Table S1.

Geochemical data (averages of replicates)

Depth (m)	δO2/N2 (‰)	δAr/N2 (‰)	δ15N2 (‰)	CH4 (ppb)	δ18Oatm (‰)	δ18Oatm st dev	δ18Oice (‰)	TAC (scc/kg)	Age (ka)	Alt. Age (ka)
2,761.19	−14.85	−2.05	0.46	665.3	0.43	0.019	−35.82	88.4	∼106	—
2,771.87	−14.22	−2.92	0.29	583.2	0.56	0.024	−35.76	94.5	115.4	-
2,801.16	−20.64	−2.17	0.45	662.3	0.54	0.049	−35.89	87.7	∼106
2,815.85	−20.14	−2.85	0.44	662.3	0.52	0.010	−36.42	87.7	∼106
2,841.85	−16.87	−4.48	0.31	669.6	0.14	0.059	−33.07	93.0	119.1	—
2,845.85	−10.18	−0.99	0.28	674.8	−0.23	0.084	−31.56	91.5	121.5	—
2,854.95	−12.08	−0.13	0.31	698.4	−0.27	0.024	−32.21	85.4	122.5	124.9
2,860.95	−16.09	−4.18	0.31	725.8	−0.28	0.024	−31.89	82.8	124.6	—
2,883.05	−17.49	−2.02	0.31	720.8	−0.07	0.000	−32.34	83.1	126.6	—
2,886.95	−15.67	−4.04	0.29	699.2	−0.17	0.010	−33.33	91.1	121.1	—
2,890.95	−17.24	−3.09	0.39	643.9	0.18	0.021	−33.44	85.8	118.9	—
2,894.05	−14.00	−2.33	0.38	560.1	0.40	0.064	−37.17	88.7	—	—
2,921.85	−15.94	−1.92	0.39	723.3	0.29	0.057	−35.24	83.8	127.6	-
2,949.05	−15.96	−2.89	0.32	717.2	−0.02	0.104	−33.39	83.2	126.7	-
2,952.85	−17.06	−4.57	0.33	651.4	0.18	0.003	−33.22	95.4	118.6	-
2,955.85	−16.38	−3.88	0.33	702.3	−0.25	0.003	−32.17	83.1	121.8	125.3
2,957.85	−14.49	−0.60	0.41	601.7	0.24	0.074	−35.54	86.1	—	—
2,959.05	−17.65	−4.26	0.33	719.6	0.12	0.064	−34.79	82.3	127.0	—
2,962.95	−14.44	−2.84	0.37	722.8	0.03	0.023	−34.28	80.2	126.8	—
2,969.05	−18.93	−4.64	0.33	663.1	−0.17	0.020	−34.08	90.2	—	—
2,975.84	−16.51	−3.31	0.33	659.9	0.13	0.043	−32.57	92.3	119.1	—
2,977.85	−15.01	−4.82	0.32	645.0	0.17	0.007	−33.05	91.2	119.0	—
2,978.05	−19.01	−5.66	0.30	672.8	−0.11	0.045	−31.82	89.4	120.6	—
2,982.14	−20.32	−2.28	0.33	652.7	0.14	0.004	−32.10	91.9	119.0	—
2,986.95	−12.85	−1.90	0.32	665.8	−0.04	0.054	−31.89	91.3	120.0	—
2,987.85	−15.85	−3.11	0.30	661.2	0.07	0.051	−32.60	91.0	119.3	—
2,990.95	−19.15	−3.90	0.33	684.3	0.03	0.081	−32.34	90.1	119.6	—
2,991.85	−18.25	−5.70	0.29	675.4	−0.17	0.035	−32.23	90.6	121.1	—
2,992.95	−12.69	−2.28	0.33	699.9	−0.11	0.014	−31.88	91.7	120.6	—
2,993.85	−12.03	−2.35	0.29	665.3	0.11	0.034	−33.17	92.9	119.2	—
2,994.95	−12.43	−2.88	0.30	659.9	−0.01	0.032	−31.94	91.4	119.8	—
2,996.85	−18.72	−6.23	0.27	643.9	−0.01	0.033	−32.86	91.4	—	—
2,997.90	−14.50	−2.41	0.32	693.2	−0.13	0.101	−31.56	91.3	120.7	—
3,000.93	−15.04	−4.53	0.29	649.8	0.06	0.016	−32.17	90.3	119.3	—
3,001.85	−15.61	−2.61	0.34	696.4	−0.12	0.042	−31.59	92.1	120.7	—
3,004.27	1.32	1.14	0.34	708.6	0.33	0.022	−33.96	87.2	>220	127.7
3,009.85	−13.03	−1.95	0.32	655.6	0.43	0.066	−34.53	89.6	>220	—
3,011.85	−7.62	0.15	0.35	575.4	0.32	0.035	−36.43	86.4	>220	—
3,019.05	−9.81	−2.37	0.31	633.7	0.31	0.069	−35.29	87.5	—	—
3,021.29	−21.19	−0.75	0.44	654.7	0.51	0.089	−36.19	86.3	>220	—
3,023.85	−9.06	−1.28	0.37	681.8	0.51	0.042	−35.20	86.8	>220	—
3,024.95	−2.19	1.50	0.31	690.4	0.30	0.081	−34.19	85.5	>220	—
3,026.05	−4.21	0.07	0.34	691.2	0.32	0.055	−33.94	85.2	>220	—
3,031.20	—	—	—	7,705.5	—	—	—	—	—	—
3,032.93	—	—	—	980.2	—	—	—	—	—	—
3,034.07	—	—	—	844.7	—	—	—	—	—	—
3,036.46	—	—	—	756.8	—	—	—	—	—	—
3,037.85	—	—	—	1,511.4	—	—	—	—	—	—

Lines in bold type are the 28 new samples used in this study. Dashes in the place of numbers mean that no data are available, or that age values cannot be calculated. scc, standard cubic centimeters.