The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia
The Late Ordovician-early Silurian (∼455435 Ma) Northparkes system is a group of silica-saturated, alkalic porphyry deposits and prospects that developed within the Macquarie island arc. The system is host to a spectacular and diverse range of rocks and alteration-mineralization textures that facili...
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ftunivtasecite:oai:ecite.utas.edu.au:132551 2023-05-15T17:09:59+02:00 The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia Pacey, P Wilkinson, JJ Owens, J Priest, D Cooke, DR Millar, IL 2019 application/pdf https://doi.org/10.5382/econgeo.4644 http://ecite.utas.edu.au/132551 en eng Economic Geology Publ Co http://ecite.utas.edu.au/132551/2/132551 - The anatomy of an alkalic porphyry Cu-Au system - author version.pdf http://dx.doi.org/10.5382/econgeo.4644 http://purl.org/au-research/grants/arc/IH130200004 Pacey, P and Wilkinson, JJ and Owens, J and Priest, D and Cooke, DR and Millar, IL, The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia, Economic Geology, 114, (3) pp. 441-472. ISSN 0361-0128 (2019) [Refereed Article] http://ecite.utas.edu.au/132551 Earth Sciences Geology Resource geoscience Refereed Article PeerReviewed 2019 ftunivtasecite https://doi.org/10.5382/econgeo.4644 2022-07-25T22:16:45Z The Late Ordovician-early Silurian (∼455435 Ma) Northparkes system is a group of silica-saturated, alkalic porphyry deposits and prospects that developed within the Macquarie island arc. The system is host to a spectacular and diverse range of rocks and alteration-mineralization textures that facilitate a detailed understanding of its evolution, in particular the nature and controls of porphyry-related propylitic alteration. The first intrusive phase at Northparkes is a pre- to early-mineralization pluton that underlies all the deposits and varies in composition from a biotite quartz monzonite to alkali feldspar granite. Prior to total crystallization, this pluton was intruded by a more primitive quartz monzonite that marks the onset of a fertile fractionation series. Toward its upper levels, the quartz monzonite is porphyritic and locally rich in Cu sulfides. Subsequently, a complex series of synmineralization quartz monzonite porphyries was emplaced. The quartz monzonite porphyry intrusions have a distinct pipe-like morphology and are ubiquitously K-feldsparaltered with a crystal-crowded porphyritic texture. The textures of the quartz monzonite porphyries and common occurrence of porphyry-cemented contact breccias indicate they were forcibly emplaced and of relatively low viscosity. The quartz monzonite porphyries are therefore interpreted as crystal-bearing, silicate melt-aqueous fluid slurries that represent the conduits through which deep-seated magmatic-derived ore fluid was discharged into the shallow crust (12 km depth). Each deposit is centered on a multiphase cluster of quartz monzonite porphyry intrusions that drove discrete hydrothermal systems. Initial fluid evolution was similar in all the deposits, with three major alteration facies developed as largely concentric zones around the quartz monzonite porphyry complexes. The innermost zone is host to Cu sulfide ore and dominated by K-feldspar alteration. This transitions outward through a shell of magnetite biotite alteration, with pyrite and minor ... Article in Journal/Newspaper Macquarie Island eCite UTAS (University of Tasmania) Economic Geology 114 3 441 472 |
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English |
topic |
Earth Sciences Geology Resource geoscience |
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Earth Sciences Geology Resource geoscience Pacey, P Wilkinson, JJ Owens, J Priest, D Cooke, DR Millar, IL The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia |
topic_facet |
Earth Sciences Geology Resource geoscience |
description |
The Late Ordovician-early Silurian (∼455435 Ma) Northparkes system is a group of silica-saturated, alkalic porphyry deposits and prospects that developed within the Macquarie island arc. The system is host to a spectacular and diverse range of rocks and alteration-mineralization textures that facilitate a detailed understanding of its evolution, in particular the nature and controls of porphyry-related propylitic alteration. The first intrusive phase at Northparkes is a pre- to early-mineralization pluton that underlies all the deposits and varies in composition from a biotite quartz monzonite to alkali feldspar granite. Prior to total crystallization, this pluton was intruded by a more primitive quartz monzonite that marks the onset of a fertile fractionation series. Toward its upper levels, the quartz monzonite is porphyritic and locally rich in Cu sulfides. Subsequently, a complex series of synmineralization quartz monzonite porphyries was emplaced. The quartz monzonite porphyry intrusions have a distinct pipe-like morphology and are ubiquitously K-feldsparaltered with a crystal-crowded porphyritic texture. The textures of the quartz monzonite porphyries and common occurrence of porphyry-cemented contact breccias indicate they were forcibly emplaced and of relatively low viscosity. The quartz monzonite porphyries are therefore interpreted as crystal-bearing, silicate melt-aqueous fluid slurries that represent the conduits through which deep-seated magmatic-derived ore fluid was discharged into the shallow crust (12 km depth). Each deposit is centered on a multiphase cluster of quartz monzonite porphyry intrusions that drove discrete hydrothermal systems. Initial fluid evolution was similar in all the deposits, with three major alteration facies developed as largely concentric zones around the quartz monzonite porphyry complexes. The innermost zone is host to Cu sulfide ore and dominated by K-feldspar alteration. This transitions outward through a shell of magnetite biotite alteration, with pyrite and minor ... |
format |
Article in Journal/Newspaper |
author |
Pacey, P Wilkinson, JJ Owens, J Priest, D Cooke, DR Millar, IL |
author_facet |
Pacey, P Wilkinson, JJ Owens, J Priest, D Cooke, DR Millar, IL |
author_sort |
Pacey, P |
title |
The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia |
title_short |
The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia |
title_full |
The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia |
title_fullStr |
The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia |
title_full_unstemmed |
The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia |
title_sort |
anatomy of an alkalic porphyry cu-au system: geology and alteration at northparkes mines, new south wales, australia |
publisher |
Economic Geology Publ Co |
publishDate |
2019 |
url |
https://doi.org/10.5382/econgeo.4644 http://ecite.utas.edu.au/132551 |
genre |
Macquarie Island |
genre_facet |
Macquarie Island |
op_relation |
http://ecite.utas.edu.au/132551/2/132551 - The anatomy of an alkalic porphyry Cu-Au system - author version.pdf http://dx.doi.org/10.5382/econgeo.4644 http://purl.org/au-research/grants/arc/IH130200004 Pacey, P and Wilkinson, JJ and Owens, J and Priest, D and Cooke, DR and Millar, IL, The anatomy of an alkalic porphyry Cu-Au system: geology and alteration at Northparkes Mines, New South Wales, Australia, Economic Geology, 114, (3) pp. 441-472. ISSN 0361-0128 (2019) [Refereed Article] http://ecite.utas.edu.au/132551 |
op_doi |
https://doi.org/10.5382/econgeo.4644 |
container_title |
Economic Geology |
container_volume |
114 |
container_issue |
3 |
container_start_page |
441 |
op_container_end_page |
472 |
_version_ |
1766066367682838528 |