Variation in the composition of apatite in the Munni Munni Complex and associated intrusions of the West Pilbara Block, Western Australia

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doi: 10.1016/0016-7037(93)90496-J
Authors:Boudreau, Alan E.; Love, Coleen; Hoatson, Dean M.
Author Affiliations:Primary:
Duke University, Department of Geology, Durham, NC, United States
Australian Geological Survey Organisation, Australia
Volume Title:Geochimica et Cosmochimica Acta
Source:Geochimica et Cosmochimica Acta, 57(18), p.4467-4477. Publisher: Pergamon, Oxford, International. ISSN: 0016-7037
Publication Date:1993
Note:In English. 32 refs.; illus. incl. 2 tables, geol. sketch maps
Summary:EPMA are presented of apatites separated from the Munni Munni complex and two associated intrusions, the Radio Hill and Mount Sholl complexes. The mole fraction of fluorapatite increases from approx 60-70% in cumulates of the ultramafic zone in the Munni Munni complex to > 90% near the top of the gabbroic zone. Chlorapatite decreases from 30 mol% in the ultramafic zone to approx 10% in the uppermost gabbroic zone. The REE contents of apatite parallel stratigraphic changes in whole-rock Zr and Rb contents and are consistent with equilibration with the bulk assemblage. The stratigraphic variation is explained by the separation of a volatile fluid phase during crystallization with the loss of Cl and OH relative to F. The results of halogen fractionation during solidification of the intercumulus liquid are attributed to compositional variations on the microscopic scale. [R.K.H.]
Subjects:Apatite; Archean; Chemical composition; Chlorine; Fluorapatite; Fluorine; Halogens; Igneous rocks; Intrusions; Petrology; Phosphates; Precambrian; Australasia; Australia; Pilbara Craton; Western Australia; Fractionation; Mount Sholl; Munni Munni Complex; Radio Hill
Abstract Numbers:94M/3548
Record ID:1993046088
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
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