Image GabbroRockCreek1.jpg thumb Gabbro specimen Rock Creek Canyon, eastern Sierra Nevada U.S. Sierra Nevada , California. Image GabbroRockCreek2.jpg thumb Close up of gabbro specimen Rock Creek Canyon, eastern Sierra Nevada, California. Image Gabbro pmg ss 2006.jpg thumb Photomicrograph of a thin section of gabbro. Gabbro IPAc en icon b r o refers to a large group of dark, coarse grained, intrusive ... majority of the Earth s surface is underlain by gabbro within the oceanic crust , produced by basalt ... right A gabbro landscape on the main ridge of the Cuillin , Isle of Skye , Scotland . Image SierraXenolith.JPG thumb Gabbro as a xenolith in a granite , eastern Sierra Nevada U.S. Sierra Nevada , Rock Creek Canyon, California. Gabbro is dense, greenish or dark colored and contains pyroxene , plagioclase , amphibole , and olivine olivine gabbro when olivine is present in a large amount . The pyroxene ... oxides such as magnetite , ilmenite , and ulvospinel . Gabbro is generally coarse grained, with crystals in the size range of 1 mm or greater. Finer grained equivalents of gabbro are called diabase , although the vernacular term microgabbro is often used when extra descriptiveness is desired. Gabbro ... are essentially coarse grained gabbro, although these may exhibit acicular crystal habits. Gabbro ... plagioclase oikocrysts have grown earlier than the groundmass minerals. Distribution Gabbro can be formed .... Cumulate gabbros are more properly termed pyroxene plagioclase orthocumulate. Gabbro is an essential ... and IV Sheeted dyke complex sheeted dyke zone to massive gabbro zone . Long belts of gabbroic intrusions ... basalt volcanism. Uses Gabbro often contains valuable amounts of chromium , nickel , cobalt , gold , silver , platinum , and copper sulfide s. Ocellar varieties of gabbro can be used as ornamental ..., also under the misnomer of black granite . Etymology Gabbro was named by the German geologist ... program gabbro petrology http www.livescience.com forcesofnature 060420 earth drill.html Scientists ... more details
Gabbro Hills Coord 84 42 S 173 0 W display inline,title is a group of rugged ridges and coastal hills which borders the Ross Ice Shelf between the Barrett and Gough Glaciers and extends south to Ropebrake Pass . So named by the Southern Party of New Zealand Geological Survey Antarctic Expedition NZGSAE 1963 64 because of the prevalence of gabbro , a dark, plutonic rock, in the area. usgs gazetteer Category Mountain ranges of Antarctica Category Dufek Coast DufekCoast geo stub ... more details
orphan date March 2010 Gabbro Crest Coord 83 28 S 50 22 W display inline,title is the crest c. 1,750 m of the mountain spur between Sheriff Cliffs and Vigen Cliffs on the southeast edge of Saratoga Table , Forrestal Range , q.v. So named in 1979 by Advisory Committee on Antarctic Names US ACAN , at the suggestion of Arthur B. Ford , United States Geological Survey USGS geologist, from the gabbro dominant rock type of the Forrestal Range. usgs gazetteer Category Mountains of Edith Ronne Land Category Pensacola Mountains EdithRonneLand geo stub ... more details
An equigranular material is composed chiefly of crystals of similar orders of magnitude to one another. Basalt and gabbro commonly exhibit an equigranular Rock microstructure texture . References Reflist unsourced date November 2010 Category Petrology petrology stub ... more details
Theralite from Greek to pursue is, in petrology , the name given to calcic feldspathoid foildal gabbro , a plutonic hylocrystaline rock consisting of augite , olivine , calcic plagioclase labradorite , and nepheline , along with accessories including biotite , magnetite , ilmenite and analcime . Theralite is the intrusive equivalent of nepheline basanite , a foidal basalt with essential calic plagioclase and essential olivine. Tephrite is fiodal basalt with essential calic plagioclase but without essential olivine. It is essentially the volcanic equivalent of essexite . The discovery of theralite was looked forward to with interest as completing the series of basic rocks containing nepheline as an essential constituent. With the increase in silica SiO sub 2 sub and the concomitant reduction in