This page intentionally left blank IGNEOUS ROCKS: A CLASSIFICATION AND GLOSSARY OF TERMS Decades of field and microscope studies and more recent quantitative geo- chemicalanalyseshaveresultedinavast,andsometimesoverwhelming,array of nomenclature and terminology associated with igneous rocks. Under the auspices of the International Union of Geological Sciences (IUGS), a group ofpetrologistsfromaroundtheworldhaslabouredformorethan30yearsto collate these terms, gain international agreement on their usage, and reassess themethodsbywhichwecategorizeandnameigneousrocks. This book presents the results of their work and gives a complete classifi- cation of igneous rocks based on all the recommendations of the IUGS Sub- commissionontheSystematicsofIgneousRocks.Revisedfromthe1stedition (1989), it shows how igneous rocks can be distinguished in the sequence of pyroclasticrocks,carbonatites,melilite-bearingrocks,kalsilite-bearingrocks, kimberlites,lamproites,leucite-bearingrocks,lamprophyresandcharnockites. It also demonstrates how the more common plutonic and volcanic rocks that remaincanthenbecategorizedusingthefamiliarandwidelyacceptedmodal QAPFandchemicalTASclassificationsystems.Theglossaryofigneousterms hasbeenfullyupdatedsincethe1steditionandnowincludes1637entries,of which316arerecommendedbytheSubcommission,312areregardedaslocal terms,and413arenowconsideredobsolete. Incorporating a comprehensive list of source references for all the terms included in the glossary, this book will be an indispensable reference guide forallgeologistsstudyingigneousrocks,eitherinthefieldorthelaboratory. Itpresentsastandardizedandwidelyacceptednamingschemethatwillallow geologiststointerpretterminologyfoundintheprimaryliteratureandprovide formalnamesforrocksamplesbasedonpetrographicanalyses. Work on this book started as long ago as 1958 when Albert Streckeisen was asked to collaborate in revising Paul Niggli’s well-known book Tabellen zurPetrographieundzumGesteinbestimmen(TablesforPetrographyandRock Determination).ItwasatthispointthatStreckeisennotedsignificantproblems withall12oftheclassificationsystemsusedtoidentifyandnameigneousrocks atthattime.Ratherthanproposea16thsystem,hechoseinsteadtowriteareview articleoutliningtheproblemsinherentinclassifyingigneousrocksandinvited petrologistsfromaroundtheworldtosendtheircomments.In1970thislead totheformationoftheSubcommissionoftheSystematicsofIgneousRocks, undertheIUGSCommissiononPetrology,whopublishedtheirconclusionsin the 1st edition of this book in 1989. The work of this international body has continuedtothisday,leadbyBrunoZanettinandlaterbyMikeLeBas.This fully revised 2nd edition has been compiled and edited by Roger Le Maitre, withsignificanthelpfromapanelofco-contributors. IGNEOUS ROCKS A Classification and Glossary of Terms Recommendationsofthe InternationalUnionofGeologicalSciences SubcommissionontheSystematicsofIgneousRocks R.W. LE MAITRE (EDITOR), A. STRECKEISEN, B. ZANETTIN, M.J. LE BAS, B. BONIN, P. BATEMAN, G. BELLIENI, A. DUDEK, S. EFREMOVA, J. KELLER, J. LAMEYRE, P.A. SABINE, R. SCHMID, H. SØRENSEN, A.R. WOOLLEY    Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge  , United Kingdom Published in the United States by Cambridge University Press, New York www.cambridge.org Information on this title: www.cambrid ge.org/9780521662154 © R.W. Le Maitre & International Union of Geological Sciences 2002 This book is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published in print format 2002 ISBN-13 978-0-511-06651-1 eBook (NetLibrary) ISBN-10 0-511-06651-1 eBook (NetLibrary) ISBN-13 978-0-521-66215-4 hardback ISBN-10 0-521-66215-X hardback Cambridge University Press has no responsibility for the persistence or accuracy of s for external or third-party internet websites referred to in this book, and does not guarantee that any content on such websites is, or will remain, accurate or appropriate. v Contents Figures......................................................................................................................................vi Tables.......................................................................................................................................vii Albert Streckeisen ..................................................................................................................viii Foreword to 1st edition..............................................................................................................x Chairman’s Preface.................................................................................................................xiii Editor’s Preface .......................................................................................................................xv 1 Introduction ...........................................................................................................................1 1.1 Changes to the 1st edition.............................................................................................1 2 Classification and nomenclature............................................................................................3 2.1 Principles......................................................................................................................3 2.1.1 Parameters used....................................................................................................4 2.1.2 Nomenclature.......................................................................................................4 2.1.3 Using the classification ........................................................................................6 2.2 Pyroclastic rocks and tephra.........................................................................................7 2.2.1 Pyroclasts .............................................................................................................7 2.2.2 Pyroclastic deposits..............................................................................................7 2.2.3 Mixed pyroclastic–epiclastic deposits..................................................................8 2.3 Carbonatites................................................................................................................10 2.4 Melilite-bearing rocks.................................................................................................11 2.4.1 Melilitolites........................................................................................................11 2.4.2 Melilitites ...........................................................................................................11 2.5 Kalsilite-bearing rocks................................................................................................12 2.6 Kimberlites..................................................................................................................13 