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76-481: The Suncor Energy Centre , formerly the Petro-Canada Centre , is a 181,000-square-metre (1,950,000 sq ft) project composed of two granite and reflective glass -clad office towers of 32 floors and 52 floors, in the office core of downtown Calgary , Alberta. The Council on Tall Buildings and Urban Habitat lists the west tower (215 m or 705 ft as measured to top of the structure), as

152-537: A 115,000 square foot Doral warehouse at 1500 Northwest 95th Avenue for $ 16 million. In January 2023, Brookfield Properties purchased subsidiaries from Deutsche Bank A.G., acquiring Deutsche Bank's London and New York offices. In February 2024, the company opened offices in India and the UAE. The company is the owner of Zuccotti Park , a publicly accessible park adjacent to one of its office buildings near Wall Street in

228-547: A 15-year lease to remain in the towers. Major tenants of the Suncor Energy Centre include Suncor Energy Inc. , Precision Drilling Corporation , Taqa North, Crescent Point Energy, Enbridge, Direct Energy, PricewaterhouseCoopers and Weatherford Canada. Granite Granite is typical of a larger family of granitic rocks , or granitoids , that are composed mostly of coarse-grained quartz and feldspars in varying proportions. These rocks are classified by

304-461: A 25% interest in O&;Y Properties Corporation and O&Y Real Estate Investment Trust, expanding the company's real estate portfolio in four Canadian cities. In 2006, the company acquired Trizec Properties, which was founded in 1960 by William Zeckendorf , builder of Place Ville Marie . In 2010, it entered into London and Australian markets by acquiring the 100 Bishopsgate development site in

380-685: A 33% interest in Olympia & York Developments Ltd. , developers of the World Financial Center in New York, and in 1990, Brookfield acquired a 50% interest in a portfolio of office properties in Toronto, Denver and Minneapolis from BCE Development Corporation . In 1994, this holding was increased to 100% and included BCE Place, now Brookfield Place, Brookfield Properties' flagship office complex in Toronto. In 1996, Carena acquired

456-677: A 46% interest in World Financial Properties, a corporation formed from the bankruptcy of Olympia & York, which included three of the four towers of the World Financial Center, One Liberty Plaza , 245 Park Avenue in Manhattan. That year, Carena changed its name to Brookfield Properties Corporation. In 1997, Brookfield Properties purchased 45% of Gentra, Inc., owner of several commercial properties in Toronto. In 2000, Brookfield Properties acquired

532-460: A 49% interest in each of three former GGP super-regional malls to CBRE Group , and a 49% interest in three other former GGP malls to TIAA subsidiary Nuveen , seeking additional joint ventures for its newly acquired malls. The acquisition added 162 shopping malls comprising approximately 146 million sq ft (13.6 million m ) of gross leasable area to Brookfield's portfolio. In December 2018, Brookfield Properties took over

608-563: A basaltic magma to a granitic magma, but the quantities produced are small. For example, granitic rock makes up just 4% of the exposures in the South Sandwich Islands . In continental arc settings, granitic rocks are the most common plutonic rocks, and batholiths composed of these rock types extend the entire length of the arc. There are no indication of magma chambers where basaltic magmas differentiate into granites, or of cumulates produced by mafic crystals settling out of

684-520: A diapir it would expend far too much energy in heating wall rocks, thus cooling and solidifying before reaching higher levels within the crust. Fracture propagation is the mechanism preferred by many geologists as it largely eliminates the major problems of moving a huge mass of magma through cold brittle crust. Magma rises instead in small channels along self-propagating dykes which form along new or pre-existing fracture or fault systems and networks of active shear zones. As these narrow conduits open,

760-610: A granite that is derived from partial melting of metasedimentary rocks may have more alkali feldspar, whereas a granite derived from partial melting of metaigneous rocks may be richer in plagioclase. It is on this basis that the modern "alphabet" classification schemes are based. The letter-based Chappell & White classification system was proposed initially to divide granites into I-type (igneous source) granite and S-type (sedimentary sources). Both types are produced by partial melting of crustal rocks, either metaigneous rocks or metasedimentary rocks. I-type granites are characterized by

