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Shonkinite
Shonkinite is an intrusive igneous rock found in few places in the world. It is unique in having low silica, feldspathoid minerals, and large blocky crystals of black augite. It makes up much of the hard dark grey rock comprising certain mountains and buttes in Montana that are remnants of laccoliths and stocks, such as the Highwood mountains. Composition Shonkinite is an intrusive igneous rock. More specifically, it is a mafic foidal (feldspathoid bearing) syenite, a holocrystalline (completely crystalline) intrusive rock which, , is composed of potassic feldspar in the form of sanidine, nepheline, augite, biotite, and olivine. Shonkinite is also used for mafic nepheline syenite with aegerine-augite as the pyroxene, and with the addition of plagioclase (andesine to labradorite). Nepheline in shonkinite from the is largely altered to natrolite and stilbite. The close view of the rocks in the Adel mountains show large glossy crystals of augite in a dark grey matrix made up of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shonkinite From Mountain Pass In California
Shonkinite is an intrusive igneous rock found in few places in the world. It is unique in having low silica, feldspathoid minerals, and large blocky crystals of black augite. It makes up much of the hard dark grey rock comprising certain mountains and buttes in Montana that are remnants of laccoliths and stocks, such as the Highwood mountains. Composition Shonkinite is an intrusive igneous rock. More specifically, it is a mafic foidal (feldspathoid bearing) syenite, a holocrystalline (completely crystalline) intrusive rock which, , is composed of potassic feldspar in the form of sanidine, nepheline, augite, biotite, and olivine. Shonkinite is also used for mafic nepheline syenite with aegerine-augite as the pyroxene, and with the addition of plagioclase (andesine to labradorite). Nepheline in shonkinite from the is largely altered to natrolite and stilbite. The close view of the rocks in the Adel mountains show large glossy crystals of augite in a dark grey matrix made up of s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shonkin Sag
The Shonkin Sag is a prehistoric fluvioglacial landform located along the northern edge of the Highwood Mountains in the state of Montana in the United States. The Sag is a river channel formed by the Missouri River and glacial meltwater pouring from Glacial Lake Great Falls. It is one of the most famous prehistoric meltwater channels in the world. Location and size Shonkin Sag is located in central Montana. It begins south of Highwood, Montana, (about east of the city of Great Falls, Montana, Great Falls) and runs in an easterly direction for about until it reaches the Judith River."Societies and Academies: Geological Society of Washington." ''Science (journal), Science.'' May 7, 1895, p. 559-560. It varies from to in width and is about deep. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adel Mountains Volcanic Field
The Adel Mountains Volcanic Field (also known as the Adel Mountains, Adel Volcanics, and Adel Mountain Volcanics) is an ancient volcanic field of heavily eroded 75-million-year-oldGunderson, Jay A. and Sheriff, Steven D. "A New Late Cretaceous Paleomagnetic Pole from the Adel Mountains, West Central Montana." ''Journal of Geophysical Research.'' 96:B1 (January 10, 1991).Harlan, Stephen S.; Geissman, John W.; Snee, Lawrence W.; and Reynolds, Richard L. "Late Cretaceous Remagnetization of Proterozoic Mafic Dikes, Southern Highland Mountains, Southwestern Montana: A Paleomagnetic and 40Ar/39Ar Study." ''Geological Society of America Bulletin.'' 108:6 (June 1996). igneous rocks about 40 miles long and 20 miles wide (800 square miles, or 2,071 square kilometers)Merrill-Maker, Andrea. ''Montana Almanac.'' 2d ed. Guilford, Conn.: Globe Pequot, 2005. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aegerine
Aegirine is a member of the clinopyroxene group of inosilicate minerals. Aegirine is the sodium endmember of the aegirine-augite series. Aegirine has the chemical formula Na Fe Si2 O6 in which the iron is present as Fe3+. In the aegirine-augite series the sodium is variably replaced by calcium with iron(II) and magnesium replacing the iron(III) to balance the charge. Aluminium also substitutes for the iron(III). Acmite is a fibrous, green-colored variety. Aegirine occurs as dark green monoclinic prismatic crystals. It has a glassy luster and perfect cleavage. Its Mohs hardness varies from 5 to 6, and its specific gravity is between 3.2 and 3.4. This mineral commonly occurs in alkalic igneous rocks, nepheline syenites, carbonatites and pegmatites. It also appears in regionally metamorphosed schists, gneisses, and iron formations; in blueschist facies rocks, and from sodium metasomatism in granulites. It may occur as an authigenic mineral in shales and marls. It occurs in associat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Highwood Mountains
The Highwood Mountains are an island range (sub-range of the Rockies entirely surrounded by prairie) which cover approximately 4,659 km² (1,799 sq mi) of the Central Montana Alkalic Province in north central Montana in the U.S. They are in Chouteau, Judith Basin and Cascade counties and lie east of Great Falls and Benton Lake National Wildlife Refuge, at the northern end of the Lewis and Clark National Forest. The mountains were included in Highwood Mountains National Forest until 1908, when the unit became part of Lewis and Clark National Forest. Nearby are Highwood, Montana and the Missouri River above the mouth of the Marias River. The highest point in the Highwood Mountains is Highwood Baldy at 2338 meters (7670 ft). The area has volcanic origins and is rich in potash. Many of the extrusive rocks and some of the dike rocks contain abundant phenocrysts of a clear analcime that appears to be primary. Pseudoleucite is an abundant constituent of many of the igneous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timor