nepheline, theralite becomes gabbro. With a decrease in silica and reduction in olivine theralite grades into teschenite and with the addition of sodic feldspar, grades into essexite. With a further reduction in silica such that there is no feldspar these rocks become melteigites. With the addition of alkali feldspar replacing or becoming more dominant than calcic plagioclase theralites grade into foidal syenite, including shonkinite . Properly theralite is only for a specific type of calcic foidal gabbro, those with essential nepheline and without essential analcime or sodic feldspar. Teschenites Teschenites were once considered part of the theralite group. They contain essential pyroxene, olivine and analcime. Modern petrology would classify the teschenites as an analcime bearing gabbro. They are petrogenetically unrelated to nepheline gabbros as analcime is not produced by the same genetic processes. Essexites Essexite is a form of silica undersaturaed pyroxene gabbro, containing nepheline and orthoclase as essential constituents, though often in small proportions. Essexites can be considered to represent the intrusive equivalent of an alkaline basalt. Essexites are usually ... more details
Refimprove date December 2007 Mafic is an adjective describing a silicate mineral or rock that is rich in magnesium and iron the term is a portmanteau of the words magnesium and ferric . ref http www.glossary.oilfield.slb.com Display.cfm?Term mafic Schlumberger Oilfield Glossary ref Most mafic minerals are dark in color and the relative density is greater than 3. Common rock forming mafic minerals include olivine , pyroxene , amphibole , and biotite . Common mafic rocks include basalt , dolerite and gabbro . In terms of chemistry, mafic rocks are on the other side of the rock spectrum from the felsic rocks. The term roughly corresponds to the older basic rock class. Mafic lava , before cooling, has a low viscosity , in comparison to felsic lava, due to the lower silica content in mafic magma. Water and other volatiles can more easily and gradually escape from mafic lava, so eruptions of volcanoes made of mafic lavas are less explosively violent than felsic lava eruptions. Most mafic lava volcanoes are oceanic volcanoes, like those in Hawaii . class wikitable Rock Texture Name of Mafic Rock Pegmatite Pegmatitic Gabbro pegmatite Coarse grained phaneritic Gabbro Coarse grained and porphyritic Porphyritic gabbro Fine grained aphanitic Basalt Fine grained and porphyritic Porphyritic basalt Pyroclastic Basalt tuff or breccia Vesicular texture Vesicular Vesicular basalt Amygdaloidal Amygdaloidal basalt Many small vesicles Scoria Glassy texture Glassy Tachylyte , sideromelane , palagonite See also QAPF diagram List of minerals List of rock types References Reflist igneous rocks Category Mineralogy Category Igneous petrology ar cs Mafity de Mafische Minerale et V rvilised mineraalid es M fico fr Mafique it Femico he nl Mafisch ja no Mafisk mineral nn Mafiske mineral pt M fico simple Mafic sk Mafick sl Mafi nost fi Mafinen uk vi Mafic ... more details
Sheriff Cliffs Coord 83 24 S 50 37 W display inline,title is a set of cliffs rising to about 1,750 m to the west of Gabbro Crest , Saratoga Table , in the Forrestal Range , Pensacola Mountains . Named by Advisory Committee on Antarctic Names US ACAN in 1979 after Steven D. Sheriff , geologist, Western Washington State University , Bellingham, WA, who worked in this area, 1978 79. usgs gazetteer Category Cliffs of Edith Ronne Land EdithRonneLand geo stub ... more details
Ropebrake Pass coor dm 84 45 S 173 25 W is a steep, narrow snow pass between the south end of Gabbro Hills and Mount Llano , permitting passage between the Barrett Glacier Barrett and Gough Glacier s. So named by the Southern Party of New Zealand Geological Survey Antarctic Expedition NZGSAE 1963 64 because of the large number of rope brakes used in its crossing. usgs gazetteer Category Mountain passes of the Ross Dependency Category Dufek Coast DufekCoast geo stub ... more details