836-565: A high content of sodium and calcium, and by a strontium isotope ratio, Sr/ Sr, of less than 0.708. Sr is produced by radioactive decay of Rb, and since rubidium is concentrated in the crust relative to the mantle, a low ratio suggests origin in the mantle. The elevated sodium and calcium favor crystallization of hornblende rather than biotite. I-type granites are known for their porphyry copper deposits. I-type granites are orogenic (associated with mountain building) and usually metaluminous. S-type granites are sodium-poor and aluminum-rich. As

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912-824: A much higher proportion of clay with the Cecil soil series a prime example of the consequent Ultisol great soil group. Granite is a natural source of radiation , like most natural stones. Potassium-40 is a radioactive isotope of weak emission, and a constituent of alkali feldspar , which in turn is a common component of granitic rocks, more abundant in alkali feldspar granite and syenites . Some granites contain around 10 to 20 parts per million (ppm) of uranium . By contrast, more mafic rocks, such as tonalite, gabbro and diorite , have 1 to 5 ppm uranium, and limestones and sedimentary rocks usually have equally low amounts. Many large granite plutons are sources for palaeochannel -hosted or roll front uranium ore deposits , where

988-536: A peculiar mineralogy and geochemistry, with particularly high silicon and potassium at the expense of calcium and magnesium and a high content of high field strength cations (cations with a small radius and high electrical charge, such as zirconium , niobium , tantalum , and rare earth elements .) They are not orogenic, forming instead over hot spots and continental rifting, and are metaluminous to mildly peralkaline and iron-rich. These granites are produced by partial melting of refractory lithology such as granulites in

1064-808: A portfolio of Calgary office properties, including the Bankers Hall complex. In April 2001, the company lost out to Silverstein Properties, Inc. , on the lease of the World Trade Center in New York City before the complex was destroyed during the September 11 attacks . In 2003, Brookfield Properties completed the spin-off of Brookfield Homes, now part of Brookfield Residential , Brookfield Asset Management's U.S.-based home building business. In 2005, Brookfield Properties acquired

1140-568: A range of hills, formed by the metamorphic aureole or hornfels . Granite often occurs as relatively small, less than 100 km stock masses ( stocks ) and in batholiths that are often associated with orogenic mountain ranges. Small dikes of granitic composition called aplites are often associated with the margins of granitic intrusions . In some locations, very coarse-grained pegmatite masses occur with granite. Granite forms from silica-rich ( felsic ) magmas. Felsic magmas are thought to form by addition of heat or water vapor to rock of

1216-415: A result, they contain micas such as biotite and muscovite instead of hornblende. Their strontium isotope ratio is typically greater than 0.708, suggesting a crustal origin. They also commonly contain xenoliths of metamorphosed sedimentary rock, and host tin ores. Their magmas are water-rich, and they readily solidify as the water outgasses from the magma at lower pressure, so they less commonly make it to

1292-466: Is grus , which is often made up of coarse-grained fragments of disintegrated granite. Climatic variations also influence the weathering rate of granites. For about two thousand years, the relief engravings on Cleopatra's Needle obelisk had survived the arid conditions of its origin before its transfer to London. Within two hundred years, the red granite has drastically deteriorated in the damp and polluted air there. Soil development on granite reflects

1368-545: Is microgranite . The extrusive igneous rock equivalent of granite is rhyolite . Granitic rock is widely distributed throughout the continental crust . Much of it was intruded during the Precambrian age; it is the most abundant basement rock that underlies the relatively thin sedimentary veneer of the continents. Outcrops of granite tend to form tors , domes or bornhardts , and rounded massifs . Granites sometimes occur in circular depressions surrounded by

1444-517: Is 3–6·10 Pa·s. The melting temperature of dry granite at ambient pressure is 1215–1260 °C (2219–2300 °F); it is strongly reduced in the presence of water, down to 650 °C at a few hundred megapascals of pressure. Granite has poor primary permeability overall, but strong secondary permeability through cracks and fractures if they are present. A worldwide average of the chemical composition of granite, by weight percent, based on 2485 analyses: The medium-grained equivalent of granite

1520-520: Is a subsidiary of alternative asset management company Brookfield Asset Management . It is responsible for the asset management of the company's real estate portfolio, including office , multi-family residential , retail , hospitality , and logistics buildings. Brookfield Properties acquired General Growth Properties , one of the largest mall operators in the U.S., and merged it into Brookfield Properties in 2018. As of 2024, Brookfield Properties operates corporate offices in nine countries around

