Volcanic gasVolcanic gases are gases given off by active (or, at times, by dormant) volcanoes. These include gases trapped in cavities (vesicles) in volcanic rocks, dissolved or dissociated gases in magma and lava, or gases emanating from lava, from volcanic craters or vents. Volcanic gases can also be emitted through groundwater heated by volcanic action. The sources of volcanic gases on Earth include: primordial and recycled constituents from the Earth's mantle, assimilated constituents from the Earth's crust, groundwater and the Earth's atmosphere.
Sill (geology)In geology, a sill is a tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock. A sill is a concordant intrusive sheet, meaning that it does not cut across preexisting rock beds. Stacking of sills builds a sill complex and a large magma chamber at high magma flux. In contrast, a dike is a discordant intrusive sheet, which does cut across older rocks.
Dimension stoneDimension stone is natural stone or rock that has been selected and finished (e.g., trimmed, cut, drilled or ground) to specific sizes or shapes. Color, texture and pattern, and surface finish of the stone are also normal requirements. Another important selection criterion is durability: the time measure of the ability of dimension stone to endure and to maintain its essential and distinctive characteristics of strength, resistance to decay, and appearance.
PalagonitePalagonite is an alteration product from the interaction of water with volcanic glass of chemical composition similar to basalt. Palagonite can also result from the interaction between water and basalt melt. The water flashes to steam on contact with the hot lava and the small fragments of lava react with the steam to form the light-colored palagonite tuff cones common in areas of basaltic eruptions in contact with water. An example is found in the pyroclastic cones of the Galapagos Islands.
GyumriGyumri (Գյումրի, ɡjumˈɾi) is an urban municipal community and the second-largest city in Armenia, serving as the administrative center of Shirak Province in the northwestern part of the country. By the end of the 19th century, when the city was known as Alexandropol, it became the largest city of Russian-ruled Eastern Armenia with a population above that of Yerevan. The city became renowned as a cultural hub, while also carrying significance as a major center of Russian troops during Russo-Turkish wars of the 19th century.
WesterwaldThe Westerwald (ˈvɛstɐvalt; literally 'Western forest') is a low mountain range on the right bank of the river Rhine in the German federal states of Rhineland-Palatinate, Hesse and North Rhine-Westphalia. It is a part of the Rhenish Massif (Rheinisches Schiefergebirge or Rhenish Slate Mountains). Its highest elevation, at 657 m above sea level, is the Fuchskaute in the High Westerwald. Tourist attractions include the Dornburg (394 metres), site of some Celtic ruins from La Tène times (5th to 1st century BC), found in the community of the same name, and Limburg an der Lahn, a town with a mediaeval centre.
Phreatomagmatic eruptionPhreatomagmatic eruptions are volcanic eruptions resulting from interaction between magma and water. They differ from exclusively magmatic eruptions and phreatic eruptions. Unlike phreatic eruptions, the products of phreatomagmatic eruptions contain juvenile (magmatic) clasts. It is common for a large explosive eruption to have magmatic and phreatomagmatic components. Several competing theories exist as to the exact mechanism of ash formation. The most common is the theory of explosive thermal contraction of particles under rapid cooling from contact with water.
AniAni (Անի; Ἄνιον, Ánion; Abnicum; Ani) is a ruined medieval Armenian city now situated in Turkey's province of Kars, next to the closed border with Armenia. Between 961 and 1045, it was the capital of the Bagratid Armenian kingdom that covered much of present-day Armenia and eastern Turkey. The iconic city was often referred to as the "City of 1,001 Churches," though the number was significantly less. To date, 50 churches, 33 cave chapels and 20 chapels have been excavated by archaeologists and historians.
