Research Article

Ice Age Terminations

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Science  09 Oct 2009:
Vol. 326, Issue 5950, pp. 248-252
DOI: 10.1126/science.1177840

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  1. Fig. 1

    The δ18O time series showing the abrupt shift in the AM during T-II, as recorded in Sanbao Cave. This feature was previously observed in Dongge Cave (9) and Hulu Cave (6), as well as Sanbao Cave (11); however, the new dating methods applied here constrain the age of this feature to lie within a century of 129.0 ky B.P. This date agrees with previous dates; however, the errors reported here are about an order of magnitude smaller than those reported in the earlier studies.

  2. Fig. 2

    The δ18O time series over the past four glacial terminations from (A) Hulu and Dongge caves (7, 10), (B) Sanbao Cave [light green (11) and dark green SB25 (this study)], and (C and D) Sanbao Cave [sample SB61 (this study)]. Error bars indicate 230Th dates and 2σ errors. δ18O increases downward. 21 July insolation at 65°N (29) is in gray. Light green bars depict the WMIs. Similarities between T-I and T-III and between T-II and T-IV are apparent. Analogous to the MI, BA (yellow bar), and YD events during T-I, we identify similar events during T-III: MI-III, BA-III (yellow bar), and YD-III. The light green bars WMI-Ia and WMI-Ib (YD); WMI-II, WMI-IIIa, and WMI-IIIb (YD-III); and WMI-IV indicate WMIs.

  3. Fig. 3

    Events during (A) T- II, (B) T-III, and (C) T-IV. (i) Sanbao δ18O, colors and sources as in Fig. 2. Light green bars indicate WMIs; yellow bars indicate the YD-III and BA-III/ACR-III. 21 July insolation at 65°N is plotted in gray (29). Antarctic records of (ii) CH4 (36), (iii) δD [dark blue, Vostok (36), light blue EPICA/Dome C (39)], (iv) CO2 (36), (v) dust (36), (vi) δ18O of O2 (36), and (vii) Vostok temperature deviation (40). North Atlantic sediment (ODP 980) records (8) of (viii) IRD and (ix) benthic δ18O are also shown. All records are plotted on their original time scales but shifted so that the abrupt methane shifts correlate with the abrupt cave δ18O shifts and the marine IRD peaks correlate with the high-δ18O cave excursions. The Antarctic records with O2/N2 chronologies were shifted no more than 2.2 ky, within quoted errors.

  4. Fig. 4

    (A) Obliquity (29) and (B) 21 July insolation at 65°N (29). Black bars highlight the highest and lowest insolation value bounding each major termination. (C) Rate of change of 21 July insolation at 65°N (29). Red shading indicates the timing of the WMIs. The yellow dashed line indicates the lowest maximum for the four terminations. (D) δ18O from Hulu (purple) (7), Dongge Caves (dark blue) (10), Sanbao Cave [light green (11), dark green (this study)], and Linzhu Cave [yellow-green (this study)]. (E) Vostok CO2 record (36) on a time scale created by interpolating linearly between methane-cave correlation points on each of the four terminations and T-IIIA. (F) Benthic δ18O values for ODP 980 (8) on a time scale created by interpolating linearly between IRD-cave correlation points on each of the four terminations and T-IIIA. Light green and yellow vertical bars are the same as in Fig. 2.

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