Fig. 6: Development of fold amplitudes.
From: Shear margins in upper half of Northeast Greenland Ice Stream were established two millennia ago
a–c Conceptual sketches for the effect of folding on layer disturbance and development of fold amplitudes (1–3) as a function of depth. d Part of radargram shown in Fig. 2 with traced layers and respective folds. Shown are the uppermost 1400 m with y-axes ticks spaced 200 m. Numbers on the left show amplitudes and the corresponding reference depth for 3 examples (subscript indicates age of layer), green/red vertical lines on the left indicate the position of the fold hinges of the anti- and synclines. Red vertical line on right indicates the location of the East Greenland Ice core Project (EGRIP) core with each reference layer annotated with its age; in years BP. e Distribution of amplitudes of fold limb C1. The top panel shows amplitude as a function of depth and the bottom amplitude as a function of age The yellow dots indicate the data points derived from the radar layers. Red arrows indicate data points of example folds picked in d. The black and blue lines indicate the trend with a clear kink around 300 m depth or 2000 years of age.