1596-410: Is an excess of aluminum beyond what can be taken up in feldspars (Al 2 O 3 > CaO + K 2 O + Na 2 O) are described as peraluminous , and they contain aluminum-rich minerals such as muscovite . The average density of granite is between 2.65 and 2.75 g/cm (165 and 172 lb/cu ft), its compressive strength usually lies above 200 MPa (29,000 psi), and its viscosity near STP

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1672-637: Is believed to have a mass of around 81 tonnes. It was the tallest temple in south India. Imperial Roman granite was quarried mainly in Egypt, and also in Turkey, and on the islands of Elba and Giglio . Granite became "an integral part of the Roman language of monumental architecture". The quarrying ceased around the third century AD. Beginning in Late Antiquity the granite was reused, which since at least

1748-434: Is called a binary or two-mica granite. Two-mica granites are typically high in potassium and low in plagioclase, and are usually S-type granites or A-type granites, as described below . Another aspect of granite classification is the ratios of metals that potentially form feldspars. Most granites have a composition such that almost all their aluminum and alkali metals (sodium and potassium) are combined as feldspar. This

1824-433: Is limited by the amount of thermal energy available, which must be replenished by crystallization of higher-melting minerals in the magma. Thus, the magma is melting crustal rock at its roof while simultaneously crystallizing at its base. This results in steady contamination with crustal material as the magma rises. This may not be evident in the major and minor element chemistry, since the minerals most likely to crystallize at

1900-404: Is permeated by sheets and channels of light granitic rock (the leucosome ). The leucosome is interpreted as partial melt of a parent rock that has begun to separate from the remaining solid residue (the melanosome). If enough partial melt is produced, it will separate from the source rock, become more highly evolved through fractional crystallization during its ascent toward the surface, and become

1976-454: Is relieved when overlying material is removed by erosion or other processes. Chemical weathering of granite occurs when dilute carbonic acid , and other acids present in rain and soil waters, alter feldspar in a process called hydrolysis . As demonstrated in the following reaction, this causes potassium feldspar to form kaolinite , with potassium ions, bicarbonate, and silica in solution as byproducts. An end product of granite weathering

2052-411: Is some concern that some granite sold as countertops or building material may be hazardous to health. Dan Steck of St. Johns University has stated that approximately 5% of all granite is of concern, with the caveat that only a tiny percentage of the tens of thousands of granite slab types have been tested. Resources from national geological survey organizations are accessible online to assist in assessing

2128-479: Is that magma will rise through the crust as a single mass through buoyancy . As it rises, it heats the wall rocks , causing them to behave as a power-law fluid and thus flow around the intrusion allowing it to pass without major heat loss. This is entirely feasible in the warm, ductile lower crust where rocks are easily deformed, but runs into problems in the upper crust which is far colder and more brittle. Rocks there do not deform so easily: for magma to rise as

2204-410: Is the case when K 2 O + Na 2 O + CaO > Al 2 O 3 > K 2 O + Na 2 O. Such granites are described as normal or metaluminous . Granites in which there is not enough aluminum to combine with all the alkali oxides as feldspar (Al 2 O 3 < K 2 O + Na 2 O) are described as peralkaline , and they contain unusual sodium amphiboles such as riebeckite . Granites in which there

2280-459: Is typically orthoclase or microcline and is often perthitic . The plagioclase is typically sodium-rich oligoclase . Phenocrysts are usually alkali feldspar. Granitic rocks are classified according to the QAPF diagram for coarse grained plutonic rocks and are named according to the percentage of quartz , alkali feldspar ( orthoclase , sanidine , or microcline ) and plagioclase feldspar on

2356-428: Is uncommon, is classified simply as quartz-rich granitoid or, if composed almost entirely of quartz, as quartzolite . True granites are further classified by the percentage of their total feldspar that is alkali feldspar. Granites whose feldspar is 65% to 90% alkali feldspar are syenogranites , while the feldspar in monzogranite is 35% to 65% alkali feldspar. A granite containing both muscovite and biotite micas

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2432-482: The +15 System ) provides shelter and easy access to the surrounding buildings. The building was often called Red Square in its early years, a derisive reference to its primary occupant Petro-Canada , which was a federal Crown Corporation created under Prime Minister Pierre Trudeau's National Energy Program . Following the completion of the complex in 1984, one writer for the Calgary Herald described

