Rapakivi granites, especially the famous rapakivis from southern finland, are some of the most attractive building and decorative stones, used worldwide because of. It is composed of several petrographically and geochemically distinct granite types. Shaped eons ago, baltic brown granite resists weather conditions, wear, freeze and thaw. 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. 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 combination of roof uplift and floor depression. Geology and age of the parguaza rapakivi granite, venezuela. Nomenclature of plutonic rocks plotted on the qap diagram. Rapakivi granite, anorthosite and charnockitic plutonism nature.
Typical wiborgite and pyterlite are found in the rondonia and roraima regions in brazil and in venezuela parguaza granite. The suomenniemi batholith thus represents an early magmatic precursor to the classic wiborg batholith and was. May 01, 2007 rapakivi granite is not an official classification of granite and does not have its own field in these diagrams. Magmatic evolution of topazbearing granite stocks within the wiborg rapakivi granite batholith, university of helsinki, 2007, 29 pp.
The finnish rapakivi granite batholiths consist of several granite types with smaller bodies of anorthositic or gabbroic bodies. November 8, 2005 granites continued, rapakivi texture bowens argument. Magmatic evolution of topazbearing granite stocks within. Jack creek rapakivi granite 1465 ma porphyritic granite 14401460 ma minette 1465 ma burro mountain granite yg of hedlund 1980a, b 14401460 ma bullard peak and ash creek metamorphic rocks 1633, 15501570 ma quartzofeldspathic gneiss granulite of hedlund 1980a. Granite magmatism and extensional tectonics in southern. Emplacement of rapakivi granite and syenite by floor. Rapakivi texture has rarely been reported in volcanic rocks1.
Wed like to understand how you use our websites in order to improve them. The occurrence and geochemistry of fluorides in natural. Table 1 shows the available relevant and accurate data. Most of the rapakivi granites are proterozoic mainly 1. The layering at this locality is unusual in that it is defined by interstitial phases. Baltic brown has a long history within the stone industry and is wellknown all over the world. Reduced rapakivi type granites are the most iron enriched and reduced i.
The name has come to be used most frequently as a textural term where it implies plagioclase rims around orthoclase in plutonic rocks. Pdf 4488 k pdf plus 4490 k petrology, age, and tectonic setting of the rapakivi bearing margaree pluton, cape breton island, canada. 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. On the eastern side of the batholith is the satellitic uljalegi rapakivi granite pluton. Petrogenetic and mineralization processes in paleo to mesoproterozoic rapakivi granites. 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. Pdf rapakivi granites characteristic practically of all old platforms are greatly variable in age and irregularly. The general picture is thus similar to that observed in the amcg suites of north america, differing in some degree from the classic finnish rapakivi. 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.
Geochronological, petrological and geochemical aspects. 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. While the produced granite is sound and intact, a typical feature of rapakivi granite is the distinct surface weathering of outcrops, socalled. Rapakivi granites and several small leucogabbroic and gabbroic bodies are located in the rangnim massif, north korea. The lithology of the batholith is diverse, but most of it comprises wiborgite, the rapakivi granite proper see vorma,1976. Rapakivi granite a granite with feldspars of orthoclase. 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. 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.
The word rapakivi is finnish that means crumbly rock. Baltic brown is an excellent example of a stone with combination of durable. Rapakivi granite, anorthosite and charnockitic plutonism. Ascent of felsic magmas and formation of rapakivi hann. Rapakivi is finnish for crumbly rock, because the different heat expansion coefficients of the component minerals make exposed rapakivi. Full analytical results and details and sem images of the analysed grains with spatial information on both methods are available at. Geochemistry and origin of early proterozoic dongargarh.
The age of the sandstone is probably 1200 million years. Media in category rapakivi granite the following 31 files are in this category, out of 31 total. In some areas, the rock surface was strongly weathered, forming a gravel like surface. Isotopic composition of pyterlite in vyborg viipuri, wiborg batholith, russia. Natural stone exploration in the classic wiborg rapakivi.
