Ra isotope perspective on the hydrology and continuity of permafrost in the high Arctic.

The continuous permafrost in the valleys of Svalbard is dotted by pingos, which are small hills formed by the near surface freezing of ascending groundwater. In this study, we used H and Ra isotopes to inquire into the sub-surface residence time of groundwater discharging at these pingos. While its low H suggests that the pingo-associated groundwater is basically not modern (i.