Dzau is a volcanic centre in
Georgia (country)
Georgia (, ; ) is a transcontinental country at the intersection of Eastern Europe and Western Asia. It is part of the Caucasus region, bounded by the Black Sea to the west, by Russia to the north and northeast, by Turkey to the southwest ...
,
Russian-occupied de facto
South Ossetia
South Ossetia, ka, სამხრეთი ოსეთი, ( , ), officially the Republic of South Ossetia – the State of Alania, is a partially recognised landlocked state in the South Caucasus. It has an officially stated populat ...
. It is also known as Java volcanic centre. The field is close to the town of
Dzau
Java ( ka, ჯავა ; os, Дзау, ''Dzaw''; russian: Джава ''Dzhava'') is a town of approximately 1,500 people in Georgia (in South Ossetia). According to Georgia's current official administrative division, Java is a main town of Java ...
, in the
Greater Liakhvi River
The Great Liakhvi ( ''Didi Liakhvi'', , ''Styr Lewakhi'') is a river in central Georgia, which rises on the southern slopes of the Greater Caucasus Mountain Range in the de facto independent region of South Ossetia and flows into the Kura (Mtk ...
valley.
The
Caucasus
The Caucasus () or Caucasia (), is a region between the Black Sea and the Caspian Sea, mainly comprising Armenia, Azerbaijan, Georgia, and parts of Southern Russia. The Caucasus Mountains, including the Greater Caucasus range, have historically ...
has been affected by volcanic activity during the Late
Cenozoic
The Cenozoic ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterised by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configura ...
in three areas. One of these is the Kazbek area with the
Kazbek
Mount Kazbek or Mount Kazbegi is a dormant stratovolcano and one of the major mountains of the Caucasus, located on the Russian-Georgian border - in Russia's North Ossetia region and Georgia's Kazbegi District.
At 5,034 m (16,515 ft) high, i ...
,
Keli Highland and Dzau systems which were active during the
Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ...
.
It contains three volcanoes, Tsru () also known as Chvriva at altitude, Sazeleti () at altitude and Bordzhnis or Borgnisi () at altitude. Sazeleti is a lava cone, the other two volcanoes are
fissure vent
A fissure vent, also known as a volcanic fissure, eruption fissure or simply a fissure, is a linear volcanic vent through which lava erupts, usually without any explosive eruption, explosive activity. The vent is often a few metres wide an ...
s. Remnants of lava flows have also been found.
The volcanic field has erupted principally
andesite
Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomi ...
. Minerals found in the rocks include
amphibole
Amphibole () is a group of inosilicate minerals, forming prism or needlelike crystals, composed of double chain tetrahedra, linked at the vertices and generally containing ions of iron and/or magnesium in their structures. Its IMA symbol is A ...
,
clinopyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...
,
orthopyroxene
The pyroxenes (commonly abbreviated to ''Px'') are a group of important rock-forming inosilicate minerals found in many igneous and metamorphic rocks. Pyroxenes have the general formula , where X represents calcium (Ca), sodium (Na), iron (Fe II) ...
and
plagioclase
Plagioclase is a series of tectosilicate (framework silicate) minerals within the feldspar group. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a continuous solid solution series, more prope ...
.
The volcanoes are possibly between 200,000 and 100,000 years old.
References
Sources
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External links
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Volcanoes of Georgia (country)
Volcanic fields
Pleistocene volcanoes
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