But rapakivi granites are more than just building material, they have also been studied scientifically for over 100 years to try to explain the formation of their plagioclase. Baltic brown is an excellent example of a stone with combination of durable. If this is the first time you use this feature, you will be asked to authorise cambridge core to connect with your account. Shaped eons ago, baltic brown granite resists weather conditions, wear, freeze and thaw. Pdf petrogenetic and mineralization processes in paleo.
In literature the word rapakivi can be found as early as 1694 ac and the rapakivi granite was described in international geological literature in 1891 by j. Commonly they are potash feldspar often mantled by, and having a variable content of. In the palaeoproterozoic ketilidian orogen of south greenland, tabular intrusions of the rapakivi granite suite exposed at graah fjelde, lindenow fjord and qernertoq, and a mesoproterozoic syenite of the gardar province exposed at paatusoq, were emplaced by a. Rapakivi is finnish for crumbly rock, because the different heat expansion coefficients of the component. A field guide to the proterozoic anorthositic, monzonitic, and granitic plutons, laramie range southeastern wyoming. More specifically a rock having an alkalifeldspartotal feldspar ratio from 0. These keywords were added by machine and not by the authors. Rapakivi granites and several small leucogabbroic and gabbroic bodies are located in the rangnim massif, north korea. Clinopyroxene episyenites in a proterozoic rapakivi.
Rapakivi granite, anorthosite and charnockitic plutonism nature. A notable example of a volcanic body with rapakivi texture is a miocene rhyolite 2 that has an exposure area of about 116 square mile. Search for library items search for lists search for. Typical rapakivi texture is a mixture of variously mantled, nonmantled or partly mantled, concentrically zoned, plastically distorted, fragmented, reaggregated, large and small ovoids. Magmatic evolution of topazbearing granite stocks within. These flat, sheetlike, proterozoic intrusions are considered by. This stone internationally may be nominated as a granite and in the area of application of the european standard this stone must be nominated as granite. Of960406 a field guide to the proterozoic anorthositic.
Baltic brown sd rapakivi granite the baltic brown is being quarried in luumaki area, southeastern finland. Posttectonicofanorogenic rapakivi granite and anorthosite ofmidprotero zoic age are scattered in an are across the northern hemisphere from the ural mountains to western north america. Rapakivi granites in the southern death valley region, california, include the 12. One hundred years of rapakivi granite springerlink. The occurrence and geochemistry of fluorides in natural. Discovery of paleoproterozoic rapakivi granite on the northern. Karelia red a rapakivi granite the karelia red is being quarried in virolahti area, southeastern finland. The country rocks of rapakivi granites are neoarchaean. Assimilation water vapor pressure alkali feldspar rapakivi granite hydrothermal experiment. Rbsrstudy of rapakivi granite and augen gneiss of the.
First scientific study about rapakivi granite is a thesis of the j. Rapakivi granite is a hornblendebiotite granite containing large round crystals of orthoclase each with a rim of oligoclase. Miarolitic pegmatites of the viborg rapakivi granite. The study was performed as field mapping, comprising the whole batholith and as detailed investigations on selected outcrops. The lincoln granite occupies much of the area directly south of the summit of the sherman mountains, where it crops out as subhorizontal sheets. Rapakivi granites, recently redefined as atype granites showing rapakivi texture at least in the larger batholiths, occur on all continents and presumably represent the most voluminous continental silicic intraplate magmatism on earth. The lithology of the batholith is diverse, but most of it comprises wiborgite, the rapakivi granite proper see vorma,1976. The name rapakivi is given to this granite due to its crumbly structure as it has variable heat expansion coefficient. Once the similarities between cenozoic topaz rhyolites and proterozoic rapakivi granites are clear, we consider a new model for the origin of topaz rhyolites and its implications for the petrogenesis of rapakivi granites in particular and atype granites in general. Rapakivi granites have puzzled all who have seriously studied them. Gc47m2b rapakivi, rapakivigranite earthcache in finland. A link between anorthosite and rapakivi granite 6 has been proposed, rapakivi granite being a high level crystallisation related to and contemporaneous with anorthosite emplacement at greater depth. The layering at this locality is unusual in that it is defined by interstitial phases.
Reebearing minerals in the rapakavi grante, southern. Evidence for a late devonian posttectonic cryptic silicicmafic magma chamber. North of the sherman mountains, the lincoln granite caps hills and knolls. Mafic minerals are biotite mica and amphibole, plus some quartz. Rapakivi a granite of porphyroid structure with round phenocrysts of pink orthoclase surrounded by a white or light green shell of oligoclase. Rapakivi granite article about rapakivi granite by the free. Rapakivi texture from the oleary porphyry, arizona u. The density of baltic brown makes it stain, water and mildew resistant. Here, we describe the occurrence of rapakivi feldspars in atype granites from the malani igneous suite in western india and use microtextural and geochemical evidence to argue that rapakivi textures can form by subsolidus deuteric alteration of feldspar megacrysts through a coupled dissolutionreprecipitation replacement process. The fields for the calcalkaline and finnish rapakivi granites are from frost et al.
