At gggsc, we apply expertise in geology, geophysics, and geochemistry to interdisciplinary efforts in support of the usgs mission to address the nations important earth science issues, with an emphasis on mineral resources. These result in i type granitoids, derived from igneous protoliths and containing moderate amounts of al2o3 and high amounts of na2o, and s type granitoids, derived from sedimentary protoliths and containing high amounts of al2o3 and relatively low amounts of na2o. Geochemistry and petrogenesis of s type granites in the. Understanding the geochemistry of oil and gas reserves, from wellbore to basin. This geochemical classification of granitic rocks is based upon three variables. Since the pioneering works by maack 1953 and trein 1967, who introduced the term morro redondo granite in literature, several authors have contributed to the geology, structure, petrography, geochemistry and geochronology knowledge on the granitic and volcanic rocks constituted therein e.
The a type geochemical signature, a sourcerelated characteristic, probably derives from a crustal protolith from which i type granitic melts had been previously extracted. The precambrian sandia granite of northcentral new mexico belongs to the 1. Granites of both age groups appear to have been formed by anatexis of krummedal. Geochemically, the nakora granites are peralkaline, metaluminous and slightly peraluminous. Zircon upb geochronology, wholerock geochemistry and. This complex consists of three phases volcanic, plutonic and dyke. Geochemical plotting programs this site contains a compilation of geochemical plotting programs compiled by sumit chakraborty, ruhruniversitat bochum, with input from colleagues on the mineralogical society of america email list. Data reduction was conducted using the isoplotex v. Geochronological and geochemical constraints on the. Plane polarized light photomicrograph showing garnet and biotite in sample cv126 from the mafic s type strathbogie granite, australia. As can be observed in table 3, biotite granite samples display variable composition, but on harker type diagrams, there is a linear decrease in tio 2, fe 2 o 3 t, al 2 o 3, mno, cao, and p 2 o 5, and an increase in k 2 o and k 2 ona 2 o with increasing silica.
Geochemical data toolkit gcdkit is a program for handling and recalculation of geochemical data from igneous and metamorphic rocks. White2 1arc key centre for the geochemistry and metallogeny of the continents gemoc, department of earth. Itype are dominantly magnesian, but, like the mesozoic batholiths of western north america fig. In the eastern hegenshanheihe suture zone hhsz of ne china, cuau hydrothermal mineralization at the newly discovered hongyan deposit is associated with the shanshenfu alkalifeldspar granite safg. In the conterminous united states, ages of atype granitoid rocks are restricted to the period between. Geochemistry of stype granitic rocks from the reversely zoned castelo branco pluton central portugal i. Geochemical characteristics of atype granite near the. Zeigler 1department of earth and planetary sciences and the mcdonnell center for space sciences, washington university, st. Granite the term granite is derived from latin word granum. Opaque mineralogy and mafic mineral chemistry of i and s. Interpretation of wholerock geochemical data in igneous.
Amphibole and pyroxene are more common in itype granitoids. You may, without any fee or cost, use, copy, modify. Good discrimination can be obtained between a type granites and most orogenic granites m, i and stypes on plots employing gaal, various major element ratios and y, ce, nb and zr. Geology, petrography and geochemistry of the atype granites. Stype granites are rich in biotite, but their origin has been not resolved yet. By comparing the wholerock geochemistry of typical itype and s type granites from lachlan fold belt lfb in southeast australia, chappell 1999 found that the two types of granite can be well. Geology, petrography and geochemistry of the atype. Biotite compositions from s type granites are more aluminous than those of i type granites consistent with the higher asi index of s type granites. To address geochemical analysis on a basin scale, petromod petroleum systems modeling software lets you assess source rock maturity, hydrocarbon migration, and the associated properties of oil and gas. Mineralogy and geochemistry of anorogenic granitic. The atype granites form in an extensional tectonic setting. Apatite in the itype granite samples yields f and cl concentrations of 6002600 ppm and below the detection limit to 600 ppm.