Are cenozoic topaz rhyolites the erupted equivalents of. Pdf 4488 k pdf plus 4490 k petrology, age, and tectonic setting of the rapakivibearing margaree pluton, cape breton island, canada. Map showing the localities of the topazbearing granite stocks in the wiborg rapakivi granite batholith and its satellites, and lithologic maps from a the artjarvi granite stock and b the saaskjarvi granite stock. A rapakivi granite associated with the anorthositic rocks has different isotope composition. Discussion on emplacement of rapakivi granite and syenite. Rapakivi texture article about rapakivi texture by the. These flat, sheetlike, proterozoic intrusions are considered by.
Rapakivi is finnish for crumbly rock, because the different heat expansion coefficients of the component. We suggest that largescale hydrothermal alteration has converted a finegrained pyroxene cumulate, in which original. A notable example of a volcanic body with rapakivi texture is a miocene rhyolite2 that has an exposure area of about 116 square mile. Discovery of paleoproterozoic rapakivi granite on the.
The density of baltic brown makes it stain, water and mildew resistant. Rapakivi granite is part of wikiproject rocks and minerals, an attempt at creating a standardized, informative, comprehensive and easytouse rocks and minerals resource. The source of proterozoic anorthosite and rapakivi granite. Rapakivi series are widespread in the amazonian craton and show ages between 1. The oldest granites have been found in the eastern amazonian region, where. Rapakivi granites from brazil and adjacent areas sciencedirect. 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. Karelia red a rapakivi granite the karelia red is being quarried in virolahti area, southeastern finland. 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. Rapakivi a granite of porphyroid structure with round phenocrysts of pink orthoclase surrounded by a white or light green shell of oligoclase. Born in the inner fires of the earth, baltic brown granite is basically unfazed by flames and heat. The salmi rapakivi graniteanorthosite batholith is situated at the contact between the archean granite gneissgreenstone belt basement and paleoproterozoic svecofennian orogenic belt. Baltic brown sd rapakivi granite the baltic brown is being quarried in luumaki area, southeastern finland. Clinopyroxene episyenites in a proterozoic rapakivi.
Known for its striking texture in hand samples, with large roundoval pink orthoclase feldspars surrounded by a rim of clear albite rich plagioclase. Rapakivi texture article about rapakivi texture by the free. Upb zircon age dating of a rapakivi granite batholith in. The eurajoki stock is a satellite of the laitila rapakivi granite batholith. Weighing 1,250 tonnes, this boulder is claimed to be the largest stone moved by humans. The name has come to be used most as a textural term where it implies plagioclase rims around orthoclase in plutonic rocks. Miarolitic pegmatites of the viborg rapakivi granite. Of960406 a field guide to the proterozoic anorthositic. Surface weathering of rapakivi granite outcrops implications for natural stone exploration and quality evaluation. The largest batholith in the myohyang mountains covers an area of 300 km 2 and was intruded into precambrian metamorphosed rocks. Bulletin of the geological society of finland 73, parts 12, 111115. Reduced rapakivitype granites are the most iron enriched and reduced i. If you would like to participate, you can choose to edit this article, or visit the project page for more information.
Rapakivi is finnish for crumbly rock, because the different heat expansion coefficients of the. Being anorogenic and not deformed, rapakivi granites are highly potential for natural stone, and the demand for new stone qualities from the rapakivi areas is continuous. Natural stone production in the wiborg rapakivi granite. The oldest granites have been found in the eastern amazonian region, where the ages of several complexes. Source constraints from the hf isotope composition of zircon in the rapakivi granites and associated mafic rocks of southern finland a. Chemical analyses of rapakivi granites plot in the granite field of the qap diagram and some in the granodiorite and quartz monzonite field of the tas diagram fig. Hawkes j 1967 rapakivi texture in the dartmoor granite. 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 vehmaa rapakivi granite batholith in southwestern finland. Baltic brown granite is a tremendously dense and tough stone. Rapakivi granite article about rapakivi granite by the free. Aug 28, 2012 rapakivi granite is considered in the class of hornblende biotite granite that is found rich in orthoclase and oligoclase.