Emplacement and magnetic fabrics of rapakivi granite. This unique red stone has a long tradition worldwide and the quarrying history extends over the centuries. Granites and rhyolites with high k contents and extreme fe enrichment are a distinctive rock type of problematic origin that are found throughout the proterozoic anorogenic granite provinces of the southwestern usa, adirondacks, eastern canada, southern greenland and the fennoscandian shield anderson, 1983. Many of the newer observations are inconsistent with the earlier theory. In the ussr it is found in the karelian assr, in leningrad oblast near the city of vyborg, and in the ukraine near the village of gorodishche in cherkassy oblast. Oppdal rapakivi granite, and these rocks fit an interesting global pattern. Origin of rapakivi feldspar by a fluidinduced coupled. The megacrysts are almost free of orthoclaserich patches and veins close to the boundary. Phanerozoic examples include paleozoic granites of. This unique red stone has a long tradition worldwide and. Rapakivi granite article about rapakivi granite by the. Natural stone production in the wiborg rapakivi granite.
Reduced rapakivitype granites are the most iron enriched and reduced i. Emplacement of rapakivi granite and syenite by floor. Geochemical studies show that the rapakivi granites and associated rocks form metaluminous to peraluminous atype granites and plot in the within plate granites wpg field on the tectonic discriminate diagrams from the onkamaa, suomenniemi and luumaki. Rapakivi is finnish for crumbly rock, because the different heat expansion coefficients of the component minerals make exposed rapakivi crumbly. The name has come to be used most as a textural term where it implies plagioclase rims around orthoclase in plutonic rocks. The word rapakivi is finnish that means crumbly rock. The 16501540 ma rapakivi granites and associated basic rocks e.
Weighing 1,250 tonnes, this boulder is claimed to be the largest stone moved by humans. On the surface of the bedrock outcrop you can see a beautiful salmon redgray pattern that resembles a fingerprint. All of these granitic rocks are texturally zoned from a porphyritic rim facies, characterized by rapakivi textures and miarolitic cavities, to an equigranular aplite. The word granite comes from the latin granum, a grain, in reference to the coarsegrained structure of such a completely crystalline rock. Im a special form of a granite rock called, rapakivi granite. Rapakivigranite on aland finland version 1 erich spicar lorensbergavagen 2b s771 42 ludvika erich. Rapakivi granite, anorthosite and charnockitic plutonism. Upb zircon age dating of a rapakivi granite batholith in. Reduced rapakivi type granites are the most iron enriched and reduced i.
Rapakivi granites muller 2007 geology today wiley online. Gc18bj9 graniitti, gneissi, rapakivi earthcache in. In 1770 a rapakivi granite monolith boulder, the thunder stone, was used as the pedestal for the bronze horseman statue in saint petersburg, russia. Ascent of felsic magmas and formation of rapakivi hann. Media in category rapakivi granite the following 31 files are in this category, out of 31 total.
Magmatic evolution of topazbearing granite stocks within the wiborg rapakivi granite batholith, university of helsinki, 2007, 29 pp. The anorthositemangeritecharnockite rapakivi granite magmatic series associated with this magmatism originated in backarc settings, if we consider the latter in a broad sense as corresponding to the rear parts of peripheral orogens whose evolution lasted from. The discovery of paleoproterozoic huashanguan rapakivi granites indicates. The gaborone granite complex botswana, southern africa.
November 8, 2005 granites continued, rapakivi texture bowens argument. Igneous layering is developed in the proterozoic rapakivi granite suite of south greenland in an area on the southeasternmost coast of the island of angnikitsoq. Sorption and desorption of cesium on rapakivi granite and. The name has come to be used most frequently as a textural term where it implies plagioclase rims around orthoclase in plutonic rocks. Pdf rapakivi granites characteristic practically of all old platforms are greatly variable in age and. Pdf rapakivi granites in the geological history of the earth. Petrology lab course without a real microscope just isnt the same. The studied rock samples belong to the classic 16151645 ma wiborg rapakivi granite terrane of southeastern finland. The mineralogy and chemistry of these feldspars has been reinvestigated optically and with an electron microprobe. The anorthositemangeritecharnockiterapakivi granite magmatic series associated with this magmatism originated in backarc settings, if we consider the latter in a broad sense as corresponding to the rear parts of peripheral orogens whose evolution lasted from.
