Carbonatites and Fenitization Associated with a Lamprophyric Dike-Swarm Intrusive into Schists of the New Zealand Geosyncline

Research Article| May 01, 1971 Carbonatites and Fenitization Associated with a Lamprophyric Dike-Swarm Intrusive into Schists of the New Zealand Geosyncline A. F COOPER A. F COOPER Department of Geology, University of Otago, Dunedin, New Zealand Search for other works by this author on: GSW Google Scholar Author and Article Information A. F COOPER Department of Geology, University of Otago, Dunedin, New Zealand Publisher: Geological Society of America Received: 03 Dec 1970 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1971, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1971) 82 (5): 1327–1340. https://doi.org/10.1130/0016-7606(1971)82[1327:CAFAWA]2.0.CO;2 Article history Received: 03 Dec 1970 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation A. F COOPER; Carbonatites and Fenitization Associated with a Lamprophyric Dike-Swarm Intrusive into Schists of the New Zealand Geosyncline. GSA Bulletin 1971;; 82 (5): 1327–1340. doi: https://doi.org/10.1130/0016-7606(1971)82[1327:CAFAWA]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract At Haast River, South Westland, a lamprophyric dike swarm with carbonatitic affinities intrudes schists of the New Zealand Geosyncline. The dike swarm comprises a series of consanguineous members ranging in composition from ultramafic hornblende-mica peridotite, through camptonitic lamprophyre and mafic sodalite-nepheline microsyenite, to sodalite-tinguaite, potassic trachyte, and carbonatite.One carbonatite dike, 1.25 m thick, consists predominantly of the Ba-Mg carbonate, norsethite (Ba0.96Mg0.79Fe0.14Sr0.02Mn0.03 Ca0.01(CO3)2.02) with subordinate magnesian siderite, aegirine, albite, pyrite, sphalerite, galena, and monazite. Other carbonatites contain siderite, norsethite-ankerite, and calcite-dolomite-barite assemblages.Metasomatic alteration of the country-rock schist, likened to fenitization, is most pronounced at the margins of alkalic and carbonatite dikes. It involves the introduction of Na2O, CO2, S, Nb, and Th into the country rock, with possible depletion in K2O. A progressive fenitization sequence from quartzofeldspathic schist to aegirine-crossite-albite schist is petrographically described and illustrated. An analysisis presented of crossite, typical of the strongly pleochroic blue amphibole produced during fenitization.The Haast River dike swarm intruded a geosynclinal terrain in immediately postorogenic times, postdating widespread metamorphism and intensive deformation of the Rangitata orogeny by at most about 10 m.y. Similarities between the Haast River occurrence and other carbonatite complexes from geosynclinal areas are briefly discussed. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.