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Dzau (volcano)
Dzau is a volcanic centre in Georgia (country), Russian-occupied de facto South Ossetia. It is also known as Java volcanic centre. The field is close to the town of Dzau, in the Greater Liakhvi River valley. The Caucasus has been affected by volcanic activity during the Late Cenozoic in three areas. One of these is the Kazbek area with the Kazbek, Keli Highland and Dzau systems which were active during the Quaternary. 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 vents. Remnants of lava flows have also been found. The volcanic field has erupted principally andesite. Minerals found in the rocks include amphibole, clinopyroxene, orthopyroxene 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 chemi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shida Kartli
Shida Kartli ( ka, შიდა ქართლი, , ; "Inner Kartli") is a landlocked administrative region (''Mkhare'') in eastern Georgia. It comprises a central part of the historical-geographic province of Shida Kartli. With an area of , Shida Kartli is the 8th largest Georgian region by land area. With 284,081 inhabitants, it is Georgia's seventh-most-populous region. Shida Kartli's capital and largest city, Gori, is the 5th largest city in Georgia. The region is bordered by the Russian Federation to the north, Georgian regions of Mtskheta-Mtianeti to the east, Kvemo Kartli to the south, Samtskhe-Javakheti to the southwest, Imereti to the west, and Racha-Lechkhumi and Kvemo Svaneti to the northwest. It consists of the following municipalities: Gori, Kaspi, Kareli, Java, Khashuri. The northern part of the region, namely Java, and northern territories of Kareli and Gori municipalities (total area of 1,393 km²), have been controlled by the authorities of the self- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today, although a third epoch, the Anthropocene, has been proposed but is not yet officially recognised by the ICS). The Quaternary Period is typically defined by the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four successive formations or "orders" ( it, quattro ordini). The term "quaternary" was introduced by Jules Desnoye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanoes Of Georgia (country)
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 properly known as the plagioclase feldspar series. This was first shown by the German mineralogist Johann Friedrich Christian Hessel (1796–1872) in 1826. The series ranges from albite to anorthite endmembers (with respective compositions NaAlSi3O8 to CaAl2Si2O8), where sodium and calcium atoms can substitute for each other in the mineral's crystal lattice structure. Plagioclase in hand samples is often identified by its polysynthetic crystal twinning or 'record-groove' effect. Plagioclase is a major constituent mineral in the Earth's crust, and is consequently an important diagnostic tool in petrology for identifying the composition, origin and evolution of igneous rocks. Plagioclase is also a major constituent of rock in the highlan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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) or magnesium (Mg) and more rarely zinc, manganese or lithium, and Y represents ions of smaller size, such as chromium (Cr), aluminium (Al), magnesium (Mg), cobalt (Co), manganese (Mn), scandium (Sc), titanium (Ti), vanadium (V) or even iron (Fe II) or (Fe III). Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that crystallize in the orthorhombic system are known as orthopyroxenes. The name ''pyroxene'' is derived from the Ancient Greek words for 'fire' ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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) or magnesium (Mg) and more rarely zinc, manganese or lithium, and Y represents ions of smaller size, such as chromium (Cr), aluminium (Al), magnesium (Mg), cobalt (Co), manganese (Mn), scandium (Sc), titanium (Ti), vanadium (V) or even iron (Fe II) or (Fe III). Although aluminium substitutes extensively for silicon in silicates such as feldspars and amphiboles, the substitution occurs only to a limited extent in most pyroxenes. They share a common structure consisting of single chains of silica tetrahedra. Pyroxenes that crystallize in the monoclinic system are known as clinopyroxenes and those that crystallize in the orthorhombic system are known as orthopyroxenes. The name ''pyroxene'' is derived from the Ancient Greek words for 'fire' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Amp. Amphiboles can be green, black, colorless, white, yellow, blue, or brown. The International Mineralogical Association currently classifies amphiboles as a mineral supergroup, within which are two groups and several subgroups. Mineralogy Amphiboles crystallize