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19-791: QAPF diagrams are created by the International Union of Geological Sciences (IUGS): Subcommission on the Systematics of Igneous Rocks as fostered by Albert Streckeisen (whence their alternative name: Streckeisen diagrams). Geologists worldwide use the diagrams in classifying igneous, especially plutonic rocks. QAPF diagrams are mostly used to classify plutonic rocks ( phaneritic rocks), and can be used to classify volcanic rocks ( aphanitic rocks ) if modal mineralogical compositions have been determined. But QAPF diagrams are not used to classify pyroclastic rocks or volcanic rocks if modal mineralogical compositions are not determined . There

38-452: A horizontal line representing 37.5% quartz and then plotting a point on it 60% of the way across from the A side to the P side. For this example the rock can be classified as a Monzogranite. And, a plutonic rock that contains no feldspathoids (F group), no alkali feldspar (A group), but contains plagioclase-feldspar (P group), many pyroxenes (not labeled in a QAPF diagram), and few quartz grains (Q group)—is probably gabbro; (see right edge of

57-407: A rock identified as having, say, 20% mica, 30% quartz (Q), 30% alkali feldspar (A), and 20% plagioclase (P), the mica is disregarded, and the normalized ratios (proportions) of the Q, A, and P groups are calculated as 37.5%, 37.5% and 25% = 100%. Of these, the (again) normalised relative proportions of A and P are 37.5/62.5 = 60% and 25/62.5 = 40%. The rock can now be plotted on the diagram by finding

76-616: Is a joint partner with UNESCO for the International Geoscience Programme (IGCP) and also participates in the Global Geoparks Network (GGN). The Geological Society of London oversees the production and distribution of IUGS Publications. The Geological Society of India produces and distributes the Union's quarterly journal, entitled Episodes , as well as providing editorial support. Interested parties can download

95-530: Is an international non-governmental organization that unites scientific bodies at various levels across the social and natural sciences. The ISC was formed with its inaugural general assembly on 4 July 2018 by the merger of the former International Council for Science (ICSU) and the International Social Science Council (ISSC), making it one of the largest organisations of this type. Daya Reddy , mathematician , served (2018–2021) as

114-475: Is drawn as two mutually exclusive triangle plots , i.e., QAP and FAP. These are joined along one side such that, between them, each of the two triangle plots exclude either the Q group or F group minerals. (Other mineral groups may occur in samples, but they are disregarded in this classification method.) To use this classification method, the concentrations (the modes) of the four mineral groups must be determined or estimated, and then normalized to 100%. Thus, for

133-665: Is headquartered in Paris with a regional office in Colombia . The Officers of the Governing Board are currently Peter Gluckman (President), Motoko Kotani (President-elect), Anne Husebekk (Vice-President for Freedom and Responsibility in Science), Salim Abdool Karim (Vice-President for Outreach and Engagement), and Sawako Shirahase (Vice-President for Finance of the Council). The ISC's next assembly

152-468: Is not used for all plutonic rocks; the ultramafic plutonic rocks are the most important of groups that have separate classification diagrams; (see Streckeisen diagram). International Union of Geological Sciences The International Union of Geological Sciences ( IUGS ) is an international non-governmental organization devoted to international cooperation in the field of geology . As of 2023, it represents more than 1 million geoscientists around

171-659: The Stein Rokkan Prize for Comparative Social Science Research . The Council's present activities are guided by the Action Plan 2022-2024: Science and Society in Transition. At the heart of the Action Plan is a selection of projects and programmes that are relevant to all scientific fields and all parts of the world. The Council is governed by its Governing Board and is advised by a number of advisory bodies in thematic areas such as space, polar, climatic, and data research. It

190-455: The TAS classification (Total-Alkali-Silica) is used. TAS is also used if volcanic rock contains volcanic glass (such as obsidian ). QAPF diagrams are not used if mafic minerals make up more than 90% of the rock composition (for example: peridotites and pyroxenites ). Instead, an alternate triangle plot diagram is used; (see Streckeisen diagram, lower right.) An exact name can be given only if

209-449: The Council's CEO . In 2023, Salvatore Aricò was elected Chief Executive Officer . The Council convenes and mobilizes the international scientific community on issues of major scientific and public importance. Activities focus on three areas of work: The Council is involved in co-sponsorship of a number of international research programmes, networks and committees. The Council awards

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228-501: The ISC's inaugural President. Sir Peter Gluckman , pediatrician , biomedical scientist, and science-policy expert, was elected President in October 2021. Other ISC's inaugural Officers elected for the term of 2018–2021 were Elisa Reis (Vice President), Jinghai Li (Vice President), Renée van Kessel (Treasurer), and Alik Ismail-Zadeh (Secretary). Until February 2022, Heide Hackmann served as

247-618: The IUGS. A broad range of scientific topics are covered by its commission, task groups, joint programmes and affiliated organizations. IUGS promotes and encourages the study of geological problems, especially those of worldwide significance, and supports and facilitates international and inter-disciplinary co-operation in the earth sciences. The Union's Secretariat is currently located at the Chinese Academy of Geological Sciences in Beijing, China. IUGS

266-486: The Streckeisen diagram, at side P). This diagram makes no distinction between rock types at the same QAPF plot position and classification, but of different bulk chemical compositions with respect to other minerals such as olivine, pyroxenes, amphiboles or micas. For example, because non-Q, -A, -P and -F minerals are disregarded the system does not distinguish between gabbro , diorite , and anorthosite . The QAPF diagram

285-726: The congress was postponed twice and developed online in 2021. The 37th was held in August 2024 in Busan . Canada won the bid to host the 38th IGC in Calgary in 2028. To celebrate the sixtieth anniversary of its establishment, in 2022, IUGS published a list of 100 sites around the world that it holds to be significant in the development of the earth sciences. In 2024, IUGS published a second list of another 100 geological heritage sites. The IUGS Scientific Awards of Excellence: International Science Council The International Science Council ( ISC )

304-497: The latest issues of Episodes free of charge. Other activities include: Resourcing Future Generations (RFG), Young Reporters, Deep-Time Digital Earth (DDE). IUGS runs nine international commissions, covering the following topics: The International Union of Geological Sciences is the main scientific sponsor of the International Geological Congress (IGC), which takes place every four years. The first congress

323-549: The mineralogical composition is established, which cannot be determined in the field. The QAPF diagram presents for use the proportions (ratios) of four plutonic mineral(s) or mineral groups, which are: quartz (Q), the Alkali feldspars (A), the plagioclase feldspars (P), and the feldspathoids (F). Because F and Q groups cannot simultaneously form in plutonic rocks—due to the difference in their respective silica contents—the QAPF diagram

342-691: The world. The IUGS was founded in 1961 to ensure continued collaboration between the International Geological Congresses, which have taken place every four years since 1875. It is a Scientific Union member of the International Science Council (ISC), formerly the International Council for Science (ICSU), which it recognizes as the co-ordinating body for the international organization of science. Currently geologists from 121 countries (and regions) are represented in

361-554: Was in France in 1878 where a few geoscientists gathered to share new finds and .tTm was to create a framework and a platform for geoscientists to meet at regular intervals. The event has been growing bigger with each congress. Brisbane hosted the 34th congress in August 2012 and Cape Town the 35th in 2016. Delhi was to host the 36th in March 2020 as a collaborative effort by Bangladesh, India, Nepal, Pakistan and Sri Lanka. Because of Covid,

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