Yana River Mouth
Yana River Mouth – has the area of about 6,600 km2. Its top lies in the place where a small-arm samogon shoots off at the distance of 140 m from the estuarial range of the main arm – Glavnoe Ruslo (meaning “Main Riverbed”). Seventeen kilometers up the top, there is an outlet of the Yana – a polar station Yubileynaya. The river mouth is limited from the west and the south by 30–60 m drops of yedoma and from the east by the Kargin terrace. The mouth is a vast waterlogged zone. Tundra landscapes are typical of the Yana mouth. The ancient marine terrace and the high deltaic alluvial plain possess polygonal ridge microrelief so characteristic of the tundra. The layer of seasonal deforestation is 0.6–0.8 m. The delta is cut by two major and many minor arms. The marine edge of the mouth is fringed by an offshore bar which is overlaid in the arm mouths. In the mouths of both the major arms, there form stream-mouth bars cut by channels. Permafrost is widespread, not only at the mouth but in the seashore near the mouth as well.
The delta is formed mainly by marginal marine deposits forming series of offshore bars; river sediments are only spread in relatively narrow stripes along the arms. On the mouth surface, there are numerous thermokarst lakes which form due to ice melt outs in the estuary permafrost. Negative and positive water surges play a significant role in the YRE formation. Wind foreshores are developing all around the estuary.