Mount Roth coor dm 84 35 S 172 22 W is a rock peak 870 m located 3 nautical miles 6 km east of Mount Justman in the northeast corner of Gabbro Hills , near the edge of the Ross Ice Shelf . Discovered and photographed by the Byrd Antarctic Expedition 1928 30 and named for Benjamin Roth , mechanic and U.S. Army representative on that expedition. usgs gazetteer DEFAULTSORT Roth Category Mountains of the Ross Dependency Category Dufek Coast DufekCoast geo stub ... more details
Unreferenced stub auto yes date December 2009 Norite is a mafic intrusive igneous rock composed largely of the calcium rich plagioclase labradorite and hypersthene with olivine . Norite is essentially indistinguishable from gabbro without thin section study under the petrographic microscope . It occurs with gabbro and other mafic to ultramafic rocks in layered intrusion s which are often associated with platinum ore bodies such as in the Bushveld Igneous Complex in South Africa , the Skaergaard intrusion Skaergaard igneous complex of Greenland , and the Stillwater igneous complex in Montana , USA . Norite is also the basal igneous rock of the Sudbury Basin complex in Ontario which is the site of a impact event meteorite impact and the world s second largest nickel mining region. Norite is a common rock type of the Moon rock Apollo samples . On a smaller scale, norite can be found in small localized intrusion s such as the Gombak Norite in Bukit Gombak , Singapore . The name Norite is derived from the Norwegian name for Norway Norge . Category Igneous petrology Category Ultramafic rocks Petrology stub cs Norit de Norit es Norita fr Norite it Norite he lt Noritas nl Noriet pl Noryt pt Norito uk ... more details
Unreferenced date December 2009 An intrusive rock, similar to dolerite , but with an excess of quartz . Dolerite is similar in composition to basalt , which is eruptive from volcano es , and gabbro , which is plutonic . The differing crystal sizes are due to the different rate of cooling, basalt cools quickly and has a very fine structure, while gabbro cools very slowly, at great depth, and large crystals develop. Dolerite is intermediate. Quartz dolerite is very common in central Scotland , in intrusive formations, Sill geology sill s and Dyke geology dyke s, and is widely quarried for roadstone. It was used with some success for making millstones at one time, the Millstone Grit part of the Carboniferous strata not being present in Scotland , but it is no longer used for this purpose, and would probably be illegal now due to the formation of small quartz and other silicate particles, which could cause the serious respiratory disease silicosis . In Scotland quartz dolerite is commonly known as whin or whinstone. Quartz dolerite contains many cooling fractures and weathers badly, becoming unstable. It is not uncommon for large boulders to break loose, and significant rockfalls are not uncommon. It is regarded as dangerous as far as climbing is concerned. DEFAULTSORT Quartz Dolerite Category Igneous rocks Petrology stub ... more details
File Troctolite76535.jpg thumb Troctolite 76535 from the Apollo 17 landing site Troctolite is a mafic intrusive rock type. It consists essentially of major but variable amounts of olivine and calcic plagioclase along with variable minor pyroxene . It is an olivine rich, pyroxene depleted relative of gabbro . However, unlike gabbro, no troctolite corresponds in composition to a partial melt of peridotite. Thus, troctolite is necessarily a cumulate of crystals that have fractionated from melt. Troctolite is found in some layered intrusion s such as in the Archean Windimurra intrusion of West Australia , the Voisey s Bay nickel copper cobalt magmatic sulfide deposit of northern Labrador , ref http gac.esd.mun.ca gac 2001 seven sub program.asp?sess 98&form 10&abs no 237 Geology of the Voisey s Bay Deposits abstract ref the Stillwater igneous complex of Montana and the Tertiary R m Geology Rhum layered intrusion of the island of R m , Scotland . ref http www.turnstone.ca rhumal.htm Troctolite allivalite Isle of Rhum, northwestern Scotland ref Troctolite is also found in the Merensky Reef of the Bushveld Igneous Complex , South Africa and in The Lizard ophiolite in Cornwall . ref http www.projects.ex.ac.uk geomincentre 06The 20Lizard.pdf The Lizard ref References Commons Category Troctolite Reflist Blatt, Harvey and Robert J. Tracy, 1996, Petrology Igneous, Sedimentary and Metamorphic, 2nd ed., p. 72, Freeman, ISBN 0 7167 2438 3 Category Igneous rocks petrology stub cs Troktolit de Troktolith es Troctolita it Troctolite sv Troctolit ... more details
