MMRB Radiocarbon Data

	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	P	Q
1	(this will be filled in with additional sample and interpretive data)
2	Table 3 from Burkett et al. (2016). Radiocarbon samples from an exposure in a cutbank along Slippery Creek. The exposure exhibits alluvial gravels capped by silt and a 10-15 cm thick organic-ric soil. The soil is overlain by a thin debris flow deposit. The entire sequence is faulted - illustrated by the folded/faulted buried soil and the scarp extending across the bouldery debris flow surface to the northeast. A single block sample was collected from the buried soil and subsamples of the individual organic fractions were collected and dated independently.
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4	Sample Name*	CAMS Lab Number†						14C Age (BP)§		Calibrated age (cal BP)#	Sample material**	Sampled Unit	Submitted sample mass (mg)	Interpretation	Easting	Northing	Elevation (msl)
5	MMRB01-A	166184						3130 ± 140		3685 - 2960	seeds? (a)	buried soil	4.3	Inherited charred material	593596	7010042	1197
6	MMRB01-B	166185						>Modern		NA	very fine roots (b)	buried soil	13.49	Modern roots	593596	7010042	1197
7	MMRB01-C	166186						630 ± 70		684 – 525	wood/twigs/old roots	buried soil	2.8	Recent plant growth at time of debris flow	593596	7010042	1197
8	MMRB01-D ˠ	166187						3065 ± 25		3359 – 3210	charcoal (c)	buried soil	13.1	Inherited charcoal	593596	7010042	1197
9	MMRB01-F	166188						3140 ± 60		3480 – 3182	charcoal (c)	buried soil	11.7	Inherited charcoal	593596	7010042	1197
10	Note: Samples were picked from a block soil sample at the University of Kentucky and the sent to Lawrence Livermore National Laboratories Center for Accelerator Mass Spectrometry (LLNL CAMS) for AAA pretreatment. * Site name codes: MMRB = Mt. McKinley Restraining Bend; 01 = block sample #1; A-F = organic fractions separated from the block sample. †AMS analysis performed at LLNL CAMS. §The quoted age is in radiocarbon years using the Libby half-life of 5568 years and following the conventions of Stuiver and Polach (1977). Sample preparation backgrounds have been subtracted, based on measurements of radiocarbon-dead standards pretreated in parallel with samples. #Ages calibrated with Oxcal v4.2 (Bronk Ramsey, 2009a) using the IntCal 13 calibration curve (Reimer et al., 2013), with ages quoted at 2σ errors. ˠ Sample was large enough to take a sample specific aliquot for 13C analysis
11	** (a) black, charcoal-like spheres – possibly seeds. (b) collection of fine roots penetrating the buried soil horizon. (c) inherited charcoal preserved within the soil
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14	Unpublished radiocarbon data from a block sample collected from buried peaty soil exposed in a natural exposure near the Chedotlothna Glacier. 15-20 cm of fibrous, organic rich silt with silty sand laminae accumulated on top of a cobble-boulder glacial till. soil buried by ~1m of poorly sorted silt to coarse sand sheets that appear to blanket many of the surfaces in the area. These samples were delayed for a very long time at the lab, and samples 170562 and 170563 were run as duplicates, but reported miscommunication in the lab leads to some uncertainty about what these ages represent.
15	Sample Name	CAMS Lab Number	d13C	fraction Modern	±	D14C	±	14C Age (BP)§	±	Calibrated age (cal BP)#	Sample material**	Sampled Unit	Submitted sample mass (mg)	Interpretation	Easting	Northing	Elevation (msl)
16	MMRB hz.4*	168499	-32.57	0.7444	0.0026	-255.6	2.6	2370	30		woody macrofossils	buried soil	25.48		553056	6982875	898
17	MMRB hz.4 †	168500	-32.57	0.881	0.0032	-119	3.2	1020	30		woody macrofossils	buried soil	25.48		553056	6982875	898
18	MMRB hz.3*	168501	-28.67	0.9472	0.0027	-52.8	2.7	435	25		woody macrofossils	buried soil	105.49		553056	6982875	898
19	MMRB hz.3 dup	168502	-28.67	0.9528	0.0025	-47.2	2.5	390	25		woody macrofossils	buried soil	105.49		553056	6982875	898
20	MMRB hz.2	168503	-28	0.9571	0.0036	-42.9	3.6	350	36		woody macrofossils	buried soil	20.44		553056	6982875	898
21	MMRB hz.1 *	168505	-27.19	0.9825	0.0025	-17.5	2.5	140	25		woody macrofossils	buried soil	114.7		553056	6982875	898
22	MMRB hz.1 dup	168506	-27.19	0.9741	0.0028	-25.9	2.8	210	25		woody macrofossils	buried soil	114.7		553056	6982875	898
23	mmrb hz.1	170562	-27.19	0.9523	0.0034	-47.7	3.4	395	30		woody macrofossils	buried soil	114.7		553056	6982875	898
24	mmrb hz.1	170563	-27.19	0.9599	0.0029	-40.1	2.9	330	25		woody macrofossils	buried soil	114.7		553056	6982875	898
25															553056	6982875	898
26	1) d13C values are the assumed values according to Stuiver and Polach (Radiocarbon, v. 19, p.355, 1977) when given without decimal places. Values measured for the material itself are given with a single decimal place. Samples with an (*) were large enough, and as requested, to take a sample specific split for IRMS d13C analysis.
27	2) The quoted age is in radiocarbon years using the Libby half life of 5568 years and following the conventions of Stuiver and Polach (ibid.).
28	3) Radiocarbon concentration is given as fraction Modern, D14C, and conventional radiocarbon age.
29	4) Sample preparation backgrounds have been subtracted, based on measurements of samples of 14C-free coal. Backgrounds were scaled relative to sample size.
30	5) Note, CAMS# 168500 (†) had a significantly smaller %C (~11%) relative to all of the other samples (35-60%)
31	6) Assumed value of -28±2 for CAMS 168503 based on sample specific IRMS results.
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