Geology, permafrost forms photos

On the northern bank of Taimyr Lake, and in some other places, Cretaceous sands with great quantity of  fossilated tree residues are exposured. 
This strange object was found by us in exposures of Cretaceous sands (previous photo). Diameter is about 1 m. It is a riddle. What is it? Nobody could explain it for us.  
A typical landscape of Byrranga foothills (Olenya river)
Камень

The holy stone of nomadic dolgans at reindeer ford over Bikada river (periglacial erratic boulder).

Кам

The aged glacial stony hill (kam) – is the typical relief form of Reserve plain tundra, confined with glacial landscapes.

Underground ice-lodes on terrace near the Yamu-Tarida river mouth.
Байджарахи

Baijarakh hillocks on the river bank.

When a slope are gentled and there are no erosion, baijarakhs begin to be grown by high grass (the bank of Taimyr Lake near Yamu-Tarida river mouth)
Полигоны

A  polygonal bog (photo by M.V. Orlov).

The spotty tundra.
It is quite possible to meet desert landscape in tundra ( the river mouth of Yamu-Tarida)
Иногда на горных реках зимой остаются не полностью промерзшие участки русла. В конце концов, от высокого сжатие воды, лед над ней как бы "взырвается", и образуются такие купола
Начало ледохода на р. Бикада - первая подвижка льда