2508-699: The 23rd tallest building in Canada and the 6th tallest skyscraper outside of Toronto , as of 2023. The west tower overtook the Calgary Tower as the tallest free-standing structure in Calgary from its completion in 1984, until being surpassed by the neighbouring Bow in 2010. The office towers encompass 158,000 m (1,700,000 sq ft) of rentable office space with the complex also containing 23,000 m (250,000 sq ft) of retail and underground parking area. A glass-enclosed walkway (part of

2584-570: The Manhattan borough of New York City, that in September 2011 became a site of protests by Occupy Wall Street . On October 11, 2011, Richard Clark, the company's CEO, sent a letter to NYC Police Commissioner Raymond Kelly requesting to "clear the park" as its use by Occupy Wall Street "violates the law, violates the rules of the Park, deprives the community of its rights of quiet enjoyment to

2660-673: The Montreal Maroons and Montreal Canadiens National Hockey League franchises; from 1935 to 1957, the company also owned the Canadiens. The company was acquired by Edper Investments in 1970. During the 1970s, when the company was known as Carena Properties, it expanded its business into commercial real estate. After the Montreal Forum closed, the Forum was sold to competitor Canderel Properties. In 1989, Carena acquired

2736-571: The A-Q-P half of the diagram. True granite (according to modern petrologic convention) contains between 20% and 60% quartz by volume, with 35% to 90% of the total feldspar consisting of alkali feldspar . Granitic rocks poorer in quartz are classified as syenites or monzonites , while granitic rocks dominated by plagioclase are classified as granodiorites or tonalites . Granitic rocks with over 90% alkali feldspar are classified as alkali feldspar granites . Granitic rock with more than 60% quartz, which

2812-747: The City of London and 16 properties encompassing 8 million SF in three major Australian cities. On Earth Day on April 22, 2010, the company was listed as one of Canada's "The Green 30" Organizations Based On Eco-Friendly Programs and Practices based on an employee poll. In 2011, Brookfield Properties divested its residential group consisting of Carma Developers and Brookfield Homes (Ontario) Ltd. to merge with Brookfield Homes Corporation to form Brookfield Residential Properties Inc. That same year, Brookfield Properties changed its name to Brookfield Office Properties to reflect its focus on commercial office properties. In 2013, Brookfield Office Properties Inc. became

2888-615: The European Union safety standards (section 4.1.1.1 of the National Health and Engineering study) and radon emission levels well below the average outdoor radon concentrations in the US. Granite and related marble industries are considered one of the oldest industries in the world, existing as far back as Ancient Egypt . Major modern exporters of granite include China, India, Italy, Brazil, Canada, Germany, Sweden, Spain and

2964-526: The German House of Arenberg . In May 1980, a $ 200-million design was proposed with an all-glass, three-tower design including a 25-storey tower to be completed in 1982 and a larger 50-storey tower completed later in 1983. The Calgary Planning Commission rejected the proposal in Fall 1980 as the site was not large enough for the density three towers would provide, and the all-glass design was not desirable for

3040-639: The Mohs hardness scale) , and tough. These properties have made granite a widespread construction stone throughout human history. The word "granite" comes from the Latin granum , a grain, in reference to the coarse-grained structure of such a completely crystalline rock. Granitic rocks mainly consist of feldspar , quartz , mica , and amphibole minerals , which form an interlocking, somewhat equigranular matrix of feldspar and quartz with scattered darker biotite mica and amphibole (often hornblende ) peppering

3116-718: The Toronto Stock Exchange as of June 10, 2014, and from the New York Stock Exchange on June 20, 2014. Brookfield Property Partners is now the sole owner of all of the issued and outstanding common shares of BPO. In January 2016, Brookfield Properties purchased KIC, along with KIC's Berlin office. On August 28, 2018, Brookfield Property Partners acquired Chicago-based real estate investment trust and shopping mall operator GGP Inc. (General Growth Properties), and merged its assets into Brookfield Properties, for $ 9 billion. Brookfield immediately sold