Image Intrusion types.svg thumb right Diagram showing the shape of a lopolith 7 A lopolith is a large igneous intrusion which is Lenticular geology lenticular in shape with a depressed central region. Lopoliths are generally concordant with the intruded stratum strata with Dike geology dike or funnel shaped feeder bodies below the body. The term was first defined and used by Frank Fitch Grout during the early 1900s in describing the Duluth gabbro complex in northern Minnesota and adjacent Ontario . Lopoliths typically consist of large layered intrusion s that range in age from Archean to Eocene . Examples include the Duluth gabbro , the Sudbury Igneous Complex of Ontario, the Bushveld igneous complex of South Africa , the Skaergaard complex of Greenland and the Humboldt lopolith of Nevada . The Sudbury occurrence has been attributed to an impact event and associated crustal melting. See also Laccolith References Blatt, Harvey and Robert J. Tracy, 1996, Petrology Igneous, Sedimentary and Metamorphic , 2nd ed., pp. 15 16, Freeman, ISBN 0 7167 2438 3 Guilbert, John M., and Park, Charles F., Jr. 1986 The Geology of Ore Deposits , Freeman, ISBN 0 7167 1456 6 Category Igneous rocks Category Petrology Geology stub de Lopolith es Lopolito he lt Lopolitas pl Lopolit ru sl Lopolit uk ... more details
Broom Hill is a hill and eponymous rural neighbourhood in Sooke , British Columbia . Its residential subdivisions surround Broom Hill proper, ref http archive.ilmb.gov.bc.ca bcgn bin bcg10?name 1143 Broom Hill hill ref which is composed of gabbro which rises to an elevation of 283 metres 928 feet . ref http bivouac.com MtnPg.asp?MtnId 14941 Canadian Mountain Encyclopedia entry Broom Hill ref Above the subdivisions, most of the terrain has a forest cover dominated by Douglas fir . References reflist coord 48 23 09 N 123 45 34 W display title Category Populated places in the Capital Regional District Category Hills of British Columbia BritishColumbiaCoast geo stub VictoriaNeighbourhoods ... more details
The Metchosin Igneous Complex is an ophiolite sequence in southwestern British Columbia , Canada , located at the southern end of Vancouver Island . It is the northernmost expression of the Crescent Terrane and consists of three rock units, including a basalt ic sequence, a sheeted dike geology dike complex and gabbro stocks. ref http adsabs.harvard.edu abs 1986Geo....14..602M Metchosin Igneous Complex, southern Vancouver Island Ophiolite stratigraphy developed in an emergent island setting ref See also Portal Volcanism of Canada Volcanism of Western Canada References reflist coord missing British Columbia Category Volcanism of British Columbia Category Southern Vancouver Island BritishColumbiaCoast geo stub Canada geology stub ... more details
Orphan date December 2010 Amphibole Peak Coord 84 44 S 173 26 W source GNIS display inline,title is, at convert 1660 m , the highest Summit topography peak in the Gabbro Hills , standing convert 4 nmi km 0 north of Mount Llano , in the Queen Maud Mountains of Antarctica . It was so named by the Southern Party of the New Zealand Geological Survey Antarctic Expedition 1963 64 because minerals of the Amphibole group were found on the peak. ref name gnis References Reflist refs ref name gnis cite gnis type antarid id 365 name Amphibole Peak accessdate 2011 05 10 ref usgs gazetteer id 365 Category Mountains of the Ross Dependency Category Dufek Coast DufekCoast geo stub ... more details
Barrett Glacier Coord 84 37 S 174 10 W source GNIS display inline,title is a glacier draining from the north slopes of the Prince Olav Mountains , about convert 15 nmi km 1 long, flowing between the Longhorn Spurs and the Gabbro Hills to the Ross Ice Shelf . It was named by the Southern Party of the New Zealand Geological Survey Antarctic Expedition 1963 64 for Peter J. Barrett , a geologist with that party. ref name gnis References Reflist refs ref name gnis cite gnis type antarid id 1013 name Barrett Glacier accessdate 2011 05 20 ref usgs gazetteer id 1013 Category Glaciers of the Ross Dependency Category Dufek Coast DufekCoast geo stub ... more details
