Guégan, E.; Sinitsyn, A.; Kokin, O., and Ogorodov, S., 2016. Coastal geomorphology and ground thermal regime of the Varandey area, northern Russia.

This study documents a regional summary of the present geomorphology of the Varandey area coastline of northern Russia. Fieldwork was undertaken over three seasons (2011–2013) and combined with observations from 1999. The Varandey area has morphologies varying from low-gradient, wide sandy shores with dune belts that reflect stable and aggrading coasts (where sandy shore processes govern the coastal dynamics) to subvertical coastal ice-rich bluffs and narrow beaches, which reveal active coastal recession (where cohesive shore processes are dominant). In addition to these geomorphological observations, the study documents a continuous ground temperature recorded from July 2011 through August 2013 by six thermistor strings installed on a 500-m-long transect perpendicular to the coast. The thermal regime of the ground in permafrost areas controls its mechanical strength and stability, therefore influencing the coastal dynamics through a recession caused by a thawing bluff failure (thermodenudation). The ground temperature recorded along the transect varied from −1.9°C at the thermistor strings located 500 m from the shoreline to 0.3°C at the thermistor strings situated on the upper beach. The temperature measurements characterize this area as being affected by a warm permafrost near the temperature phase change (transient conditions), and the stability of the ice-rich segment of this coastline is sensitive to future variations of air temperature. Our investigation did not reveal permafrost underneath the upper beach of the thermally investigated section and did identify numerous cryopegs in the inland portion.