Research Article

2.8 Million Years of Arctic Climate Change from Lake El’gygytgyn, NE Russia

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Science  20 Jul 2012:
Vol. 337, Issue 6092, pp. 315-320
DOI: 10.1126/science.1222135

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  1. Fig. 1

    Location of Lake El’gygytgyn in northeastern Russia (inserted map) and schematic cross-section of the El’gygytgyn basin stratigraphy showing the location of ICDP sites 5011-1 and 5011-3. At site 5011-1, three holes (1A, 1B, and 1C) were drilled to replicate the Quaternary and uppermost Pliocene sections. Hole 1C further penetrated through the remaining lacustrine sequence down to a 318-m depth and then ~200 m into the impact rock sequence underneath. Lz1024 is a 16-m-long percussion piston core taken in 2003 that fills the stratigraphic gap between the lake sediment surface and the top of drill cores 1A and 1B.

  2. Fig. 2

    Age/depth model with resulting sedimentation rates for the ICDP 5011-1 core composite based on magnetostratigraphy and correlation between sediment proxy data, the LR04 marine isotope stack (12), and regional spring and summer insolation (13). Initial first-order tie points are indicated by black diamonds; second- and third-order tie points are denoted by the blue curve. The red star marks the time of the impact inferred from 40Ar/39Ar dating (7) at 3.58 (±0.04) Ma. Black and white bars denote normal and reversed polarity, respectively. Mass movement deposits and core gaps greater than 50 cm in thickness are indicated on the right y axis in gray and blue, respectively. mblf, meters below lake floor.

  3. Fig. 3

    (A to H) (A) LR04 global marine isotope stack (12) and (B) mean July insolation for 67.5°N (13) for the past 2.8 My compared with (C) magnetostratigraphy, (D) facies, (E) magnetic susceptibility, (F) TOC contents, (G) Mn/Fe ratios, and (H) Si/Ti ratios in the sediment record from Lake El’gygytgyn (magnetic susceptibility and x-ray fluorescence data are smoothed using a 500-year weighted running mean to improve the signal-to-noise ratio). Super interglacials at Lake El’gygytgyn are highlighted with red bars. (I to L) Expanded views into the interglacials MIS 1, 5e, 11c, and 31 and adjoining glacials/stadials. (I) Reconstructed MTWM and (J) PANN based on the pollen spectra and best modern analog approach [modern values from (56)]. (K) Mean July insolation for 67.5°N (13) compared with El’gygytgyn Si/Ti ratios, smoothed by five-point weighted running mean. (L) Tree and shrub pollen percentages compared with spruce pollen content. Simulated July surface air temperatures (red and green dots) at the location of the lake are shown for comparison. The location of the dots relative to the x axis corresponds with the GHG and orbital forcing used in each interglacial simulation (see supplementary materials). Simulated modern and preindustrial temperatures are close to observed values, so model temperatures are not corrected for bias. The green dot indicates the results derived with a deglaciated Greenland and increased heat flux under Arctic Ocean sea ice by 8 W m−2.

  4. Fig. 4

    Simulated interglacial warming (2-m surface temperature in degrees Celsius) relative to preindustrial levels. (A) MIS 1 (9-ky orbit and GHGs). (B) MIS 5e (127-ky orbit and GHGs). (C) MIS 11c (409-ky orbit, GHGs, no Greenland Ice Sheet, and 8 W m−2 enhanced oceanic heat convergence under Arctic sea ice). (D) MIS 31 (1072-ky orbit, GHGs, and no Greenland Ice Sheet). Orbital and GHG forcing for MIS 5e and 11c follow that used by Yin and Berger (40). Forcing for MIS 31 follows that used by DeConto et al. (42). The location of Lake El’gygytgyn is shown with a star near the bottom-center of each panel. Areas of no shading (white) roughly correspond to statistically insignificant anomalies at the 95% confidence interval.

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