Some earth science data, such as geochemical measurements of element concentrations, are nonstationarythe mean and the standard deviation vary spatially. The taihua complex, in the transnorth china orogen fig. The nakora ring complex nrc 732 ma occurs as a part of malani igneous suite mis in the western rajasthan, india. Atype granite charnockitic rocks hydrated charnockite archean carajas amazonian craton new wholerock geochemistry and lamcicpms and pbevaporation geochronological data were obtained on zircon from the neoarchean planalto suite granites and associated charnockitic rocks of the canaa area of the carajas province, eastern amazonian craton.
Geochemistry of stype granitic rocks from the reversely. It has been recognized that atype granites can be formed in a variety of extensional regimes, such as continental backarc extension. Atype granitoids are ferroan alkalicalcic, although some are ferroan alkalic. The major difference lies in the fact that the stypes are invariably. Granite type tectonic environ chemical signature typical accessory minerals stype orogenic metaluminous to strongly peraluminous, high 18o16o, 87sr86sr muscovite, garnet, cordierite, tourmaline itype. Although weathering processes occur globally, no economic hree resources of. The field of geochemistry involves study of the chemical composition of the earth and other planets, the composition of rocks and soils, the cycles that involve the earths chemical components, and the interaction of those cycles with land and water. Petrology and geochemistry of lunar granite 12032,36619 and implications for lunar granite petrogenesis stephen m.
Geochronology, geochemistry, and petrology of the precambrian. The castelo branco pluton is a composite and zoned intrusionofperaluminouss type affinity. Garnet compositions were recast to endmembers using the minpet software of. Abstractthe study of the geochemistry, s type classification and petrography of idanre granite was undertaken. Zircon upb dating showed that the inner phase and outer phase of the safg were formed at 298. Redondo granite in literature, several authors have contributed to the geology, structure, petrography, geochemistry and geochronology knowledge on the granitic and volcanic rocks constituted therein e.
The american association of petroleum geologists is an international organization with over 38,000 members in 100plus countries. Feb 12, 2014 granites classification, petrogenesis and tectonic discriminations presented by. Other granites, known as i type, result from the melting of infracrustallyformed rocks. Geology, petrography and geochemistry of the atype granites from. Granites occur exclusively in the upper thrust sheet and the lowermost part of the ebsg. In this paper we are concerned with i type granites.
Geochemical classification for granitic rocks journal of petrology. Pdf biotite and twomica granites are common in continental crust. In the conterminous united states, ages of a type granitoid rocks are restricted to the period between. Geochemistry, geochronology, and origin of the neoarchean. These are formed above volcanic hot spot activity and have peculiar geochemistry and mineralogy. Geochemical, field and petrological data suggest that nakora granites are the product of partial melting of rocks similar to banded gneiss from kolar schist belt of india. The a type granites form in an extensional tectonic setting. The granite shows an intrusive contact with the metamorphic country rocks.
They appears to be a special variety of itype granites. Itype granitoids are dominantly calcalkalic and calcic. W and licsta geochemical signatures in itype granites. Isoplot program ludwig, 1999 was used for the plots and regression. According to the original definition of chappell and white, 1974, chappell and white, 1992 for stype and itype granites, it has the firstorder importance to discriminate between metasedimentary and metaigneous sources when dealing with granite petrogenesis. For further information contact manager repository services. Petrogenesis of highly fractionated itype granites in the zayu area. The rbsr whole rock isochron age of the country rocks is 1. Discrimination between archean atype granitoids and sanukitoid suites using tectonic setting, geochemistry and fertility type zozulya, d.