into two crystal systems, monoclinic and orthorhombic. In chemical composition and general characteristics they are similar to the pyroxenes. The chief differences from pyroxenes are that (i) amphiboles contain essential hydroxyl (OH) or halogen (F, Cl) and (ii) the basic structure is a double chain of tetrahedra (as opposed to the single chain structure of pyroxene). Most apparent, in hand specimens, is that amphiboles form oblique cleavage planes (at around 120 degrees), whe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 predominantly of sodium-rich plagioclase plus pyroxene or hornblende. Andesite is the extrusive equivalent of plutonic diorite. Characteristic of subduction zones, andesite represents the dominant rock type in island arcs. The average composition of the continental crust is andesitic. Along with basalts, andesites are a component of the Martian crust. The name ''andesite'' is derived from the Andes mountain range, where this rock type is found in abundance. It was first applied by Christian Leopold von Buch in 1826. Description Andesite is an aphanitic (fine-grained) igneous rock that is intermediate in its content of silica and low in alkali metals. It has less than 20% quartz and 10% feldspathoid by volume, with at least 65% of the fe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 and may be many kilometres long. Fissure vents can cause large flood basalts which run first in lava channels and later in lava tubes. After some time, the eruption tends to become focused at one or more spatter cones. Small fissure vents may not be easily discernible from the air, but the crater rows (see Laki) or the canyons (see Eldgjá) built up by some of them are. The Dike_(geology)#Magmatic_dikes, dikes that feed fissures reach the surface from depths of a few kilometers and connect them to deeper magma chamber, magma reservoirs, often under volcanic centers. Fissures are usually found in or along rifts and rift zones, such as Iceland and the East African Rift. Fissure vents are often part of the structure of shield volcanoes. Icelan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keli Highland
The Keli (Qeli) Highland ( ka, ყელის ზეგანი, ''qelis zegani'') is a volcanic field in Georgia on the western side of the Jvari Pass south to the Greater Caucasus range. More than thirty volcanic edifices on an area of 20x30km2 make up this volcanic field, which consists mostly of monogenetic volcanic structures. The lavas are rhyolites, trachyandesites and andesites. The rivers Tetri Aragvi, Patara Liakhvi, Ksani and Didi Liakhvi originate from the Keli volcanic area, and some peaks drain into the Terek river. Several mountain ranges separate the area into distinct high plains. Quaternary Dacite lava flows overlie thich Mesozoic sedimentary sequences. Western Khorisar (elevation 3736 m) and Didi-Nepiskalo (3694 m) are the highest summits close to the crest of the Greater Caucasus. In the northeastern part of the system are the Nepiskalo volcanoes and several smaller structures. The Patara-Nepiskalo volcano is strongly degraded by glacial action and may ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, by Armenia to the south, and by Azerbaijan to the southeast. The country covers an area of , and has a population of 3.7 million people. Tbilisi is its capital as well as its largest city, home to roughly a third of the Georgian population. During the classical era, several independent kingdoms became established in what is now Georgia, such as Colchis and Iberia. In the early 4th century, ethnic Georgians officially adopted Christianity, which contributed to the spiritual and political unification of the early Georgian states. In the Middle Ages, the unified Kingdom of Georgia emerged and reached its Golden Age during the reign of King David IV and Queen Tamar in the 12th and early 13th centuries. Thereafter, the kingdom decl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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, it is one of the highest peaks in Russia and the third-highest peak in Georgia (after Mount Shkhara and Janga). Kazbegi is also the second-highest volcanic summit in the Caucasus, after Mount Elbrus. The summit lies directly to the west of the town of Stepantsminda and is the most prominent geographic feature of the area. The name Kazbeg is disputed; some claims are it is named after a Circassian nobleman who lived on it, other claims are it is named after local nobleman Dimitri Chopikashvili (grand father of the Georgian writer Aleksandre Kazbegi) got the title of "Kazgeb" from Georgian king Erekle II. The word "Kazbek" means a "nobleman" in Kabardian language. The title appeared under Georgian king Rostom in the 17th century. The name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
