TABLE A1. Accelerator mass spectrometry (AMS) radiocarbon dates on plant macrofossils and volcanic tephras with known ages from the Cooley Lake and Rockslide Lake sediment cores. Tephra identifications and radiocarbon dates were previously published in Foit et al. (2004).
Depth (cm) |
Laboratory number or tephraa |
14C age |
Calibrated age (cal. yr BP)b |
Cooley Lake |
|||
50.5-51.3 |
St. Helens Wn |
- |
468c |
95.0-95.5 |
Beta-157960 |
1590±50 |
1350-1570 |
171.0-172.0 |
CAMS-95388 |
2530±45 |
2470-2750 |
199.0-200.0 |
CAMS-85222 |
3010±60 |
3060-3350 |
326.0-327.0 |
CAMS-85223 |
5195±40 |
5900-6000 |
> 377.0 |
Mazama O |
- |
7627d |
Rockslide Lake |
|||
22.0-22.7 |
St. Helens Wn |
- |
468c |
62.0-62.5 |
CAMS-97111 |
1970±35 |
1860-1990 |
92.0-93.0 |
St. Helens P |
- |
2620e |
128.5-129.0 |
CAMS-97112 |
3360±40 |
3470-3690 |
168.0-168.5 |
CAMS-97113 |
3870±60 |
4140-4420 |
202.0-202.5 |
CAMS-98368 |
4420±45 |
4870-5280 |
> 221.0 |
Mazama O |
- |
7627d |
aBeta=Beta Analytic, Inc.; CAMS=Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory. Tephra names in italics.
bMinimum and maximum of 2 SD age ranges only, rounded to nearest decade. Calibration follows Stuiver and Reimer 1993 (Rev 4.4) and Stuiver et al. 1998.
cFrom Yamaguchi (1983).
dFrom Zdanowicz et al. (1999).
eFrom correlation with Cooley Lake; Foit et al. (2004).
LITERATURE CITED
Foit, F. F., D. G. Gavin, and F. S. Hu. 2004. The tephra stratigraphy of two lakes in South-central British Columbia, Canada and its implications for the mid-late Holocene volcanic activity at Glacier Peak, Washington, USA. Canadian Journal of Earth Sciences 41:14011410.
Stuiver, M., and P. J. Reimer. 1993. Extended 14C database and revised CALIB radiocarbon calibration program. Radiocarbon 35:215230.
Stuiver, M., P. J. Reimer, E. Bard, J. W. Beck, G. S. Burr, K. A. Hughen, B. Kromer, G. McCormac, J. Van der Plicht, and M. Spurk. 1998. INTCAL98 radiocarbon age calibration, 24,000-0 cal BP. Radiocarbon 40:10411083.
Yamaguchi, D. K. 1983. New tree-ring dates for recent eruptions of Mount St Helens. Quaternary Research 20:246250.
Zdanowicz, C. M., G. A. Zielinski, and M. S. Germani. 1999. Mount Mazama eruption: Calendrical age verified and atmospheric impact assessed. Geology 27:621624.