A Geochemical Classification for Granitic Rocks

2001/11/01 by B. RONALD FROST, Calvin G. Barnes, CALVIN G. BARNES +8 · 4,273 citations
Chemistry · Computer Science · Earth and Planetary Sciences · #Geochemistry #Geochemistry and Geologic Mapping #Geological and Geochemical Analysis #Geology #Mineralogy #Peralkaline rock #Radioactive element chemistry and processing

paper · pdf · doi:10.1093/petrology/42.11.2033

published in Journal of Petrology 42(11), 2033-2048 (Oxford University Press)

openalex publication_date 2001/11/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04

Abstract

This geochemical classification of granitic rocks is based upon three variables. These are FeO/(FeO + MgO) = Fe-number [or FeOtot/(FeOtot + MgO) = Fe*], the modified alkali–lime index (MALI) (Na2O + K2O – CaO) and the aluminum saturation index (ASI) [Al/(Ca – 1·67P + Na + K)]. The Fe-number (or Fe*) distinguishes ferroan granitoids, which manifest strong iron enrichment, from magnesian granitoids, which do not. The ferroan and magnesian granitoids can further be classified into alkalic, alkali–calcic, calc-alkalic, and calcic on the basis of the MALI and subdivided on the basis of the ASI into peraluminous, metaluminous or peralkaline. Because alkalic rocks are not likely to be peraluminous and calcic and calc-alkalic rocks are not likely to be peralkaline, this classification leads to 16 possible groups of granitic rocks. In this classification most Cordilleran granitoids are magnesian and calc-alkalic or calcic; both metaluminous and peraluminous types are present. A-type granitoids are ferroan alkali–calcic, although some are ferroan alkalic. Most are metaluminous although some are peraluminous. Caledonian post-orogenic granites are predominantly magnesian alkali–calcic. Those with <70 wt % SiO2 are dominantly metaluminous, whereas more silica-rich varieties are commonly peraluminous. Peraluminous leucogranites may be either magnesian or ferroan and have a MALI that ranges from calcic to alkalic.

Citations

• Tectonic discrimination of granitoids
• A-type granites: geochemical characteristics, discrimination and petrogenesis
• Petrogenetic interpretation of granitoid rock series using multicationic parameters
• Residence of REE, Y, Th and U in Granites and Crustal Protoliths; Implications for the Chemistry of Crustal Melts
• Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks
• Petrology, Geochemistry, and Genesis of High-Al Tonalite and Trondhjemites of the Cornucopia Stock, Blue Mountains, Northeastern Oregon
• Volcanic rock series in island arcs and active continental margins