Rapakivi granite is a hornblendebiotite granite containing large round crystals of orthoclase each with a rim of oligoclase a variety of plagioclase. The aeromagnetic images of rapakivi granite batholiths in finland show that the rapakivi granite batholiths are built up of several intrusions of distinct shapes. Request pdf rapakivi granites rapakivi granites, especially the famous rapakivis from southern finland, are some of the most attractive building and decorative stones, used. Rapakivi article about rapakivi by the free dictionary. Petrology, age, and tectonic setting of the rapakivi. Clear, nonmetamict and inclusionfree zircon grains were. Pdf implications of surface weathering of rapakivi granite outcrops for natural stone evaluation were studied in the. The age of the sandstone is probably 1200 million years. Geology in short the viborg rapakivi granite covers large areas ofse finland and consists ofseveral varieties of granite. A coarsegrained, holocrystalline, felsic, acidic, plutonic rock. Surface weathering of rapakivi granite outcrops implications for natural stone exploration and quality evaluationrabakivi graniidi paljandite pindmise murenemise tahendus loodusliku kivi uuringutel ja kvaliteedi hindamisel. Rapakivi granites, especially the famous rapakivis from southern finland, are some of the most attractive building and decorative stones, used. A new rocktype was born, rapakivi granite, which was described almost 1600 million years later and at first time in finland. Geochemistry and origin of the early mesoproterozoic mangeritecharnockite rapakivi granite association of the serra da providencia suite and associated gabbros, centraleastern rondonia, sw amazonian craton, brazil.
The low oxygen fugacity and chemical composition of these granites severely limit their sources. The finnish bedrock is formed over millions of years. Earth sciences science and technology, general rocks identification and classification. A granitoid a coarsegrained igneous rock composed mostly of quartz, kfeldspar alkalifeldspar and plagioclase. Born in the inner fires of the earth, baltic brown granite is basically unfazed by flames and heat. Rapakivi is the material used in alands mediaeval stone churches. Reebearing minerals in the rapakavi grante, southern finland. Rapakivi granites have intruded into svecokarelian granitoids, gneisses, schists and metavolcanites lahti 1993. A term, used as both an adjective and noun, for a variety of granite usually containing amphibole and biotite and characterized by the presence of large oval grains ovoids of orthoclase which are usually mantled by plagioclase. Pdf rapakivi granites in the geological history of the. Natural stone exploration in the classic wiborg rapakivi. We suggest that largescale hydrothermal alteration has converted a finegrained pyroxene cumulate, in which original cumulate pyroxenes occurred. Known for its striking texture in hand samples, with large roundoval pink orthoclase feldspars surrounded by a rim of clear albite rich plagioclase. Most of the rapakivi granites are proterozoic mainly 1.
A thin section microscope slide of rapakivi granite from finland. Baltic brown granite is a tremendously dense and tough stone. Granitoids of these asso ciations used to be divided into the following three groups. Rapakivi texture has rarely been reported in volcanic rocks 1. Pdf surface weathering of rapakivi granite outcrops implications. Are cenozoic topaz rhyolites the erupted equivalents of. Aug 28, 2012 rapakivi granite is considered in the class of hornblende biotite granite that is found rich in orthoclase and oligoclase.
Granites can be predominantly white, pink, or gray in color, depending on their mineralogy. Pdf geochemistry and origin of the early mesoproterozoic. A link between anorthosite and rapakivi granite 6 has been proposed, rapakivi granite being a high level crystallisation related to and contemporaneous. The granite also occurs as dikes, in which it is locally commingled with monzodiorite. Origin of rapakivi feldspar by a fluidinduced coupled dissolution. Wiborg rapakivi granite batholith kymi stock biotite rapakivi granite evengrained rapakivi granite wiborgite pyterlite porphyritic rapakivi granite aplitic rapakivi granite gabbro, anorthosite dark wiborgite svecofennian rocks 1. Baltic brown has a long history within the stone industry and is wellknown all over the world. Discussion on emplacement of rapakivi granite and syenite. Miocene rapakivi granites in the southern death valley. Jun 25, 2007 rapakivi granites, especially the famous rapakivis from southern finland, are some of the most attractive building and decorative stones, used world. Pdf 4488 k pdf plus 4490 k petrology, age, and tectonic setting of the rapakivi bearing margaree pluton, cape breton island, canada. The mantling is older than the brecciation and independent of it. The largest batholith in the myohyang mountains covers an area of 300 km 2 and was intruded into precambrian metamorphosed rocks. The wiborg batholith is composed of wiborgite, pyterlite, evengrained rapakivi granite, porphyritic rapakivi granite, porphyry aplite, and gabbroanorthosite.
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