2.6.1 Group I kimberlites............................................................................................13 2.6.2 Group II kimberlites...........................................................................................14 2.7 Lamproites..................................................................................................................16 2.7.1 Mineralogical criteria.........................................................................................16 2.7.2 Chemical criteria................................................................................................16 2.7.3 Nomenclature.....................................................................................................16 2.8 Leucite-bearing rocks .................................................................................................18 2.9 Lamprophyres.............................................................................................................19 2.10 Charnockitic rocks....................................................................................................20 2.11 Plutonic rocks............................................................................................................21 2.11.1 Plutonic QAPF classification (M < 90%) ........................................................21 2.11.2 Ultramafic rocks (M > 90%)............................................................................28 2.11.3 Provisional “field” classification......................................................................29 2.12 Volcanic rocks...........................................................................................................30 2.12.1 Volcanic QAPF classification (M < 90%)........................................................30 2.12.2 The TAS classification .....................................................................................33 2.12.3 Provisional “field” classification......................................................................39 2.13 References.................................................................................................................40 vi 3 Glossary of terms.................................................................................................................43 3.1 Details of entries.........................................................................................................43 3.1.1 Choice of terms..................................................................................................43 3.1.2 Petrological description......................................................................................43 3.1.3 Amphibole and pyroxene names........................................................................44 3.1.4 Source reference.................................................................................................44 3.1.5 Origin of name ...................................................................................................44 3.1.6 Location in standard texts ..................................................................................45 3.2 Historical perspective .................................................................................................46 3.3 Glossary......................................................................................................................49 4 Bibliography of terms........................................................................................................159 4.1 Bibliographic analysis...............................................................................................159 4.2 References.................................................................................................................162 Appendix A Lists of participants..........................................................................................209 A.1 Participants listed by country...................................................................................209 A.2 Participants listed by name (with country)..............................................................216 Appendix B Recommended IUGS names............................................................................221 Appendix C IUGSTAS software package............................................................................225 C.1 Introduction..............................................................................................................225 C.1.1 Data input ........................................................................................................225 C.1.2 Data output......................................................................................................225 C.1.3 Error checking.................................................................................................227 C.1.4 Supplied tasks..................................................................................................227 C.2 Getting started with C++..........................................................................................228 C.3 Useful routines.........................................................................................................230 C.3.1 Input routines...................................................................................................230 C.3.2 Output routines................................................................................................231 C.3.3 Calculation routines.........................................................................................233 C.4 The CIPW norm calculation.....................................................................................234 C.4.1 Problems..........................................................................................................234 C.4.2 IUGSTAS CIPW norm....................................................................................235 C.5 Downloading IUGSTAS ..........................................................................................236 C.6 References................................................................................................................236 Figures 2.1 Classification of polymodal pyroclastic rocks ...................................................................8 2.2 Chemical classification of carbonatites with SiO < 20%................................................10 2 2.3 Modal classification of volcanic rocks containing melilite..............................................11 2.4 QAPF modal classification of plutonic rocks...................................................................22 2.5 QAPF field numbers.........................................................................................................23 