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

I. O.H. Fielding, S. P. Johnson, J. W. Zi, B. Rasmussen, J. R. Muhling, D.J. J. Dunkley, S. Sheppard, M. T.D. Wingate, J. R. Rogers

    Research output: Contribution to journalArticle

    12 Citations (Scopus)

    Abstract

    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.

    Original languageEnglish
    Pages (from-to)1205-1230
    Number of pages26
    JournalEconomic Geology
    Volume112
    Issue number5
    DOIs
    Publication statusPublished - 1 Aug 2017

    Fingerprint

    Geochronology
    xenotime
    geochronology
    cratons
    monazite
    Gold
    craton
    gold
    mineralization
    Gold deposits
    Quartz
    veins
    Rocks
    Sulfides
    Crystallization
    rocks
    sulfides
    Levees
    crystallization
    quartz

    Cite this

    @article{eec85446bbaa40d2a5d11d4f7dd275bd,
    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",
    abstract = "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.",
    author = "Fielding, {I. O.H.} and Johnson, {S. P.} and Zi, {J. W.} and B. Rasmussen and Muhling, {J. R.} and Dunkley, {D.J. J.} and S. Sheppard and Wingate, {M. T.D.} and Rogers, {J. R.}",
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    doi = "10.5382/econgeo.2017.4507",
    language = "English",
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    pages = "1205--1230",
    journal = "Economic Geology",
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    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. O.H.; Johnson, S. P.; Zi, J. W.; Rasmussen, B.; Muhling, J. R.; Dunkley, D.J. J.; Sheppard, S.; Wingate, M. T.D.; Rogers, J. R.

    In: Economic Geology, Vol. 112, No. 5, 01.08.2017, p. 1205-1230.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Using in situ SHRIMP U-Pb monazite and xenotime geochronology to determine the age of orogenic gold mineralization

    T2 - An example from the Paulsens Mine, Southern Pilbara Craton

    AU - Fielding, I. O.H.

    AU - Johnson, S. P.

    AU - Zi, J. W.

    AU - Rasmussen, B.

    AU - Muhling, J. R.

    AU - Dunkley, D.J. J.

    AU - Sheppard, S.

    AU - Wingate, M. T.D.

    AU - Rogers, J. R.

    PY - 2017/8/1

    Y1 - 2017/8/1

    N2 - 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.

    AB - 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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    U2 - 10.5382/econgeo.2017.4507

    DO - 10.5382/econgeo.2017.4507

    M3 - Article

    VL - 112

    SP - 1205

    EP - 1230

    JO - Economic Geology

    JF - Economic Geology

    SN - 0361-0128

    IS - 5

    ER -