Find premium, highresolution stock photography at getty images. Evidence for a late devonian posttectonic cryptic silicicmafic magma chamber. Petrology, age, and tectonic setting of the rapakivibearing. Pdf on jan 1, 1977, ilmari haapala and others published petrography and geochemistry of the eurajoki stock.
The country rocks of these rapakivi granite batholiths are also comparable. 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. Rapakivi granite article about rapakivi granite by the. The name rapakivi is given to this granite due to its crumbly structure as it has variable heat expansion coefficient. The word granite comes from the latin granum, a grain, in reference to the coarsegrained structure of such a completely crystalline rock. The next event to strongly reshape the finnish bedrock was the emplacement of the rapakivi granites. One hundred years of rapakivi granite springerlink. Rapakivi granite is a hornblendebiotite granite containing large round crystals of orthoclase each with a rim of oligoclase a variety of plagioclase.
Several rapakivi complexes contain topazbearing latestage intrusive phases which are often associated with greisentype snwbezn mineralization. These stones are coarsegrained rocks with a typical rapakivi texture of large round kfeldspar ovoids, with or without a plagioclase rim. Mafic minerals are biotite mica and amphibole, plus some quartz. Several episodes of granite magmatism are recorded, culminating in the late. Rapakivi granite is a hornblendebiotite granite containing large round crystals of orthoclase each with a rim of oligoclase. The 165154 ga rapakivi granites of southeastern fennoscandia represent the silicic members of a bimodal magmatic association in which the mafic members.
Pdf rapakivi granites in the geological history of the earth. These geochemical characteristics of the huashanguan granites were concor dant with typical rapakivi granites, and had an affinity to atype granites. Geochronological data about the amazonian craton rapakivi magmatism were summarized by dallagnol et al. Contact relations between the later and the rapakivi granite su9gests the rapakivi granites to be younger ramo et al. Pdf geochemistry and origin of the early mesoproterozoic. Rapakivi is the material used in alands mediaeval stone churches.
Tectonic setting and origin of the proterozoic rapakivi granites of. The finnish bedrock is formed over millions of years. Magmatic and postmagmatic processes in tinmineralized. The batholith is approximately 85 km long, 35 km wide, and 10 km thick. Pdf petrogenetic and mineralization processes in paleo. The studied rock samples belong to the classic 16151645 ma wiborg rapakivi granite terrane of southeastern finland. Granites can be predominantly white, pink, or gray in color, depending on their mineralogy.
View topquality stock photos of rapakivi granite a granite with feldspars of orthoclase cores oligoclase and plagioclase rims note the zoning in the feldspars the penny is used for scale usa. A thin section microscope slide of rapakivi granite from finland. Petrology, age, and tectonic setting of the rapakivi. A field guide to the proterozoic anorthositic, monzonitic, and granitic plutons, laramie range southeastern wyoming. In 1770 a rapakivi granite monolith boulder, the thunder stone, was used as the pedestal for the bronze horseman statue in saint petersburg, russia. Rapakivi granites in the geological history of the earth. Pdf rapakivi granites in the geological history of the. Shrimp zircon age of a proterozoic rapakivi granite. The massive rapakivi granite intrudes foliated granitic rocks and associated volcanic rocks of transamazonian age in a structural setting transcurrent to the general. Heinonen 1 department of geology, po box 64, fin00014, university of helsinki, helsinki, finland. Reebearing minerals in the rapakavi grante, southern. Qap plot of modal compositions of the palaeoproterozoic anorogenic rapakivi granites of the. In other regions, medium, evengrained granites are largely dominant. The magma mixing origin of mantled feldspars springerlink.
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. Rapakivi granites, especially the famous rapakivis from southern finland, are some of the most attractive building and decorative stones, used worldwide because of their striking textures and. The low oxygen fugacity and chemical composition of these granites severely limit their sources. This unique red stone has a long tradition worldwide and the quarrying history extends over the centuries. Origin of rapakivi feldspar by a fluidinduced coupled. Pdf surface weathering of rapakivi granite outcrops. Geochronology of the suomenniemi rapakivi granite complex.
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