Pdf distinction between stype and peraluminous itype granites. Itype granites are saturated in silica but undersaturated in aluminum. Geochemistry of i and atype granites of the qingyang. Other granites, known as itype, result from the melting of infracrustallyformed rocks. I and stype granites in the lachlan fold belt the second. An early cretaceous garnetbearing metaluminous atype granite. Abstractthe study of the geochemistry, stype classification and petrography of idanre granite was undertaken. In this paper we are concerned with itype granites. This list is intended to facilitate representation of geochemical data to support teaching and research in the geosciences. Heavy rare earth elements hree are dominantly mined from the weathering crusts of granites in south china. The atype geochemical signature, a sourcerelated characteristic, probably derives from a crustal protolith from which itype granitic melts had been previously extracted.
Geology, geophysics, and geochemistry science center. This software and related material data and documentation are made available by the u. Geochemical classification for granitic rocks journal of. Some of the distinctive chemical properties of the two types are shown in the following table. The nakora granites are characterized as atype granites whalen et al. Mineralogy and geochemistry of anorogenic granitic miarolitic pegmatites associated with the white mountain intrusive suite, new hampshire a thesis submitted to the graduate faculty of the university of new orleans in partial fulfillment of the requirements for the degree of master of science in earth and environmental sciences by. Geochemistry of highly fractionated i and stype granites. They display geochemical characteristics of atype granites and distinct variation trends with increasing. Mineralogy and geochemistry of anorogenic granitic miarolitic. This sysrematic survey of opaque mineral assemblages and mafic mineral chemistry, in the same specimens from which i and s type granite classification was developed, was under. The heemskirk batholith is composite, and consists of a volatile f, b, h 2 orich stype granite underlying an itype granite. However, a garnetbearing atype granite intrusion occurs at the erlangmiao and.
Atype granites or alkaline, peralkaline and metaluminousperalumi nous granitoids constitute a considerable volume of the. Since the introduction of the atype granite classification by loiselle and wones, rocks of this type have been studied extensively due to their important geodynamic significance, complicated petrogenesis and economic potential 2,3,4,5,6,7,8,9,10,11,12. Its evidence is intricate and subtle, which makes experts arguing on this type of granite for a long time. Origin of heavy rare earth mineralization in south china. Although weathering processes occur globally, no economic hree resources of this type. Software facilitates the comparison of two curves which have equivalent x axis parameters. The florida canyon evaporiterelated znpb sulfide deposit, in northern peru, is one of the largest mississippi valleytype mvt deposits in south america. The purposes of this association are to advance the science of geology. Geochemistry of highly fractionated i and s type granites from the tintungsten province of western tasmania orebearing granite systems.
Geochemistry software free for students submitted by michele. For instance, one may wish to compare two probability density curves derived from geochronological investigations or compare two isotope proxy curves for a given time period. Geochemistry and petrogenesis of neoproterozoic atype. Good discrimination can be obtained between atype granites and most orogenic granites m, i and stypes on plots employing gaal, various major element ratios and y, ce, nb and. Granites classification, petrogenesis and tectonic. Corfuc a polytechnic institute of castelo branco, 6000919 castelo branco, portugal b department of earth sciences, university of coimbra, 3000272 coimbra, portugal c department of geosciences, university of oslo, pb1047 blindern, n. Itype granites are a category of granites originating from igneous sources, first proposed by chappell and white 1974. These result in itype granitoids, derived from igneous protoliths and containing moderate amounts of al2o3 and high amounts of na2o, and stype granitoids, derived from sedimentary protoliths and containing high amounts of al2o3 and relatively low amounts of na2o. Zoning is more visible in i type granites, while in s type granites it can be due to differences in the composition of the metapelitic source that partially melted e. The linear trends in major element plots for the biotite granite units may be. The granite class was proposed by loiselle and wones in 1979. The age of a type magmatism in north america ranges from about 1. Petrological and geochemical constraints in the origin and.
