Earth’s Cryosphere, 2021, vol. XXV, No. 3, pp. 3–18

CRYOLITHOGENESIS

NATURAL ENVIRONMENT DYNAMICS AND MORPHOLITHOGENESIS IN SHALLOWS OF THE EAST SIBERIAN ARCTIC SHELF

A.V. Gavrilov, E.I. Pizhankova

Lomonosov Moscow State University, Faculty of Geology, Leninskie Gory, 1, Moscow, 119991, Russia;
gavrilov37@bk.ru, epijankova@mail.ru

The shallows of the Laptev and East Siberian seas formed on the site of islands composed of the sediments of the Late Pleistocene Ice Complex which eroded in the 17th–20th centuries and are linked to positive morphostructures. The present article considers factors of modern sedimentation in marine shallows with the formation of islands (Yaya, Nanosny, Zatoplyaemyy, Leykina, etc.). Among these factors are a decrease in sea ice extent, an increase in the duration of the ice-free period, and the activation of destructive cryogenic processes triggered by the current climate warming. A decrease in ice coverage led to the dominance of hydrodynamic processes in sedimentation, unlike the primary role of sea ice in this process in the 17th–19th centuries. Sediment deficit in these centuries is substituted by its excess owing to the activation of cryogenic processes at the turn of the 20th and 21st centuries. As a result, the erosional shoreface profile is transforming into an accumulative one. Sedimentation is occurring parallel to a rising sea level related to a warming climate. A rise in the surface of islands and sandbanks is recorded on satellite images where there are modern positive vertical movements. The formation of islands and sandbanks is accompanied by their syngenetic freezing.

Key words: morpholithogenesis, sedimentation, morphostructures, modern climate warming, remote sensing data, marine shallows