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3192-511: The United States. The Red Pyramid of Egypt ( c.  2590 BC ), named for the light crimson hue of its exposed limestone surfaces, is the third largest of Egyptian pyramids . Pyramid of Menkaure , likely dating 2510 BC, was constructed of limestone and granite blocks. The Great Pyramid of Giza (c. 2580 BC ) contains a huge granite sarcophagus fashioned of "Red Aswan Granite". The mostly ruined Black Pyramid dating from

3268-419: The base of the chamber are the same ones that would crystallize anyway, but crustal assimilation is detectable in isotope ratios. Heat loss to the country rock means that ascent by assimilation is limited to distance similar to the height of the magma chamber. Physical weathering occurs on a large scale in the form of exfoliation joints , which are the result of granite's expanding and fracturing as pressure

3344-418: The big difference in rheology between mafic and felsic magmas makes this process problematic in nature. Granitization is an old, and largely discounted, hypothesis that granite is formed in place through extreme metasomatism . The idea behind granitization was that fluids would supposedly bring in elements such as potassium, and remove others, such as calcium, to transform a metamorphic rock into granite. This

3420-476: The buildings as "a twin-towered, $ 200-million monument to socialism ", and later Premier Peter Lougheed would blame Petro-Canada and the two towers for the collapse of the Calgary real-estate boom, in part by flooding the market . Petro-Canada was privatized in 1991 under the Brian Mulroney government and acquired in 2009 by the complex's current namesake, Suncor Energy , which continues to operate

3496-399: The city. Subsequently, Petro-Canada purchased the air rights from the neighbouring Calgary Chamber of Commerce for $ 2.5 million and received approval for a granite-clad two-tower design with a density bonus option of four storeys on the smaller tower. Construction on the complex began on April 2, 1982. During construction, local controversy arose when no Canadian bids were received to supply

3572-542: The company as a subsidiary. Planning for the complex began in the late-1970s following the creation of Petro-Canada. Petro-Canada came to an agreement with the West German firm ARCI Inc. to jointly develop an ARCI-owned site in Calgary to host the Crown Corporation's new headquarters. ARCI Inc served as an investment corporation, which had purchased the site several years early, and continues to be owned by

3648-404: The division between S-type (produced by underplating) and I-type (produced by injection and differentiation) granites, discussed below. The composition and origin of any magma that differentiates into granite leave certain petrological evidence as to what the granite's parental rock was. The final texture and composition of a granite are generally distinctive as to its parental rock. For instance,

3724-473: The early 16th century became known as spolia . Through the process of case-hardening , granite becomes harder with age. The technology required to make tempered metal chisels was largely forgotten during the Middle Ages. As a result, Medieval stoneworkers were forced to use saws or emery to shorten ancient columns or hack them into discs. Giorgio Vasari noted in the 16th century that granite in quarries

3800-579: The first magma to enter solidifies and provides a form of insulation for later magma. These mechanisms can operate in tandem. For example, diapirs may continue to rise through the brittle upper crust through stoping , where the granite cracks the roof rocks, removing blocks of the overlying crust which then sink to the bottom of the diapir while the magma rises to take their place. This can occur as piecemeal stopping (stoping of small blocks of chamber roof), as cauldron subsidence (collapse of large blocks of chamber roof), or as roof foundering (complete collapse of

3876-713: The grotto is a highly regarded piece of Buddhist art , and along with the temple complex to which it belongs, Seokguram was added to the UNESCO World Heritage List in 1995. Rajaraja Chola I of the Chola Dynasty in South India built the world's first temple entirely of granite in the 11th century AD in Tanjore , India . The Brihadeeswarar Temple dedicated to Lord Shiva was built in 1010. The massive Gopuram (ornate, upper section of shrine)

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3952-703: The largest office landlord in Los Angeles after acquiring MPG Office Trust Inc.'s downtown portfolio. MPG had been one of Southern California's most prominent real estate developers and a longtime L.A. office tower owner. The MPG buildings they acquired include the Gas Company Tower , 777 Tower and the Wells Fargo Center on Bunker Hill . In June 2014, Brookfield Property Partners (BPY) completed their acquisition of Brookfield Office Properties (BPO). BPO common shares were de-listed from

4028-570: The lighter color minerals. Occasionally some individual crystals ( phenocrysts ) are larger than the groundmass , in which case the texture is known as porphyritic . A granitic rock with a porphyritic texture is known as a granite porphyry . Granitoid is a general, descriptive field term for lighter-colored, coarse-grained igneous rocks. Petrographic examination is required for identification of specific types of granitoids. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy . The alkali feldspar in granites

