Poster №5 – The history of the relief formation of the area
@kizhi
The Island of Kizhi is an esker (a bed of a former stream in the body of the glacier filled with boulders, gravel and sand).
Huge blocks of ice could be buried under a thick layer of debris. When they melted soft ceilings of these underground caves could collapse resulting in deep thermokarst sinkholes. There are several of them in Kizhi and one of them is just in front of you.
When Zaonezhie peninsula was freed of ice pressure there were several earthquakes measuring above 8 on the Richter scale. Sometimes earthquakes caused landslides. Their consequence as an earth creep terrace can be observed on the Island of Kizhi to the west of the windmill from the village of Vorony Ostrov.
The deglaciation resulted in a huge and cold lake. The level of the lake was 95–100 meters higher of the present one. The greatest part of the Zaonezhie peninsula including the system of Kizhi Islands was under water of this lake. Gradually the water level became lower. The first tiny island emerged above the surface of the water 7,140–6,500 years ago. It was the highest point of the present Kizhi Island called Naryina Hill. A chain of six little islands appeared the same way 4,200–3,150 years ago.
They merged into one just in the Subatlantic period, that is 2,500–2,100 years ago. That is how the Island of Kizhi was formed. The eastern shore of the island is steeper than the western one. This is the result of the dramatic action of the breaking waves from the east. One can see gently sloping shore terraces made by smoothed boulders. Nowadays, the system of numerous islands in the southern part of Zaonezhie is called Kizhi skerries. Bolshoy Klimenetsky is the biggest island in the skerries. Its length is 28 km, the width of the island ranges from 4 to 8 km.[текст с сайта музея-заповедника "Кижи": http://kizhi.karelia.ru]
The composition of glacial deposits of the Kizhi Island is diverse. One can find granite, limestone, dolomite, quartz, silicon, siltstone and other minerals on the shore of the island. But shunghite-bearing rocks prevail. Local soil has high limestone content that neutralizes natural acidity and provides favorable conditions for vegetation development. The varying relief of the site provides various moistening and light conditions. That results in a surprising diversity of the plant kingdom of the island.
What plant species can one see on the island? For this information see poster №6.
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