Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes
Single crystal in situ Sr and Nd isotopic analysis of apatite permits more accurate interrogation of a variety of geoscience questions, including provenance, petrogenesis, and ore system evolution. However, the degree to which the apatite Sr and Nd isotopic systems remain closed under extended low-t...
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| Format: | Journal Article |
| Language: | English |
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AMER GEOPHYSICAL UNION
2019
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| Online Access: | http://purl.org/au-research/grants/arc/DP160102427 http://hdl.handle.net/20.500.11937/90784 |
| _version_ | 1848765427122962432 |
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| author | Cao, Mingjian Evans, Noreen Qin, K. Danišík, Martin Li, G. McInnes, Brent |
| author_facet | Cao, Mingjian Evans, Noreen Qin, K. Danišík, Martin Li, G. McInnes, Brent |
| author_sort | Cao, Mingjian |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Single crystal in situ Sr and Nd isotopic analysis of apatite permits more accurate interrogation of a variety of geoscience questions, including provenance, petrogenesis, and ore system evolution. However, the degree to which the apatite Sr and Nd isotopic systems remain closed under extended low-temperature hydrous conditions is not well constrained. Granitoids at the Baogutu deposit in NW China contain veins of low-temperature H2O-rich epistilbite and thus provide an excellent opportunity to evaluate isotopic system integrity under low-temperature hydrous conditions. Apatite from the Late Carboniferous diorite and granodiorite porphyry show variable (87Sr/86Sr)i ratios (0.7042 to 0.7062) but restricted εNd(t) values (+7.0±0.4 and +6.5±0.4, 1σ). The apatite Sr isotope signatures are transitional between whole rock (0.7035) and vein epistilbite (~0.7062), indicating apparent incorporation of radiogenic Sr from the epistilbite-related hydrothermal fluid into the igneous apatite, whereas εNd values closely match those of the whole rock (+6.9±0.2 and +6.5±0.2, 1σ) and epistilbite (+6.2±0.2, 1σ). Obvious metasomatic textures of apatite were revealed by cathodoluminescence images. The 260 to 300°C formation temperatures for earlier quartz-sulfide veins and chlorite alteration and homogenization temperature (~190°C) of fluid inclusions in epistilbite-calcite vein calcite constrain the temperature of the later epistilbite-related hydrothermal fluid to 190 to 260°C. These results indicate that Sr and likely Nd isotopes in apatite are mobile under low-temperature (<300°C) hydrous conditions and implies that Rb-Sr signatures in apatite from hydrothermally altered rocks reveal the presence and characteristics of modifying fluids. |
| first_indexed | 2025-11-14T11:35:04Z |
| format | Journal Article |
| id | curtin-20.500.11937-90784 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T11:35:04Z |
| publishDate | 2019 |
| publisher | AMER GEOPHYSICAL UNION |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-907842023-04-20T05:07:54Z Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes Cao, Mingjian Evans, Noreen Qin, K. Danišík, Martin Li, G. McInnes, Brent Science & Technology Physical Sciences Geochemistry & Geophysics in situ apatite Sr-Nd isotopes LA-MC-ICPMS zircon (U-Th) He dating apatite metasomatic alteration low-temperature hydrous condition Baogutu porphyry Cu deposit PORPHYRY CU DEPOSIT RARE-EARTH-ELEMENTS I-TYPE GRANITOIDS WESTERN JUNGGAR TRACE-ELEMENT U-PB DISSOLUTION-REPRECIPITATION HYDROTHERMAL TRANSPORT CHINA CONSTRAINTS BAOGUTU Single crystal in situ Sr and Nd isotopic analysis of apatite permits more accurate interrogation of a variety of geoscience questions, including provenance, petrogenesis, and ore system evolution. However, the degree to which the apatite Sr and Nd isotopic systems remain closed under extended low-temperature hydrous conditions is not well constrained. Granitoids at the Baogutu deposit in NW China contain veins of low-temperature H2O-rich epistilbite and thus provide an excellent opportunity to evaluate isotopic system integrity under low-temperature hydrous conditions. Apatite from the Late Carboniferous diorite and granodiorite porphyry show variable (87Sr/86Sr)i ratios (0.7042 to 0.7062) but restricted εNd(t) values (+7.0±0.4 and +6.5±0.4, 1σ). The apatite Sr isotope signatures are transitional between whole rock (0.7035) and vein epistilbite (~0.7062), indicating apparent incorporation of radiogenic Sr from the epistilbite-related hydrothermal fluid into the igneous apatite, whereas εNd values closely match those of the whole rock (+6.9±0.2 and +6.5±0.2, 1σ) and epistilbite (+6.2±0.2, 1σ). Obvious metasomatic textures of apatite were revealed by cathodoluminescence images. The 260 to 300°C formation temperatures for earlier quartz-sulfide veins and chlorite alteration and homogenization temperature (~190°C) of fluid inclusions in epistilbite-calcite vein calcite constrain the temperature of the later epistilbite-related hydrothermal fluid to 190 to 260°C. These results indicate that Sr and likely Nd isotopes in apatite are mobile under low-temperature (<300°C) hydrous conditions and implies that Rb-Sr signatures in apatite from hydrothermally altered rocks reveal the presence and characteristics of modifying fluids. 2019 Journal Article http://hdl.handle.net/20.500.11937/90784 10.1029/2019JB018085 English http://purl.org/au-research/grants/arc/DP160102427 AMER GEOPHYSICAL UNION unknown |
| spellingShingle | Science & Technology Physical Sciences Geochemistry & Geophysics in situ apatite Sr-Nd isotopes LA-MC-ICPMS zircon (U-Th) He dating apatite metasomatic alteration low-temperature hydrous condition Baogutu porphyry Cu deposit PORPHYRY CU DEPOSIT RARE-EARTH-ELEMENTS I-TYPE GRANITOIDS WESTERN JUNGGAR TRACE-ELEMENT U-PB DISSOLUTION-REPRECIPITATION HYDROTHERMAL TRANSPORT CHINA CONSTRAINTS BAOGUTU Cao, Mingjian Evans, Noreen Qin, K. Danišík, Martin Li, G. McInnes, Brent Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes |
| title | Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes |
| title_full | Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes |
| title_fullStr | Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes |
| title_full_unstemmed | Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes |
| title_short | Open Apatite Sr Isotopic System in Low-Temperature Hydrous Regimes |
| title_sort | open apatite sr isotopic system in low-temperature hydrous regimes |
| topic | Science & Technology Physical Sciences Geochemistry & Geophysics in situ apatite Sr-Nd isotopes LA-MC-ICPMS zircon (U-Th) He dating apatite metasomatic alteration low-temperature hydrous condition Baogutu porphyry Cu deposit PORPHYRY CU DEPOSIT RARE-EARTH-ELEMENTS I-TYPE GRANITOIDS WESTERN JUNGGAR TRACE-ELEMENT U-PB DISSOLUTION-REPRECIPITATION HYDROTHERMAL TRANSPORT CHINA CONSTRAINTS BAOGUTU |
| url | http://purl.org/au-research/grants/arc/DP160102427 http://hdl.handle.net/20.500.11937/90784 |