Image Eulengebrigsbahn bridge abseiling.jpg right thumb Abseiling on a bridge in the Owl Mountains 2010 Eulengebirgsbahn Aktiengesellschaft AG was a Silesia n railway company. In 1899 1903 it gradually built a railway line connecting Dzier oni w Reichenbach today Dzier oni w with Radk w W nschelburg Radk w . ref http www.wuestewaltersdorf.de de eule eulengebirgsbahn.htm ref Regular traffic on the line was abolished, the section from cinawka rednia Mittelsteine to S upiec Schlegel still serves as an industrial siding for the local gabbro mine. ref http www.skn.pl oferta,diabaz.php ref References references See also commons category Kleinbahn List of former German railway companies Category Defunct railway companies of Germany cs Eulengebirgsbahn de Eulengebirgsbahn pl Kolej sowiog rska ... more details
Olliver Peak coord 84 34 S 173 33 W is a rock summit topography peak 630 m along the edge of Ross Ice Shelf . It stands at the east side of the mouth of Barrett Glacier and is the northwesternmost summit in Gabbro Hills . Named by Advisory Committee on Antarctic Names US ACAN for Commander George R. Olliver , U.S. Navy , who was injured in the crash of an Otter aircraft on December 22, 1955, following a take off from near Cape Bird . usgs gazetteer Category Mountains of Antarctica Category Dufek Coast DufekCoast geo stub ... more details
Orphan date December 2010 The Organ Pipes coor dm 82 37 S 52 42 W is a notable rock cliffs on the northwest side of Jaeger Table , south of Cairn Ridge , in the Dufek Massif , Pensacola Mountains . The name is suggested by the appearance of the feature caused by weathering along prominent vertical joints in the gabbro rock. Named by Arthur B. Ford , United States Geological Survey USGS geologist, leader of the USGS Pensacola Mountains survey party, 1978 79. usgs gazetteer DEFAULTSORT Organ Pipes Category Cliffs of Edith Ronne Land FilchnerRonne geo stub ... more details
Mount Justman coor dm 84 35 S 172 56 W is a mountain 740 m along the edge of Ross Ice Shelf , standing in the north part of Gabbro Hills , midway between Olliver Peak and Mount Roth . Named by Advisory Committee on Antarctic Names US ACAN for Lieutenant Commander L.G. Justman , U.S. Navy , Assistant Ship Operations Officer on the Staff of the Commander, U.S. Naval Support Force , Antarctica, 1964. usgs gazetteer DEFAULTSORT Justman Category Mountains of the Ross Dependency Category Dufek Coast DufekCoast geo stub ... more details
Orphan date December 2010 Polaris Peak coor dm 84 39 S 172 40 W is a rounded summit topography peak 970 m rising 4 nautical miles 7 km southwest of Mount Roth in the Gabbro Hills , Queen Maud Mountains . So named by the Southern Party of New Zealand Geological Survey Antarctic Expedition NZGSAE 1963 64 because they drove a Polaris motor toboggan to the summit. usgs gazetteer Category Mountains of the Ross Dependency Category Dufek Coast DufekCoast geo stub ... more details
Gough Glacier coor dm 84 42 S 171 35 W is a glacier about 25 nautical miles 46 km long, flowing from the north slopes of Prince Olav Mountains and the base of Lillie Range and trending northward to the Ross Ice Shelf , between Gabbro Hills and Bravo Hills . Named by the Southern Party of the New Zealand Geological Survey Antarctic Expedition NZGSAE 1963 64 for A.L. Gough , surveyor of the party. usgs gazetteer Category Glaciers of the Ross Dependency Category Dufek Coast DufekCoast geo stub ... more details
Orphan date April 2011 Magnetite Bluff coor dm 83 22 S 51 15 W is a bluff 2 nautical miles 3.7 km northeast of Mount Stephens on the west side of Saratoga Table , Forrestal Range . Named by Advisory Committee on Antarctic Names US ACAN , 1979, at the suggestion of Arthur B. Ford and following United States Geological Survey USGS geological work in the area, from the extensive occurrences of magnetite in the gabbro of this area which cause large magnetic anomalies over the Forrestal Range. usgs gazetteer Category Cliffs of Edith Ronne Land FilchnerRonne geo stub ... more details
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