Wilcox, Paul S; Mudelsee, Manfred; Spötl, Christoph; Edwards, R Lawrence (2022): Thorium-230 dating of speleothems WB-21-5-A and WA-21-6-A [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.949766, In: Wilcox, PS et al. (2022): WA-21-6-A and WB-21-5-A speleothem geochemistry [dataset bundled publication]. PANGAEA, https://doi.org/10.1594/PANGAEA.949778
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Published: 2022-10-18 • DOI registered: 2022-11-16
Abstract:
The dataset includes speleothem U-Th ages used to reconstruct climate in southeastern Alaska during the past ~3,500 years. Speleothem WB-21-5-A was collected in Wishbone Cave (55.774 N, -133.191 E; 420 m.a.s.l.) and speleothem WA-21-6-A was collected in Walkabout Cave (55.776° N, 133.195° W; 350 m.a.s.l.) on May 21, 2022 and June 21, 2022, respectfully. The data collection was completed between September 2021-March 2022. U-Th ages were measured on a ThermoFisher Neptune Plus multi-collector inductively coupled plasma mass spectrometer.
Further details:
Cheng, Hai; Edwards, R Lawrence; Shen, Chuan-Chou; Polyak, Victor J; Asmerom, Yemane; Woodhead, Jon D; Hellstrom, John C; Wang, Yongjin; Kong, Xinggong; Spötl, Christoph; Wang, Xianfeng; Alexander, E Calvin (2013): Improvements in 230Th dating, 230Th and 234U half-life values, and U–Th isotopic measurements by multi-collector inductively coupled plasma mass spectrometry. Earth and Planetary Science Letters, 371-372, 82-91, https://doi.org/10.1016/j.epsl.2013.04.006
Jaffey, A H; Flynn, K F; Glendenin, L E; Bentley, W C; Essling, A M (1971): Precision measurement of half-lives and specific activities of 235U and 238U. Physical Review C, 4(5), 1889-1906, https://doi.org/10.1103/PhysRevC.4.1889
Funding:
Coverage:
Median Latitude: 55.775000 * Median Longitude: -133.193000 * South-bound Latitude: 55.774000 * West-bound Longitude: -133.195000 * North-bound Latitude: 55.776000 * East-bound Longitude: -133.191000
Date/Time Start: 2022-05-21T00:00:00 * Date/Time End: 2022-06-21T00:00:00
Minimum DISTANCE: 0.50 cm * Maximum DISTANCE: 53.60 cm
Event(s):
Comment:
U decay constants: l238 = 1.55125x10-10 (Jaffey et al., 1971) and l234 = 2.82206x10-6 (Cheng et al., 2013).
Th decay constant: l230 = 9.1705x10-6 (Cheng et al., 2013).
* d234U = ([234U/238U]activity – 1)x1000
d234Uinitial was calculated based on 230Th age (T), i.e., d234Uinitial = d234Umeasured x el234xT.
** Corrected 230Th ages assume the initial 230Th/232Th atomic ratio of 4.4 ±2.2 x10-6. Those are the values for a material at secular equilibrium, with the bulk earth 232Th/238U value of 3.8. The errors are arbitrarily assumed to be 50%.
*** B.P. stands for “Before Present” where the “Present” is defined as the year 1950 CE.
Parameter(s):
| # | Name | Short Name | Unit | Principal Investigator | Method/Device | Comment |
|---|---|---|---|---|---|---|
| 1 | Event label | Event | Wilcox, Paul S | |||
| 2 | DISTANCE | Distance | cm | Wilcox, Paul S | Geocode | |
| 3 | Uranium-238 | 238U | µg/kg | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | ppb |
| 4 | Uranium-238, standard deviation | 238U std dev | ± | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | 2 sigma |
| 5 | Thorium-232 | 232Th | ng/kg | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | ppt |
| 6 | Thorium-232, standard deviation | 232Th std dev | ± | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | 2 sigma |
| 7 | Thorium-230/Thorium-232 ratio | 230Th/232Th | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | ||
| 8 | Thorium-230/Thorium-232 ratio, standard deviation | 230Th/232Th std dev | ± | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | 2 sigma |
| 9 | δ234 Uranium | δ234U | ‰ | Wilcox, Paul S | Measured | * |
| 10 | δ234 Uranium, standard deviation | δ234U std dev | ± | Wilcox, Paul S | Measured | 2 sigma |
| 11 | Thorium-230/Uranium-238 activity ratio | (230Th/238U) | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | ||
| 12 | Thorium-230/Uranium-238 activity ratio, standard deviation | (230Th/238U) std dev | ± | Wilcox, Paul S | MC-ICP-MS (Thermo Scientific, Neptune) | 2 sigma |
| 13 | Age, dated | Age dated | ka | Wilcox, Paul S | Age, 230Thorium, uncorrected | |
| 14 | Age, dated, standard deviation | Age dated std dev | ± | Wilcox, Paul S | Age, 230Thorium, uncorrected | 2 sigma |
| 15 | Age, dated | Age dated | ka | Wilcox, Paul S | Age, 230Thorium, corrected | |
| 16 | Age, dated, standard deviation | Age dated std dev | ± | Wilcox, Paul S | Age, 230Thorium, corrected | 2 sigma |
| 17 | δ234 Uranium (0) | δ234U (0) | ‰ | Wilcox, Paul S | Corrected | ** |
| 18 | δ234 Uranium (0), standard deviation | δ234U (0) std dev | ± | Wilcox, Paul S | Corrected | 2 sigma |
| 19 | AGE | Age | ka BP | Wilcox, Paul S | Corrected | Geocode – *** |
| 20 | Age, standard deviation | Age std dev | ± | Wilcox, Paul S | Corrected | 2 sigma |
License:
Creative Commons Attribution 4.0 International (CC-BY-4.0)
Status:
Curation Level: Enhanced curation (CurationLevelC) * Processing Level: PANGAEA data processing level 3 (ProcLevel3)
Size:
170 data points