Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton

Paulsens is a mesothermal orogenic gold deposit located in the Wyloo Inlier on the southern margin of the Pilbara craton of Western Australia. Gold occurs in quartz-sulfide veins hosted within a folded and faulted gabbro dike, from which baddeleyite yields a U-Pb crystallization age of 2701 ± 11 Ma....

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Main Authors: Fielding, I., Johnson, S., Zi, J., Rasmussen, Birger, Muhling, J., Dunkley, D., Sheppard, S., Wingate, M., Rogers, J.
Format: Journal Article
Published: Society of Economic Geologists Inc 2017
Online Access:http://purl.org/au-research/grants/arc/LP130100922
http://hdl.handle.net/20.500.11937/54497
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author Fielding, I.
Johnson, S.
Zi, J.
Rasmussen, Birger
Muhling, J.
Dunkley, D.
Sheppard, S.
Wingate, M.
Rogers, J.
author_facet Fielding, I.
Johnson, S.
Zi, J.
Rasmussen, Birger
Muhling, J.
Dunkley, D.
Sheppard, S.
Wingate, M.
Rogers, J.
author_sort Fielding, I.
building Curtin Institutional Repository
collection Online Access
description Paulsens is a mesothermal orogenic gold deposit located in the Wyloo Inlier on the southern margin of the Pilbara craton of Western Australia. Gold occurs in quartz-sulfide veins hosted within a folded and faulted gabbro dike, from which baddeleyite yields a U-Pb crystallization age of 2701 ± 11 Ma. Monazite and xenotime in the veins and from hydrothermally altered country rocks yield three distinct U-Pb dates of ca. 2400, 1730, and 1680 Ma. Textural relationships between euhedral xenotime and pyrite with rounded native gold inclusions from within the quartz-sulfide veins show that the primary gold mineralization was synchronous with xenotime crystallization at 2403 ± 5 Ma, and coeval with pervasive alteration of the host rocks, which yield monazite ages of 2398 ± 37 and 2403 ± 38 Ma. Regional-scale hydrothermal events at ca. 1730 and 1680 Ma are linked to the growth of monazite within phyllitic rocks at 1730 ± 28 and 1721 ± 32 Ma, carbonate veining at 1655 ± 37 Ma, and gold remobilization or introduction of new gold at 1680 ± 9 Ma. The ca. 2400 Ma age for mineralization and hydrothermal alteration does not correspond with any known deformation event in the region, indicating a significantly different and more complicated low-temperature tectonothermal evolution for the southern Pilbara region than previously recognized. The in situ secondary ion mass spectrometry dating of monazite and xenotime employed here will lead to better targeting of orogenic gold deposits in the northern Capricorn Orogen, and these techniques can be utilized for orogenic gold exploration worldwide.
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spelling curtin-20.500.11937-544972022-11-23T07:50:01Z Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton Fielding, I. Johnson, S. Zi, J. Rasmussen, Birger Muhling, J. Dunkley, D. Sheppard, S. Wingate, M. Rogers, J. Paulsens is a mesothermal orogenic gold deposit located in the Wyloo Inlier on the southern margin of the Pilbara craton of Western Australia. Gold occurs in quartz-sulfide veins hosted within a folded and faulted gabbro dike, from which baddeleyite yields a U-Pb crystallization age of 2701 ± 11 Ma. Monazite and xenotime in the veins and from hydrothermally altered country rocks yield three distinct U-Pb dates of ca. 2400, 1730, and 1680 Ma. Textural relationships between euhedral xenotime and pyrite with rounded native gold inclusions from within the quartz-sulfide veins show that the primary gold mineralization was synchronous with xenotime crystallization at 2403 ± 5 Ma, and coeval with pervasive alteration of the host rocks, which yield monazite ages of 2398 ± 37 and 2403 ± 38 Ma. Regional-scale hydrothermal events at ca. 1730 and 1680 Ma are linked to the growth of monazite within phyllitic rocks at 1730 ± 28 and 1721 ± 32 Ma, carbonate veining at 1655 ± 37 Ma, and gold remobilization or introduction of new gold at 1680 ± 9 Ma. The ca. 2400 Ma age for mineralization and hydrothermal alteration does not correspond with any known deformation event in the region, indicating a significantly different and more complicated low-temperature tectonothermal evolution for the southern Pilbara region than previously recognized. The in situ secondary ion mass spectrometry dating of monazite and xenotime employed here will lead to better targeting of orogenic gold deposits in the northern Capricorn Orogen, and these techniques can be utilized for orogenic gold exploration worldwide. 2017 Journal Article http://hdl.handle.net/20.500.11937/54497 10.5382/econgeo.2017.4507 http://purl.org/au-research/grants/arc/LP130100922 Society of Economic Geologists Inc fulltext
spellingShingle Fielding, I.
Johnson, S.
Zi, J.
Rasmussen, Birger
Muhling, J.
Dunkley, D.
Sheppard, S.
Wingate, M.
Rogers, J.
Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton
title Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton
title_full Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton
title_fullStr Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton
title_full_unstemmed Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton
title_short Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: An example from the Paulsens Mine, Southern Pilbara Craton
title_sort using in situ shrimp u-pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization: an example from the paulsens mine, southern pilbara craton
url http://purl.org/au-research/grants/arc/LP130100922
http://hdl.handle.net/20.500.11937/54497