4104-474: The lower crust , rather than by decompression of mantle rock, as is the case with basaltic magmas. It has also been suggested that some granites found at convergent boundaries between tectonic plates , where oceanic crust subducts below continental crust, were formed from sediments subducted with the oceanic plate. The melted sediments would have produced magma intermediate in its silica content, which became further enriched in silica as it rose through

4180-729: The lower continental crust at high thermal gradients. This leads to significant extraction of hydrous felsic melts from granulite-facies resitites. A-type granites occur in the Koettlitz Glacier Alkaline Province in the Royal Society Range, Antarctica. The rhyolites of the Yellowstone Caldera are examples of volcanic equivalents of A-type granite. M-type granite was later proposed to cover those granites that were clearly sourced from crystallized mafic magmas, generally sourced from

4256-435: The magma is inevitable once enough magma has accumulated. However, the question of precisely how such large quantities of magma are able to shove aside country rock to make room for themselves (the room problem ) is still a matter of research. Two main mechanisms are thought to be important: Of these two mechanisms, Stokes diapirism has been favoured for many years in the absence of a reasonable alternative. The basic idea

4332-426: The magma. Other processes must produce these great volumes of felsic magma. One such process is injection of basaltic magma into the lower crust, followed by differentiation, which leaves any cumulates in the mantle. Another is heating of the lower crust by underplating basaltic magma, which produces felsic magma directly from crustal rock. The two processes produce different kinds of granites, which may be reflected in

4408-408: The magmatic parent of granitic rock. The residue of the source rock becomes a granulite . The partial melting of solid rocks requires high temperatures and the addition of water or other volatiles which lower the solidus temperature (temperature at which partial melting commences) of these rocks. It was long debated whether crustal thickening in orogens (mountain belts along convergent boundaries )

4484-456: The management of Forest City Realty Trust 's real estate portfolio after the company was acquired by a fund affiliated with Brookfield Asset Management. In September 2020, the company's retail group announced a layoff of 20% of its workforce of about 2,000 people. Around June 2021, the company opened an office in Sydney, Australia. In May 2023, Brookfield Properties announced a purchase of

4560-405: The mantle. Although the fractional crystallisation of basaltic melts can yield small amounts of granites, which are sometimes found in island arcs, such granites must occur together with large amounts of basaltic rocks. H-type granites were suggested for hybrid granites, which were hypothesized to form by mixing between mafic and felsic from different sources, such as M-type and S-type. However,

4636-441: The overlying crust. Early fractional crystallisation serves to reduce a melt in magnesium and chromium, and enrich the melt in iron, sodium, potassium, aluminum, and silicon. Further fractionation reduces the content of iron, calcium, and titanium. This is reflected in the high content of alkali feldspar and quartz in granite. The presence of granitic rock in island arcs shows that fractional crystallization alone can convert

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4712-736: The reign of Amenemhat III once had a polished granite pyramidion or capstone, which is now on display in the main hall of the Egyptian Museum in Cairo (see Dahshur ). Other uses in Ancient Egypt include columns , door lintels , sills , jambs , and wall and floor veneer. How the Egyptians worked the solid granite is still a matter of debate. Tool marks described by the Egyptologist Anna Serotta indicate

4788-420: The relative percentages of quartz, alkali feldspar, and plagioclase (the QAPF classification ), with true granite representing granitic rocks rich in quartz and alkali feldspar. Most granitic rocks also contain mica or amphibole minerals, though a few (known as leucogranites ) contain almost no dark minerals. Granite is nearly always massive (lacking any internal structures), hard (falling between 6 and 7 on

4864-564: The risk factors in granite country and design rules relating, in particular, to preventing accumulation of radon gas in enclosed basements and dwellings. A study of granite countertops was done (initiated and paid for by the Marble Institute of America) in November 2008 by National Health and Engineering Inc. of USA. In this test, all of the 39 full-size granite slabs that were measured for the study showed radiation levels well below

4940-418: The rock's high quartz content and dearth of available bases, with the base-poor status predisposing the soil to acidification and podzolization in cool humid climates as the weather-resistant quartz yields much sand. Feldspars also weather slowly in cool climes, allowing sand to dominate the fine-earth fraction. In warm humid regions, the weathering of feldspar as described above is accelerated so as to allow