Examples from neoproterozoic and phanerozoic orogens. The age of atype magmatism in north america ranges from about 1. Geochemistry american association of petroleum geologists. Optimize every element of your prospecting operations worldwide using our advanced oil and gas exploration softwarea suite of comprehensive digital solutions for each stage of a petroleum systems approach to discovering hydrocarbons. They are of two distinct age groups, an older group with ages around 930 ma, and a younger group of caledonian granites, about 435 ma shrimp zircon upb ages, kalsbeek et al. Geochemistry of highly fractionated i and stype granites from the tintungsten province of western tasmania orebearing granite systems. Atype granites, geochemistry, petrography, graciosa province. It is built using the windows version of r, which provides a flexible and comprehensive language and environment for data analysis and graphics. Upb geochronology, geochemistry and srndhf isotopes. The complex consists of several terranes distributed ewstrikingly in the lishan, xiaoshan, xiongershan, lushan, wuyang and huoqiu. Chemical variation, modal composition and classification of granitoids. Geochemical characteristics of sand itype granites.
We will use the term granite very broadly to include plutonic rocks containing more than 53% sio2, that is the family of rocks ranging through from. Granites classification, petrogenesis and tectonic discriminations presented by. Welcome to the geology, geophysics, and geochemistry science center gggsc located in lakewood, colorado on the denver federal center. It is important to estimate the spatial variations in both statistics because such information is indicative of geological and other earth. Discrimination between archean a type granitoids and sanukitoid suites using tectonic setting, geochemistry and fertility type zozulya, d. In order to identify their source nature, this paper presents a combined study of. The a type geochemical signature, a sourcerelated characteristic, probably derives from a crustal protolith from which itype granitic melts had been previously extracted. Eighteen granite samples were analysed for their major, traceand rare earth elements using x ray fluorescence xrf and inductively coupled plasmamass spectrometry icp ms respectively. Petrology and geochemistry of lunar granite 12032,36619.
The field of geochemistry involves study of the chemical composition of the earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the earths chemical components in time and space, and their interaction with the hydrosphere and the atmosphere. The field of geochemistry involves study of the chemical composition of the earth and other planets, chemical processes and reactions that govern the composition of rocks and soils, and the cycles of matter and energy that transport the earths chemical components in time and space, and their interaction with the hydrosphere and the atmosphere the most important fields of geochemistry are. However, when working with large or complex data sets, speciallydesigned geochemical database and plotting software offer several significant advantages. Experimental data indicate that the geochemistry of a type granites is dependent on source composition and f o2 condition dallagnol et. Petrography, garnet chemistry and whole rock geochemistry suggest that the. Petrogenesis and mineralizing processes continental growth and recycling by accretion of deformed turbidite fans and remnant ocean basins.
Geological society of america, abstracts with programs. Granite the term granite is derived from latin word granum meaning grain because of its granular nature. Granitoid rocks derived from sedimentary source rocks, usually peraluminous, with muscovite and alrich minerals like garnet, cordierite and andalusite. Amphibole and pyroxene are more common in itype granitoids, while stype granitoids may have garnet, cordierite, and sillimanite. Bibliography includes bibliographical references and index. Using regional stream sediment geochemistry, this study aims to delineate the rather unusual occurrence of sn, w and licsta in itype cvmgk granites and relates the enrichment of these elements to crustal anatexis of metasedimentary and metaigneous source rocks during later stages of the variscan orogeny. Geological survey usgs to be used in the public interest and the advancement of science. This sysrematic survey of opaque mineral assemblages and mafic mineral chemistry, in the same specimens from which i and stype granite classification was developed, was under. This list is intended to facilitate representation of geochemical data to support teaching and research in the. They are recognized by a specific set of mineralogical, geochemical, textural, and isotopic characteristics that indicate, for example, magma hybridization in the deep crust. Most geochemical data can also be readily evaluated using spreadsheet applications e. The three hummock island, interview river, sandy cape, and conical rocks plutons probably have an stype source and are grouped together as the sandy cape suite. They are characterised by low water and a lack of tectonic fabric. The anhydrous nature of atype granite, low abundance of rb and fairly high sr contents contradict the formation of atype melts by anhydrous mineral fractionation from i type magma1.