|
Blairmorite
Blairmorite is a very rare porphyritic volcanic rock named after the community of Blairmore in southwestern Alberta, Canada.Johannsen, A. 1933. A descriptive petrography of the igneous rocks, Appendix III, p. 244. Univ. of Chicago Press. It is characterized by dominant analcime phenocrysts in a matrix of analcime, sanidine and alkalic pyroxene with accessory titanite, melanite and nepheline. It is a leucocratic variety of analcimite (a foidite). Blairmorite has also been described as an analcime-rich variety of phonolite. This extrusive igneous rock is known from only two geological formations worldwide. The foremost blairmorite occurrence is the Crowsnest Formation in the Canadian province of Alberta where it is associated with agglomerates and tuffs from explosive eruptions. The other locality is the Lupata Gorge in Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country locat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crowsnest Formation
The Crowsnest Formation, also called the Crowsnest Volcanics, is a geological formation in southwestern Alberta, Canada, on the southwestern margin of the Western Canada Sedimentary Basin. It was named for the Crowsnest Pass near Coleman, Alberta. The formation consists mostly of pyroclastic rocks that were laid down in a series of explosive eruptions about 100 million years ago during the Albian stage of the Early Cretaceous epoch. It contains unusual minerals such as melanite (a variety of andradite garnet) and analcime (a variety of zeolite). Lithology and mineralogy The formation contains pyroclastic flows, lahars, agglomerates, tuffs and ash-fall deposits, as well as volcanic-rich sandstones and other sediments.Leckie, D. and Burden, E.T. 2001. Stratigraphy, sedimentology, and palynology of the Cretaceous (Albian) Beaver Mines, Mill Creek, and Crowsnest Formations (Blairmore Group) of southwestern Alberta. Geological Survey of Canada, Bulletin 563, 103 p. The whole-rock chemis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blairmore, Alberta
Blairmore is a community in the Rocky Mountains within the Municipality of Crowsnest Pass in southwest Alberta, Canada. It was formerly incorporated as a town prior to 1979 when it amalgamated with four other municipalities to form Crowsnest Pass. Blairmore is the principal commercial centre of Crowsnest Pass. History Originally a Canadian Pacific Railway stop called Tenth Siding or The Springs (for the cold sulphur spring to the east), the settlement was renamed Blairmore in November 1898 and it got a post office the following year. A ten-year dispute over land ownership between the CPR station agent and the section foreman stunted early development. The community was incorporated as the Village of Blairmore on September 3, 1901. Blairmore's principal industry was lumber and, after 1907, coal. Other industries soon followed. Blairmore incorporated as a town on September 29, 1911. With the declining fortunes of the nearby community of Frank, Blairmore soon became the region's ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phonolite
Phonolite is an uncommon extrusive rock, of intermediate chemical composition between felsic and mafic, with texture ranging from aphanitic (fine-grained) to porphyritic (mixed fine- and coarse-grained). Phonolite is a variation of the igneous rock trachyte that contains nepheline or leucite rather than quartz. Its intrusive equivalent is nepheline syenite. Phonolite is typically fine grained and compact. The name ''phonolite'' comes from the Ancient Greek meaning "sounding stone" due to the metallic sound it produces if an unfractured plate is hit; hence, the English name ''clinkstone'' is given as a synonym. Formation Unusually, phonolite forms from magma with a relatively low silica content, generated by low degrees of partial melting (less than 10%) of highly aluminous rocks of the lower crust such as tonalite, monzonite and metamorphic rocks. Melting of such rocks to a very low degree promotes the liberation of aluminium, potassium, sodium and calcium by melting of f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leucocratic
In geology, felsic is a modifier describing igneous rocks that are relatively rich in elements that form feldspar and quartz.Marshak, Stephen, 2009, ''Essentials of Geology,'' W. W. Norton & Company, 3rd ed. It is contrasted with mafic rocks, which are relatively richer in magnesium and iron. Felsic refers to silicate minerals, magma, and rocks which are enriched in the lighter elements such as silicon, oxygen, aluminium, sodium, and potassium. Felsic magma or lava is higher in viscosity than mafic magma/lava. Felsic rocks are usually light in color and have specific gravities less than 3. The most common felsic rock is granite. Common felsic minerals include quartz, muscovite, orthoclase, and the sodium-rich plagioclase feldspars (albite-rich). Terminology In modern usage, the term ''acid rock'', although sometimes used as a synonym, normally now refers specifically to a high-silica-content (greater than 63% SiO2 by weight) volcanic rock, such as rhyolite. Older, broader usage ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Rocks
Volcanic rock (often shortened to volcanics in scientific contexts) is a Rock (geology), rock formed from lava erupted from a volcano. In other words, it differs from other igneous rock by being of Volcano, volcanic origin. Like all rock types, the concept of volcanic rock is artificial, and in nature volcanic rocks grade into Subvolcanic rock, hypabyssal and metamorphic rocks and constitute an important element of some sediments and sedimentary rocks. For these reasons, in geology, volcanics and shallow hypabyssal rocks are not always treated as distinct. In the context of Precambrian shield (geology), shield geology, the term "volcanic" is often applied to what are strictly metavolcanic rocks. Volcanic rocks and sediment that form from magma erupted into the air are called "volcaniclastics," and these are technically sedimentary rocks. Volcanic rocks are among the most common rock types on Earth's surface, particularly in the oceans. On land, they are very common at plate bound ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mozambique
Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi and Zambia to the northwest, Zimbabwe to the west, and Eswatini and South Africa to the southwest. The sovereign state is separated from the Comoros, Mayotte and Madagascar by the Mozambique Channel to the east. The capital and largest city is Maputo. Notably Northern Mozambique lies within the monsoon trade winds of the Indian Ocean and is frequentely affected by disruptive weather. Between the 7th and 11th centuries, a series of Swahili port towns developed on that area, which contributed to the development of a distinct Swahili culture and language. In the late medieval period, these towns were frequented by traders from Somalia, Ethiopia, Egypt, Arabia, Persia, and India. The voyage of Vasco da Gama in 1498 marked the arrival of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lupata Gorge
The Lupata Gorge is a gorge on the Zambezi River in Mozambique Mozambique (), officially the Republic of Mozambique ( pt, Moçambique or , ; ny, Mozambiki; sw, Msumbiji; ts, Muzambhiki), is a country located in southeastern Africa bordered by the Indian Ocean to the east, Tanzania to the north, Malawi .... It marks the division between the Middle Zambezi and Lower Zambezi. Landforms of Mozambique Canyons and gorges of Africa {{Mozambique-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosive Eruption
In volcanology, an explosive eruption is a volcanic eruption of the most violent type. A notable example is the 1980 eruption of Mount St. Helens. Such eruptions result when sufficient gas has dissolved under pressure within a viscous magma such that expelled lava violently froths into volcanic ash when pressure is suddenly lowered at the vent. Sometimes a lava plug will block the conduit to the summit, and when this occurs, eruptions are more violent. Explosive eruptions can expel as much as per second of rocks, dust, gas and pyroclastic material, averaged over the duration of eruption, that travels at several hundred meters per second as high as into the atmosphere. This cloud may subsequently collapse, creating a fast-moving pyroclastic flow of hot volcanic matter. Stages of an explosive eruption An explosive eruption begins with some form of blockage in the crater of a volcano that prevents the release of gases trapped in highly viscous andesitic or rhyolitic magma. The pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tuff
Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock containing 25% to 75% ash is described as tuffaceous (for example, ''tuffaceous sandstone''). Tuff composed of sandy volcanic material can be referred to as volcanic sandstone. Tuff is a relatively soft rock, so it has been used for construction since ancient times. Because it is common in Italy, the Romans used it often for construction. The Rapa Nui people used it to make most of the ''moai'' statues on Easter Island. Tuff can be classified as either igneous or sedimentary rock. It is usually studied in the context of igneous petrology, although it is sometimes described using sedimentological terms. Tuff is often erroneously called tufa in guidebooks and in television programmes. Volcanic ash The material that is expelled in a volcanic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Agglomerate
Agglomerate (from the Latin ''agglomerare'' meaning "to form into a ball") is a coarse accumulation of large blocks of volcanic material that contains at least 75% bombs. Volcanic bombs differ from volcanic blocks in that their shape records fluidal surfaces: they may, for example, have ropy, cauliform, scoriaceous, folded, spindle, spatter, ribbon, ragged, or amoeboid shapes. Globular masses of lava may have been shot from the crater at a time when partly molten lava was exposed, and was frequently shattered by sudden outbursts of steam. These bombs were viscous at the moment of ejection and by rotation in the air acquired their shape. They are commonly in diameter, but specimens as large as have been observed. There is less variety in their composition at any one volcanic centre than in the case of the lithic blocks, and their composition indicates the type of magma being erupted. Agglomerates are typically found near volcanic vents and within volcanic conduits, where they m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geological Formation
A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by Abraham Gottlob Wer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Igneous Rock
Igneous rock (derived from the Latin word ''ignis'' meaning fire), or magmatic rock, is one of the three main The three types of rocks, rock types, the others being Sedimentary rock, sedimentary and metamorphic rock, metamorphic. Igneous rock is formed through the cooling and solidification of magma or lava. The magma can be derived from Partial melting, partial melts of existing rocks in either a Terrestrial planet, planet's mantle (geology), mantle or crust (geology), crust. Typically, the melting is caused by one or more of three processes: an increase in temperature, a decrease in pressure, or a change in composition. Solidification into rock occurs either below the surface as intrusive rocks or on the surface as extrusive (geology), extrusive rocks. Igneous rock may form with crystallization to form granular, crystalline rocks, or without crystallization to form Volcanic glass, natural glasses. Igneous rocks occur in a wide range of geological settings: shields, platforms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
.jpg "Click for more on -> Blairmore, Alberta")