5016-414: The rocks often bear a close resemblance. Under these conditions, granitic melts can be produced in place through the partial melting of metamorphic rocks by extracting melt-mobile elements such as potassium and silicon into the melts but leaving others such as calcium and iron in granulite residues. This may be the origin of migmatites . A migmatite consists of dark, refractory rock (the melanosome ) that

5092-492: The roof of a shallow magma chamber accompanied by a caldera eruption.) There is evidence for cauldron subsidence at the Mt. Ascutney intrusion in eastern Vermont. Evidence for piecemeal stoping is found in intrusions that are rimmed with igneous breccia containing fragments of country rock. Assimilation is another mechanism of ascent, where the granite melts its way up into the crust and removes overlying material in this way. This

5168-533: The site with exterior granite cladding, which resulted in the use of $ 500,000 of Finnish granite, which was cut and polished in Italy and shipped to the Calgary site for installation. Another local controversy was the installation of bilingual signage (French and English), which Petro-Canada head office insisted upon. On January 4, 1983, the West tower reached 191 metres in height, exceeding the Calgary Tower and becoming

5244-435: The surface than magmas of I-type granites, which are thus more common as volcanic rock (rhyolite). They are also orogenic but range from metaluminous to strongly peraluminous. Although both I- and S-type granites are orogenic, I-type granites are more common close to the convergent boundary than S-type. This is attributed to thicker crust further from the boundary, which results in more crustal melting. A-type granites show

5320-556: The tallest freestanding structure in Calgary and Western Canada . The 52-storey west tower was topped off on May 26, 1983, and the complex was completed in 1984. During construction in April 1983, one of the site's tower cranes collapsed, killing its operator. In December 1998, Petro-Canada sold their remaining half interest in the complex to Gentra Inc. (former subsidiary of Brookfield Properties ) for $ 200 million (equivalent to $ 344 million in 2023), which included Petro-Canada signing

5396-502: The uranium washes into the sediments from the granite uplands and associated, often highly radioactive pegmatites. Cellars and basements built into soils over granite can become a trap for radon gas, which is formed by the decay of uranium. Radon gas poses significant health concerns and is the number two cause of lung cancer in the US behind smoking. Thorium occurs in all granites. Conway granite has been noted for its relatively high thorium concentration of 56±6 ppm. There

5472-617: The use of flint tools on finer work with harder stones, e.g. when producing the hieroglyphic inscriptions. Patrick Hunt has postulated that the Egyptians used emery , which has greater hardness. The Seokguram Grotto in Korea is a Buddhist shrine and part of the Bulguksa temple complex. Completed in 774 AD, it is an artificial grotto constructed entirely of granite. The main Buddha of

5548-722: The world, including China, India, Germany and the US. The company's roots go back to the early 1900s in Montreal, Quebec . It was known then as the Canadian Arena Company and operated the Montreal Arena . In a partnership with Toronto investors, it built Arena Gardens in Toronto. In the 1910s, it opened an office and began business in Brazil, while in the 1920s, it built the Montreal Forum to house

5624-464: Was "far softer and easier to work than after it has lain exposed" while ancient columns, because of their "hardness and solidity have nothing to fear from fire or sword, and time itself, that drives everything to ruin, not only has not destroyed them but has not even altered their colour." Brookfield Properties Brookfield Properties is a North American subsidiary of commercial real estate company Brookfield Property Partners , which itself

5700-405: Was sufficient to produce granite melts by radiogenic heating , but recent work suggests that this is not a viable mechanism. In-situ granitization requires heating by the asthenospheric mantle or by underplating with mantle-derived magmas. Granite magmas have a density of 2.4 Mg/m , much less than the 2.8 Mg/m of high-grade metamorphic rock. This gives them tremendous buoyancy, so that ascent of

5776-564: Was supposed to occur across a migrating front. However, experimental work had established by the 1960s that granites were of igneous origin. The mineralogical and chemical features of granite can be explained only by crystal-liquid phase relations, showing that there must have been at least enough melting to mobilize the magma. However, at sufficiently deep crustal levels, the distinction between metamorphism and crustal melting itself becomes vague. Conditions for crystallization of liquid magma are close enough to those of high-grade metamorphism that

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