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Figure 2 | Reconstructed records from the NEEM ice core. The reconstructed records of 5'°Oj-¢, 5'8Oaum (reversed scale) CHy, N>O, 8'°N and air content (reversed scale) on the EDMLI timescale’*. Zone 1 (cyan) is seen to contain a fold while zone 2 (green) and zone 3 (orange) are reversed and cover identical time periods. NGRIP records (light grey) and EDML records (dark grey) are included where they are available. The CHy, N2O and air content records contain spikes from 127 to 118.3 kyr (shaded grey).

Figure 2 | Reconstructed records from the NEEM ice core. The reconstructed records of 5'°Oj-¢, 5'8Oaum (reversed scale) CHy, N>O, 8'°N and air content (reversed scale) on the EDMLI timescale’*. Zone 1 (cyan) is seen to contain a fold while zone 2 (green) and zone 3 (orange) are reversed and cover identical time periods. NGRIP records (light grey) and EDML records (dark grey) are included where they are available. The CHy, N2O and air content records contain spikes from 127 to 118.3 kyr (shaded grey).

Related Figures (3)

Figure 1 | Observed NEEM records. a, A surface elevation map (scale to the right) of the position of the NEEM camp, including coloured upstream depositional positions (upstream time marker scale below) of the ice found in the NEEM ice core. The deep ice-core sites NGRIP, NEEM and Camp Century and the tracks of the RES images shown in Fig. 3f and g (red lines) are shown on the map. b, The observed records of 5'°O,.., 5'"Oatm (reversed scale) CHy, N30, 5N and air content (reversed scale) from 2,162 m and deeper are plotted on the NEEM depth scale (bottom x axis). The air content measurements from LGGE and from University of Bern (thin curve, small symbols) are both included. Zones 0-6 (blue, 0-2,206.5 m; cyan, 2,206.5-2,209.6 m; green, 2,209.6-2,262.2 m; orange, 2,262.2-2,364.5 m; red, 2,364.5-2,418.0 m; dark red, 2,418.0-2,432.2 m; and brown, 2,432.2-2,537 m) represent the sections of the NEEM ice-core records with symbols marking the start (diamond) and end (square) of each zone. There is no discontinuity between zones 4 and 5 but spikes of CH,, N2O and air content occur in zone 4 (shaded grey). For comparison, the NGRIP data are plotted as light grey curves on the NGRIP depth scale on top of the plot. The NEEM and NGRIP depth scale are synchronized between 2,162 and 2.207.6 m NEEM depths.
Figure 1 | Observed NEEM records. a, A surface elevation map (scale to the right) of the position of the NEEM camp, including coloured upstream depositional positions (upstream time marker scale below) of the ice found in the NEEM ice core. The deep ice-core sites NGRIP, NEEM and Camp Century and the tracks of the RES images shown in Fig. 3f and g (red lines) are shown on the map. b, The observed records of 5'°O,.., 5'"Oatm (reversed scale) CHy, N30, 5N and air content (reversed scale) from 2,162 m and deeper are plotted on the NEEM depth scale (bottom x axis). The air content measurements from LGGE and from University of Bern (thin curve, small symbols) are both included. Zones 0-6 (blue, 0-2,206.5 m; cyan, 2,206.5-2,209.6 m; green, 2,209.6-2,262.2 m; orange, 2,262.2-2,364.5 m; red, 2,364.5-2,418.0 m; dark red, 2,418.0-2,432.2 m; and brown, 2,432.2-2,537 m) represent the sections of the NEEM ice-core records with symbols marking the start (diamond) and end (square) of each zone. There is no discontinuity between zones 4 and 5 but spikes of CH,, N2O and air content occur in zone 4 (shaded grey). For comparison, the NGRIP data are plotted as light grey curves on the NGRIP depth scale on top of the plot. The NEEM and NGRIP depth scale are synchronized between 2,162 and 2.207.6 m NEEM depths.
Figure 3 | Disturbances of the deep NEEM ice. a, The reconstructed NEEM water stable isotope record (black curve) including NGRIP data between 114- 108 kyr BP (grey) on the EDML] timescale that has been colour coded according to age. Below 2,432.19 m (grey shading) no dating has been attempted. b, The colour-coded data plotted with the original data on the NEEM depth scale visualizing the discontinuities and the reversed sections. c, d, c-Axis orientations on Schmidt diagrams for depths 2,203 m, 2,308 m and 2,395 m (c) and polarized light pictures of ice thin sections from the same three depths (d) demonstrate the very different ice rheology of the glacial and interglacial ice, leading to different flow properties. e, Cartoon of a possible history of the formation of two overturned folds at NEEM inspired by the observed undulations in the RES images (f and g). f, g, Center for Remote Sensing of Ice Sheets (CReSIS) ice-penetrating RES images from NASA Operation IceBridge campaign 2011. f, A 52-km-long line to the west that illustrates that overturning folds do occur (MCORDS: 20110329_02_020); g, a 48-km-long line crossing the deep drill site (MCORDS 20110329_02_028). The NEEM site is marked on the image, and two dated horizons are marked. More details can be found in Supplementary Information.
Figure 3 | Disturbances of the deep NEEM ice. a, The reconstructed NEEM water stable isotope record (black curve) including NGRIP data between 114- 108 kyr BP (grey) on the EDML] timescale that has been colour coded according to age. Below 2,432.19 m (grey shading) no dating has been attempted. b, The colour-coded data plotted with the original data on the NEEM depth scale visualizing the discontinuities and the reversed sections. c, d, c-Axis orientations on Schmidt diagrams for depths 2,203 m, 2,308 m and 2,395 m (c) and polarized light pictures of ice thin sections from the same three depths (d) demonstrate the very different ice rheology of the glacial and interglacial ice, leading to different flow properties. e, Cartoon of a possible history of the formation of two overturned folds at NEEM inspired by the observed undulations in the RES images (f and g). f, g, Center for Remote Sensing of Ice Sheets (CReSIS) ice-penetrating RES images from NASA Operation IceBridge campaign 2011. f, A 52-km-long line to the west that illustrates that overturning folds do occur (MCORDS: 20110329_02_020); g, a 48-km-long line crossing the deep drill site (MCORDS 20110329_02_028). The NEEM site is marked on the image, and two dated horizons are marked. More details can be found in Supplementary Information.
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GlaciologyClimate ChangeIce Core PaleoclimatologyIces Cores
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