luminescence dating (PR-88 the last sample we know of).