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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 Canadian Sedimentary Basin, 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 volcanic ash, 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 C ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blairmorite From The Crowsnest Formation
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. Blairmorite has been described as a leucocratic variety of analcimite (a foidite) or 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, is a country located in Southeast Africa bordered by the Indian Ocean to the east, Tanzania to t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Type Section
In geology, a stratotype or type section is the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary. If the stratigraphic unit is layered, it is called a stratotype, whereas the standard of reference for unlayered rocks is the type locality. Also it can be defined as "The particular sequence of strata chosen as standard of reference of a layered stratigraphic unit." When a stratigraphic unit is nowhere fully exposed, the original type section may be supplemented with reference sections covering the full thickness of the unit. A reference section may also be defined when the original type section is poorly exposed, or for historical units which were designated without specifying a type section according to more modern standards. See also * Global Boundary Stratotype Section and Point A Global Boundary Stratotype Section and Point (GSSP), sometimes referred to as a golden spike, is an internationally agre ... [...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 (geology), 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 ... [...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''). A pyroclastic rock containing 25–75% volcanic bombs or volcanic blocks is called tuff breccia. 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 t ... [...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 the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lahars
A lahar (, from ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are often extremely destructive and deadly; they can flow tens of metres per second, they have been known to be up to deep, and large flows tend to destroy any structures in their path. Notable lahars include those at Mount Pinatubo in the Philippines and Nevado del Ruiz in Colombia, the latter of which killed more than 20,000 people in the Armero tragedy. Etymology The word ''lahar'' is of Javanese origin. Berend George Escher introduced it as a geological term in 1922. Description The word ''lahar'' is a general term for a flowing mixture of water and pyroclastic debris. It does not refer to a particular rheology or sediment concentration. Lahars can occur as normal stream flows (sediment concentration of less than 30%), hyper-concentrated stream flows (sediment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Crowsnest Volcanics 1371
Crows Nest, Crow's Nest or Crowsnest may refer to: * Crow's nest, a structure in the upper part of the main mast of a ship, or a structure that is used as a lookout point Places * Crows Nest, New South Wales, Australia ** Crows Nest railway station * Crows Nest, Queensland, Australia ** Crows Nest National Park ** Shire of Crows Nest ** Electoral district of Crows Nest * Crow's Nest, Nova Scotia, Canada * Crowsnest Highway, in British Columbia and Alberta, Canada * Crowsnest Pass, a mountain pass on the Alberta–British Columbia border, Canada ** Crowsnest Mountain ** Crowsnest Provincial Park * Crowsnest River, Alberta, Canada * Crow's Nest (Hong Kong), a hill * Crow's Nest, Cornwall, England, United Kingdom * Crows Nest, Indiana, U.S. * Crow's Nest, Montana, U.S. near the Battle of the Little Bighorn in 1876 * Crow's Nest (New York), U.S. a mountain * Crows Nest (Wilmington, Vermont), U.S., a historic property * Crow's Nest Natural Area Preserve, in Stafford County, Virgini ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zeolite
Zeolites are a group of several microporous, crystalline aluminosilicate minerals commonly used as commercial adsorbents and catalysts. They mainly consist of silicon, aluminium, oxygen, and have the general formula ･y where is either a metal ion or H+. The term was originally coined in 1756 by Swedish mineralogist Axel Fredrik Cronstedt, who observed that rapidly heating a material, believed to have been stilbite, produced large amounts of steam from water that had been adsorbed by the material. Based on this, he called the material ''zeolite'', from the Greek , meaning "to boil" and , meaning "stone". Zeolites occur naturally, but are also produced industrially on a large scale. , 253 unique zeolite frameworks have been identified, and over 40 naturally occurring zeolite frameworks are known. Every new zeolite structure that is obtained is examined by the International Zeolite Association Structure Commission (IZA-SC) and receives a three-letter designation. Character ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analcime
Analcime (; ) or analcite is a white, gray, or colorless tectosilicate mineral. Analcime consists of hydrated sodium aluminium silicate in cubic crystalline form. Its chemical formula is NaAlSi2O6 · H2O. Minor amounts of potassium and calcium substitute for sodium. A silver-bearing synthetic variety also exists (Ag-analcite). Analcime is usually classified as a zeolite mineral, but structurally and chemically it is more similar to the feldspathoids. Analcime is not classified as an isometric crystal, as although the crystal structure appears to be isometric, it is usually off only by a fraction of an angle. However, there are truly isometric samples of the mineral, which makes its classification even more difficult. Due to the differences between the samples being too slight, there's no merit from having multiple species names, so as a result analcime is a common example for minerals occurring in multiple crystal systems and space groups. It was first described by French geolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Garnet
Garnets () are a group of silicate minerals that have been used since the Bronze Age as gemstones and abrasives. Garnet minerals, while sharing similar physical and crystallographic properties, exhibit a wide range of chemical compositions, defining distinct species. These species fall into two primary solid solution series: the pyralspite series (pyrope, almandine, spessartine), with the general formula [Mg,Fe,Mn]3Al2(SiO4)3; and the ugrandite series (uvarovite, grossular, andradite), with the general formula Ca3[Cr,Al,Fe]2(SiO4)3. Notable varieties of grossular include Grossular#Hessonite, hessonite and tsavorite. Etymology The word ''garnet'' comes from the 14th-century Middle English word ''gernet'', meaning 'dark red'. It is borrowed from Old French ''grenate'' from Latin language, Latin ''granatus,'' from ''granum'' ('grain, seed'). This is possibly a reference to ''mela granatum'' or even ''pomum granatum'' ('pomegranate', ''Punica granatum''), a plant whose fruits conta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Andradite
Andradite is a Mineralogy, mineral species of the Garnet, garnet group. It is a Silicate minerals#Nesosilicates, nesosilicate, with chemical formula Ca3Fe2Si3O12. Andradite includes three varieties: * ''Colophonite'': a historical variety found in the Scandinavian islands, brownish or reddish in color, often opaque or translucent.''Olga Bortnik''. All about precious stones. ― Moscow: Harvest, 2011. * ''Demantoid'': Vivid green in color, one of the most valuable and rare stones in the gemology, gemological world. * ''Melanite'': Black in color due to limited substitution of titanium for iron. Also known as "titanian andradite". Forms a solid solution with morimotoite and schorlomite depending on titanium and iron content. Mindat.org * ''Topazolite'': Yellow-green in color and sometimes of high enough quality to be cut into a faceted gemstone, it is rarer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