Timor is an island at the southern end of Maritime Southeast Asia, in the north of the Timor Sea. The island is East Timor–Indonesia border, divided between the sovereign states of East Timor on the eastern part and Indonesia on the western part. The Indonesian part, also known as West Timor, constitutes part of the Provinces of Indonesia, province of East Nusa Tenggara. Within West Timor lies an exclave of East Timor called Oecusse District. The island covers an area of . The name is a variant of ''timur'', Malay language, Malay for "east"; it is so called because it lies at the eastern end of the Lesser Sunda Islands. Mainland Australia is less than 500 km away, separated by the Timor Sea. Language, ethnic groups and religion Anthropologists identify eleven distinct Ethnolinguistic group, ethno-linguistic groups in Timor. The largest are the Atoni of western Timor and the Tetum of central and eastern Timor. Most indigenous Timorese languages belong to the Timorâ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ontario
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Canada, it is Canada's most populous province, with 38.3 percent of the country's population, and is the second-largest province by total area (after Quebec). Ontario is Canada's fourth-largest jurisdiction in total area when the territories of the Northwest Territories and Nunavut are included. It is home to the nation's capital city, Ottawa, and the nation's most populous city, Toronto, which is Ontario's provincial capital. Ontario is bordered by the province of Manitoba to the west, Hudson Bay and James Bay to the north, and Quebec to the east and northeast, and to the south by the U.S. states of (from west to east) Minnesota, Michigan, Ohio, Pennsylvania, and New York. Almost all of Ontario's border with the United States f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mountain Pass, California
Mountain Pass is an unincorporated area, unincorporated community in San Bernardino County, California, San Bernardino County, California, United States. It is situated on Interstate 15 in the southeast mountainous desert region of the state approximately from the Nevada border at an elevation of —the highest point along I-15 between California and Nevada. It has a population of 30. The most prominent feature of the town, and its reason for existence, is the Mountain Pass Mine, an open pit mine for rare-earth elements. The mine and its associated processing facilities are owned by MP Materials, which purchased the assets out of bankruptcy on July 10, 2017. Climate Typical of the High Desert (California), High Desert, Mountain Pass has a cold semi-arid climate (Köppen climate classification ''BSk''), Winters are chilly but also sunny, with daytime highs around 50 and nighttime lows just below freezing. Summers are hot and somewhat wetter, with July, the hottest month, havin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbia, and Saskatchewan to the north. It is the fourth-largest state by area, the eighth-least populous state, and the third-least densely populated state. Its state capital is Helena. The western half of Montana contains numerous mountain ranges, while the eastern half is characterized by western prairie terrain and badlands, with smaller mountain ranges found throughout the state. Montana has no official nickname but several unofficial ones, most notably "Big Sky Country", "The Treasure State", "Land of the Shining Mountains", and " The Last Best Place". The economy is primarily based on agriculture, including ranching and cereal grain farming. Other significant economic resources include oil, gas, coal, mining, and lumber. The health ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stilbite
Stilbite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, stilbite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named: * Stilbite-Ca * Stilbite-Na Stilbite-Ca, by far the more common of the two, is a hydrous calcium sodium and aluminium silicate, Na Ca4( Si27 Al9) O72·28( H2 O). In the case of stilbite-Na, sodium dominates over calcium. The species are visually indistinguishable, and the series name stilbite is still used whenever testing has not been performed. History At one time heulandite and stilbite were considered to be identical minerals. After they were found to be two separate species, in 1818, the name desmine ("a bundle") was proposed for stilbite, and this name is still employed in Germany. The English name "stilbite" is from the Greek stilbein = to shine, because of the pearly luster of the fa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Natrolite
Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula . The type locality is Hohentwiel, Hegau, Germany. It was named natrolite by Martin Heinrich Klaproth in 1803. The name is derived from ''natron'' (), the Greek word for soda, in reference to the sodium content, and ''lithos'' (), meaning stone. Needle stone or needle-zeolite are other informal names, alluding to the common acicular habit of the crystals, which are often very slender and are aggregated in divergent tufts. The crystals are frequently epitaxial overgrowths of natrolite, mesolite, and gonnardite in various orders. Properties Larger crystals most commonly have the form of a square prism terminated by a low pyramid, the prism angle being nearly a right angle. The crystals are tetragonal in appearance, though actually orthorhombic. There are perfect cleavages parallel to the faces of the prism. The mineral also often occurs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