vii 2.6 Modal classification of gabbroic rocks.............................................................................25 2.7 Use of the terms mela- and leuco- with QAPF plutonic rocks with Q > 5%...................26 2.8 Use of the terms mela- and leuco- with QAPF plutonic rocks with Q < 5% or F > 0%..27 2.9 Modal classification of ultramafic rocks..........................................................................28 2.10 Preliminary QAPF classification of plutonic rocks for field use ...................................29 2.11 QAPF modal classification of volcanic rocks ................................................................31 2.12 Subdivision of volcanic QAPF field 15..........................................................................32 2.13 Chemical classification and separation of “high-Mg” volcanic rocks ...........................34 2.14 Chemical classification of volcanic rocks using TAS (total alkali–silica diagram).......35 2.15 Field symbols and coordinate points of TAS..................................................................36 2.16 Likelihood of correctly classifying alkali basalt and subalkali basalt using TAS..........37 2.17 Division of the basalt–rhyolite series into high-K, medium-K and low-K types...........37 2.18 Classification of trachytes and rhyolites into comenditic and pantelleritic types..........38 2.19 Preliminary QAPF classification of volcanic rocks for field use...................................39 3.1 Frequency with which new rock terms and their references have appeared....................47 Tables 2.1 Prefixes for use with rocks containing glass......................................................................5 2.2 Colour index terms.............................................................................................................5 2.3 Classification and nomenclature of pyroclasts and well-sorted pyroclastic rocks.............9 2.4 Terms to be used for mixed pyroclastic–epiclastic rocks...................................................9 2.5 Mineral assemblages of kalsilite-bearing volcanic rocks.................................................12 2.6 Nomenclature of the kamafugitic rock series...................................................................12 2.7 Nomenclature of lamproites .............................................................................................17 2.8 Mineralogy of principal groups of leucite-bearing volcanic rocks ..................................18 2.9 Classification and nomenclature of lamprophyres based on their mineralogy.................19 2.10 Nomenclature of charnockitic rocks...............................................................................20 2.11 Classification of QAPF fields 9 and 10 volcanic rocks into basalt and andesite...........30 3.1 Countries and linguistic roots found 12 or more times in the origin of new rock terms..45 3.2 Frequency of new rock terms and their references by century.........................................46 3.3 “Best” and “worst” periods since 1800 for new rock terms and their references............46 3.4 Years with 20 or more new rock terms and 10 or more references..................................46 4.1 Numbers of new rock terms and their references by publication language ...................159 4.2 Authors who introduced 10 or more new rock terms.....................................................160 4.3 Authors with 5 or more publications containing new rock terms...................................160 4.4 Journals and publishers with 20 or more new rock terms..............................................161 4.5 Journals and publishers with 10 or more publications containing new rock terms........161 C.1 List of oxide names and normative values.....................................................................226 C.2 Example of C++ code in task “TASNamesTest”...........................................................228 C.3 Example of a simple half-page table output by routine “WriteTable()”........................231 C.4 Example of a vertical table output by routine “WriteAsVertTable()”............................232 viii Albert Streckeisen 8 November 1901 – 29 September 1998 Albert Streckeisen was born on 8 November his nationality. He then decided to become a 1901 in Basel, Switzerland, into an old Basel school teacher and taught Natural Sciences in family. His father Dr Adolf Streckeisen was a Swiss high schools until his retirement in Berne Professor in Medicine. Later he studied in 1939. This also enabled him to become an geology, mineralogy and petrology in Basel, honorary professorial associate at the Univer- Zürich and Berne un- sity of Berne (1942) and der famous teachers to take part in the scien- like the Professors tific and teaching life of Buxdorf, Reinhard and the Earth Sciences at Paul Niggli. Berne, where he was In 1927, under the nominated extraordi- supervision of Prof. nary professor. Reinhard, he presented Albert Streckeisen – his doctoral thesis deal- Albert to his many ing with the geology friends in the Commis- and petrology of the sion and the world over Flüela group in the – started his work on Grisons of Eastern the classification and Switzerland. systematics of igneous In the same year, at rocks at an age of over the age of 26, he took 60. This kept him scien- up the position of ordi- tifically busy for more Photographed in Venice 1979 nary Professor in Min- than 35 years. eralogy and Petrology at the Polytechnic of The IUGS asked him to create and lead the then Bucharest in Romania. He also became a Commission on the Systematics of Magmatic member of the Romanian Geological Service Rocks, that became the IUGS Subcommission and was very active in the mapping programme on the Systematics of Igneous Rocks when simi- in the Carpathians. In addition to his interests lar groups for Metamorphic and Sedimentary in alpine petrography and structural analysis Rocks were formed. This commission, of which he became interested the petrography of the Albert Streckeisen was founder and spiritus rec- interesting and unique nepheline syenite mas- tor, will certainly remain as the “Streckeisen sif of Ditro in Transylvania, on which he Commission” in the same way and spirit that the published eight papers. This is almost cer- QAPF classification will remain the “Streckeisen tainly where his interest in the petrographic double triangle”. classification of igneous rocks started. It is certainly due to his concilient, but In the 1930s Albert Streckeisen returned to determined, firm personality and authority that Switzerland, as to remain professor in agreement in his Subcommission on “general Bucharest he would have been forced to change recommendations” was achieved. As a