Geochemical characterisation of xenotime formation environments using U-Th
Xenotime (YPO4) is a trace component in many metasedimentary and some igneous rocks, altered rocks and many hydrothermal ore assemblages, where it forms in response to a range of different processes from igneous crystallisation to low-temperature early diagenesis. Due to its wide range of formation...
| Main Authors: | , |
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| Format: | Journal Article |
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Elsevier Science BV
2017
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| Online Access: | http://hdl.handle.net/20.500.11937/56941 |
| _version_ | 1848759975546978304 |
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| author | McNaughton, Neal Rasmussen, B. |
| author_facet | McNaughton, Neal Rasmussen, B. |
| author_sort | McNaughton, Neal |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Xenotime (YPO4) is a trace component in many metasedimentary and some igneous rocks, altered rocks and many hydrothermal ore assemblages, where it forms in response to a range of different processes from igneous crystallisation to low-temperature early diagenesis. Due to its wide range of formation temperatures, its suitability and isotopic robustness for reliable U-Pb geochronology, dissolution/precipitation characteristics during overprint events, and widespread occurrence, it is one of the most valuable minerals for U-Pb geochronology leading to four-dimensional (4D) studies of many terranes. The formation environment of xenotime can be deduced from careful petrography and reliable U-Pb in-situ geochronology within a 4D framework. Further, xenotime is a physically robust mineral during sediment transport and may carry distinctive geochemical fingerprints, including age, to secondary environments.From published works, we review the U-Th-contents of well-characterised examples of xenotime formation to provide chemical fingerprints, which assist in identifying the xenotime formation environment. Although the U-Th characteristics of xenotime from all formation environments show considerable overlap, we make the following observations which may be distinctive of some ore formation environments: (i) hydrothermal xenotime formed from low salinity ore fluids (e.g. iron ore and orogenic gold deposits) trend to have the lowest U-contents ( < . 100. ppm U) and U/Th ( < . 4), in contrast to xenotime formed from higher salinity ore fluids (Sn-W and base metal deposits); (ii) xenotime associated with unconformity-related U-ores have the highest U-contents at U/Th. > . 10; (iii) diagenetic xenotime has the most variable and highest U/Th, whereas (iv) xenotime from Precambrian orogenic gold deposits has the least variable and lowest U/Th.Petrogenetic inferences from these observations for ore deposit research and exploration include: (i) support for the homogenising effect of the crustal scale of the fluid system in Precambrian orogenic gold deposits, and (ii) the potential for distinctive U-Th geochemical fingerprints for U ores and some Au ores. These characteristics may be reflected in detrital xenotime grains recovered from routine exploration sampling programs. |
| first_indexed | 2025-11-14T10:08:25Z |
| format | Journal Article |
| id | curtin-20.500.11937-56941 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T10:08:25Z |
| publishDate | 2017 |
| publisher | Elsevier Science BV |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-569412018-04-19T03:56:00Z Geochemical characterisation of xenotime formation environments using U-Th McNaughton, Neal Rasmussen, B. Xenotime (YPO4) is a trace component in many metasedimentary and some igneous rocks, altered rocks and many hydrothermal ore assemblages, where it forms in response to a range of different processes from igneous crystallisation to low-temperature early diagenesis. Due to its wide range of formation temperatures, its suitability and isotopic robustness for reliable U-Pb geochronology, dissolution/precipitation characteristics during overprint events, and widespread occurrence, it is one of the most valuable minerals for U-Pb geochronology leading to four-dimensional (4D) studies of many terranes. The formation environment of xenotime can be deduced from careful petrography and reliable U-Pb in-situ geochronology within a 4D framework. Further, xenotime is a physically robust mineral during sediment transport and may carry distinctive geochemical fingerprints, including age, to secondary environments.From published works, we review the U-Th-contents of well-characterised examples of xenotime formation to provide chemical fingerprints, which assist in identifying the xenotime formation environment. Although the U-Th characteristics of xenotime from all formation environments show considerable overlap, we make the following observations which may be distinctive of some ore formation environments: (i) hydrothermal xenotime formed from low salinity ore fluids (e.g. iron ore and orogenic gold deposits) trend to have the lowest U-contents ( < . 100. ppm U) and U/Th ( < . 4), in contrast to xenotime formed from higher salinity ore fluids (Sn-W and base metal deposits); (ii) xenotime associated with unconformity-related U-ores have the highest U-contents at U/Th. > . 10; (iii) diagenetic xenotime has the most variable and highest U/Th, whereas (iv) xenotime from Precambrian orogenic gold deposits has the least variable and lowest U/Th.Petrogenetic inferences from these observations for ore deposit research and exploration include: (i) support for the homogenising effect of the crustal scale of the fluid system in Precambrian orogenic gold deposits, and (ii) the potential for distinctive U-Th geochemical fingerprints for U ores and some Au ores. These characteristics may be reflected in detrital xenotime grains recovered from routine exploration sampling programs. 2017 Journal Article http://hdl.handle.net/20.500.11937/56941 10.1016/j.chemgeo.2017.08.016 Elsevier Science BV restricted |
| spellingShingle | McNaughton, Neal Rasmussen, B. Geochemical characterisation of xenotime formation environments using U-Th |
| title | Geochemical characterisation of xenotime formation environments using U-Th |
| title_full | Geochemical characterisation of xenotime formation environments using U-Th |
| title_fullStr | Geochemical characterisation of xenotime formation environments using U-Th |
| title_full_unstemmed | Geochemical characterisation of xenotime formation environments using U-Th |
| title_short | Geochemical characterisation of xenotime formation environments using U-Th |
| title_sort | geochemical characterisation of xenotime formation environments using u-th |
| url | http://hdl.handle.net/20.500.11937/56941 |