Cited by

• Partial Melting of Mantle and Crustal Sources beneath South Karakorum, Pakistan: Implications for the Miocene Geodynamic Evolution of the India-Asia Convergence Zone
• Permian peralkaline, peraluminous and metaluminous A-type granites in the Panxi district, SW China: Their relationship to the Emeishan mantle plume
• Geochemical and geochronological studies of granitoid rocks from the Western Tianshan Orogen: Implications for continental growth in the southwestern Central Asian Orogenic Belt
• Trace element discrimination of arc, slab failure, and A-type granitic rocks
• Diverse Permian magmatism in the Tarim Block, NW China: Genetically linked to the Permian Tarim mantle plume?
• Crustal melting vs. fractionation of basaltic magmas: Part 1, granites and paradigms
• Metasedimentary melting in the formation of charnockite: Petrological and zircon U-Pb-Hf-O isotope evidence from the Darongshan S-type granitic complex in southern China
• Permian A-type granites in Tarim and western part of Central Asian Orogenic Belt (CAOB): Genetically related to a common Permian mantle plume?
• Multiple sources of the Early Mesozoic Gouli batholith, Eastern Kunlun Orogenic Belt, northern Tibetan Plateau: Linking continental crustal growth with oceanic subduction
• Geochronology, petrogenesis and tectonic implications of Triassic granitoids from Beishan, NW China
• Petrogenesis and tectonic implications of Late Devonian arc volcanic rocks in southern Beishan orogen, NW China: Geochemical and Nd–Sr–Hf isotopic constraints
• Geochronology, geochemical and Sr–Nd–Hf-Pb isotopic compositions of the granitoids in the Yemaquan orefield, East Kunlun orogenic belt, northern Qinghai-Tibet Plateau: Implications for magmatic fractional crystallization and sub-solidus hydrothermal alteration
• Contribution of Columbia and Gondwana Supercontinent assembly- and growth-related magmatism in the evolution of the Meghalaya Plateau and the Mikir Hills, Northeast India: Constraints from U-Pb SHRIMP zircon geochronology and geochemistry
• Geochemistry, geochronology, and Sr–Nd isotopes of the Late Neoproterozoic Wadi Kid volcano-sedimentary rocks, Southern Sinai, Egypt: Implications for tectonic setting and crustal evolution
• Derivation of the Early Carboniferous Wedgeport pluton by crystal fractionation of a mafic parental magma: a rare case of an A-type granite within the Meguma terrane (Nova Scotia, Canada)
• Post-collisional polycyclic plutonism from the Zagros hinterland: the Shaivar Dagh plutonic complex, Alborz belt, Iran
• The Paleo‐Tethys Suture Zone in the Afghan Hindu Kush‒Pamir: Geo‐Thermochronology, Geochemistry, Tectonics
• Mafic microgranular enclaves (MMEs) trace the origin of post-collisional magmas
• The Ouarzazate Supergroup and its plutonic keel: the relicts of an Ediacaran silicic large igneous province in North Africa
• Petrogenesis and Tectonic Implication of Jurassic Granites in Central Guangdong, SE China: Constraints from Zircon U-Pb-Hf-O and Whole-Rock Geochemical and Sr-Nd Isotopic Data
• Reconnaissance Basement Geology and Tectonics of South Zealandia
• U–Pb Geochronology and Petrogenesis of Dongargarh Granite, Bastar Craton, Central India: Insights Into Crustal Growth and Critical Metals Mineralization Across Archean‐Proterozoic Transition
• Archean granitoids: classification, petrology, geochemistry and origin
• A 4 Ga record of granitic heat production: Implications for geodynamic evolution and crustal composition of the early Earth
• A review of the granite concept through time
• Extent and significance of the Upper Ordovician felsic volcanism in the Pyrenees and Mouthoumet Massifs, SW Europe
• Volcano-Sedimentary Deposits: Overview of an Emerging Type of Lithium Resource
• Earth’s tectonic and plate boundary evolution over 1.8 billion years
• Geochemical and geochronological constraints on the Mesoproterozoic Red Granite Suite, Kunene AMCG Complex of Angola and Namibia
• Geochemical and geochronological signatures of granitoids from the Chaillu massif, Congo Craton: Insights into Mesoarchean crustal growth
• The Panjal Traps
• The boundaries of the West African craton, with special reference to the basement of the Moroccan metacratonic Anti-Atlas belt
• Coexisting A1 and A2 granites of Kudaru Complex: implications for genetic and tectonic diversity of A-type granite in the Younger Granite province, north-central Nigeria
• Neoproterozoic magmatic arc systems of the central Ribeira belt, SE-Brazil, in the context of the West-Gondwana pre-collisional history: A review
• Across-arc variation of the Famatinian magmatic arc (NW Argentina) exemplified by I-, S- and transitional I/S-type Early Ordovician granitoids of the Sierra de Velasco
• The 36–18 Ma Indian Peak–Caliente ignimbrite field and calderas, southeastern Great Basin, USA: Multicyclic super-eruptions
• A-type magmatism in the Western Lachlan Fold Belt? A study of granites and rhyolites from the Grampians region, Western Victoria
• Subduction of Proterozoic to Late Triassic continental basement in the Guatemala suture zone: A petrological and geochronological study of high-pressure metagranitoids from the Chuacús complex
• Early growth of the Indian lithosphere: Implications from the assembly of the Dharwar Craton and adjacent granulite blocks, southern India
• Crustal evolution of the Southern Granulite Terrane, south India: New geochronological and geochemical data for felsic orthogneisses and granites
• Geoquímica de las rocas plutónicas del batolito cambro-ordovícico del Cordón de Lila y de la Sierra de Almeida, Región de Antofagasta, Chile
• Geochemistry and UPb Zircon geochronology of Igurubi Granitoids, Nzega Greenstone Belt, Northern Tanzania: implications for crustal growth and timing of gold mineralization
• Geochemical dataset of high-pressure acid migmatites from the Cabo Ortegal Complex (NW Spain). [europepmc]
• Magmatic surge requires two-stage model for the Laramide orogeny. [europepmc]
• Geochemical characteristics, hazards impact assessment and radiogenic heat production of the alkaline rocks. [europepmc]
• Seasonal monitoring of forage C:N:ADF ratio in natural rangeland using remote sensing data. [europepmc]
• Petrogenesis and geodynamic implication of the newly recorded Cryogenian Suwaj adakitic magmatism at the eastern Arabian-Shield. [europepmc]
• Iso-stress architecture from mineral foliation patterns. [europepmc]
• Petrological diversity of continental arc magmatism evidenced by Triassic magmatic complexes in East Kunlun Orogen. [europepmc]
• Geochemical, radiological, and heat-production characteristics of the ElGara granitoids (Southwestern Desert). [europepmc]
• Remote sensing and geochemical constraints on polymetallic mineralization in Abu Rusheid and Sikait granites of Egypt. [europepmc]

Related

• Trace Element Discrimination Diagrams for the Tectonic Interpretation of Granitic Rocks
• A Guide to the Chemical Classification of the Common Volcanic Rocks
• A Chemical Classification of Volcanic Rocks Based on the Total Alkali-Silica Diagram
• A proposed new mineralogical classification system for granitic pegmatites
• A review of the granite concept through time