Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/92742
Type: Thesis
Title: Controls on iron isotope variation in granites and associated hydrothermal ore systems: The Hillside example
Author: Kirk, J. T.
Issue Date: 2012
School/Discipline: School of Earth and Environmental Sciences
Abstract: This study presents accurate and precise iron isotopic data for the Hillside ore body relating it back to modelled δ57Fe values of the coeval magmatic suite comprising of the Curramulka Gabbronorite, Arthurton Granite, Tickera Granite and altered granites associated with the Hillside ore deposit. Defining the possible link between the hydrothermal system that deposited the Hillside ore body and the magmatic evolution of the Hiltaba suite granites that host the ore in relation to its δ57Fe. Radiogenic isotope data suggests some open system behaviour with minor crustal contamination occurring within the magmatic suite. The iron enrichment trend is initially defined by the crystallisation of pyroxenes and olivine causing the δ57Fe of the melt to increase. This is followed by the crystallisation of magnetite which causes the δ57Fe of the melt to decrease. Finally at the felsic end of the suite (>70% wt. % SiO2) the δ57Fe of the melt increases again. It is during this latter stage that hydrothermal fluid is released and using the data from the melts model it is believed that it had a δ57Fe ≈ +0.18. Two fluids were involved in the precipitation of the ore body. The primary fluid precipitated the magnetite and pyrite. Whilst the secondary fluid altered the pyrite to chalcopyrite and magnetite to hematite. Ore mineral separates for pyrite and chalcopyrite gave δ57Fe average values of 0.48 and -0.32 respectively. With pyrite being isotopically heavier than chalcopyrite the predicted outcome. The postulated δ57Fe value of the hydrothermal fluid (δ57Fe ≈ +0.18) was used to predict what range of δ57Fe that the ore minerals should fall within for the temperature range of 700-450oC. Only the pyrite mineralisation can be used to describe the δ57Fe relationship between the suite and ore body as it precipitated from the primary fluid. The collected pyrite average value fell within the predicted range with a crystallisation temperature of ≈ 625oC
Dissertation Note: Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2012
Where: Gawler Craton, Yorke Peninsula, South Australia
Keywords: Honours; Geology; Iron isotope; magmatic suite; open system
Description: This item is only available electronically.
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the author of this thesis and do not wish it to be made publicly available, or you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals
Appears in Collections:School of Physical Sciences

Files in This Item:
File Description SizeFormat 
01frontGeoHon.pdfTitle page, abstract & contents370.46 kBAdobe PDFView/Open
02wholeGeoHon.pdfWhole thesis (as available)3.14 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.