Uzon Volcano Caldera

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The caldera (from the Spanish for bowl or kettle) is a bowl-shaped basin, 9×12 km in size. The highest point of the caldera wall is Barany (Ram) Peak, 1,617 m above sea level, while the lowest point is 650–700 m. The caldera was formed about 40,000 years ago.

The first researcher to visit the caldera was geologist K. von Ditmar in 1854. The first studies were conducted in 1933 by B.I. Piip.

The unique phenomenon of the Uzon Caldera, like a natural laboratory, provides a live demonstration of thermal ecosystem processes. The hydrothermal system of the Uzon is one of the most powerful in Kamchatka. Over 1,000 hot springs of differing size and shape, numerous vapor-gas springs, mud caldrons, small volcanoes, and a number of thermal lakes are concentrated within a narrow 200–350 meter-wide strip on five thermal fields. There are even a few “Narzan” (mineral) springs.

Here one can observe, unlike anywhere else on Earth, a variety of processes involved in the creation of volcanoes, products of the glacial period, and fields with virgin sulfur beds and colorful rock formations created by hydrothermal forces.

Rocks formed by hydrothermal processes have a distinct vertical zonality as, with changes in temperature and pressure from deeper layers, chemicals settle out first for which the crystallization temperature is relatively high. Later settle chemicals with lower crystallization temperatures. Thus, the vertical profile of rock beds can be likened to a stack, where each chemical compound has its own “shelf,” distinctly formed under the conditions at the time of its deposit.

The unique Bannoye (Sauna) Lake is found here, with its radon upwelling. A sulfur cork located at the bottom of the 28-meter deep lake plugs a reservoir of molten sulfur beneath.

Even today, arsenic, antimony, and mercury sulfide ores continue to form and even oil, with a series of distinct characteristics, has been observed seeping to the surface.

Sixty-five different hydrothermal minerals have been discovered in Uzon, making up an exceptional mineral palette. In the mid-1980s, V.I. Popova et al. described for the first time in the USSR two original forms of arsenic sulfide: uzonite and alakranite. Uzonite is not found anywhere in the world except in the caldera.

Another peculiarity of Uzon’s thermal fields is oil — the high optical activity of which proves that it is biogenic in nature (i.e., a substance produced by life processes).

The uniqueness of Uzon Caldera’s natural ecosystems is in the variety of its components, their unusual combination, in the role of nutrients, and in the cycling of matter. Arboreal vegetation is found adjacent to mountain vegetation and alpine meadows. Nesting birds are found here in abundance. Animals and plants have found ways to adapt to the thermal environment.
Finally, a variety of heat-loving microorganisms adapted to the extreme conditions have evolved here with very distinct characteristics. This is one of the most interesting areas of future biotechnological research.

The Uzon Caldera could be a microbiogeochemical refuge for the conservation and natural reproduction of microbial genetic resources for science in the 21st century.

In 2008, following a long slumber, a geyser began to erupt in Uzon, increasing its attractiveness to visitors.

Uzon is beautiful at any time of the year and in any weather, but the colors of sunny September are so striking, they evoke genuine awe in visitors.

Did You Know

The Semyachicksky estuary is counted as one of the most important wetlands as a key ornithological territory, protected by the Ramsar Convention.