Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization
The Jurassic Gangdese arc hosts the giant Xietongmen (Xiongcun) porphyry CuAu magmatic-hydrothermal centre. In order to understand the tectonomagmatic framework of the arc and its controls on the origin and temporal-spatial distribution of porphyry mineralization we conducted extensive major and tra...
| Main Authors: | , , , , , , , , |
|---|---|
| Format: | Journal Article |
| Published: |
Elsevier Science BV
2017
|
| Online Access: | http://hdl.handle.net/20.500.11937/50974 |
| _version_ | 1848758581889859584 |
|---|---|
| author | Wang, R. Tafti, R. Hou, Z. Shen, Z. Guo, N. Evans, Noreen Jeon, H. Li, Q. Li, W. |
| author_facet | Wang, R. Tafti, R. Hou, Z. Shen, Z. Guo, N. Evans, Noreen Jeon, H. Li, Q. Li, W. |
| author_sort | Wang, R. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The Jurassic Gangdese arc hosts the giant Xietongmen (Xiongcun) porphyry CuAu magmatic-hydrothermal centre. In order to understand the tectonomagmatic framework of the arc and its controls on the origin and temporal-spatial distribution of porphyry mineralization we conducted extensive major and trace, and isotopic analysis on a suite of samples collected regionally. Geochemical variations were observed across the Jurassic arc from south to north, controlled by northward subduction of the Neo-Tethyan oceanic plate and overlying Lhasa lithosphere. In the frontal arc (latitude 29°-29.55°N), the magmas had high Ba/La and Ba/Th ratios, high eNd(t) (+3 to +7) values, and their zircons have high eHf(t) (+10 to +18) values, and heterogeneous O isotopic compositions (d18O=+3.6 to +6.6‰). The low titanium-in-zircon temperature and zircon saturation temperature (both average=~700°C) suggest that a greater flux of dehydration fluids from the subducting slab triggered partial melting of the mantle wedge in the southern arc. High zircon Eu/Eu* and Ce/Nd ratios (>0.4 and >20, respectively) indicate highly oxidized, fertile magmas, from which the Xietongmen porphyry CuAu deposit formed. In contrast, the interior arc (north of latitude 29.55°), close to the ancient Tibetan basement, shows low Ba/La and Ba/Th ratios, low eNd(t) (-0.1 to +2.5) and zircon eHf(t) (+2 to +12) values, and less heterogeneous zircon O isotopic compositions with higher d18O values. Higher titanium-in-zircon and zircon saturation temperatures (mostly >750°C) suggest that less water was involved during the partial melting of mantle wedge in this region. Low zircon Eu/Eu* and Ce/Nd ratios (mostly <0.4 and <20, respectively) point towards less oxidized magmatic conditions. We conclude that across-arc geochemical and fluid-flux variations controlled the formation and spatial distribution of Jurassic porphyry deposits in the Gangdese belt. |
| first_indexed | 2025-11-14T09:46:16Z |
| format | Journal Article |
| id | curtin-20.500.11937-50974 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T09:46:16Z |
| publishDate | 2017 |
| publisher | Elsevier Science BV |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-509742017-09-13T15:47:54Z Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization Wang, R. Tafti, R. Hou, Z. Shen, Z. Guo, N. Evans, Noreen Jeon, H. Li, Q. Li, W. The Jurassic Gangdese arc hosts the giant Xietongmen (Xiongcun) porphyry CuAu magmatic-hydrothermal centre. In order to understand the tectonomagmatic framework of the arc and its controls on the origin and temporal-spatial distribution of porphyry mineralization we conducted extensive major and trace, and isotopic analysis on a suite of samples collected regionally. Geochemical variations were observed across the Jurassic arc from south to north, controlled by northward subduction of the Neo-Tethyan oceanic plate and overlying Lhasa lithosphere. In the frontal arc (latitude 29°-29.55°N), the magmas had high Ba/La and Ba/Th ratios, high eNd(t) (+3 to +7) values, and their zircons have high eHf(t) (+10 to +18) values, and heterogeneous O isotopic compositions (d18O=+3.6 to +6.6‰). The low titanium-in-zircon temperature and zircon saturation temperature (both average=~700°C) suggest that a greater flux of dehydration fluids from the subducting slab triggered partial melting of the mantle wedge in the southern arc. High zircon Eu/Eu* and Ce/Nd ratios (>0.4 and >20, respectively) indicate highly oxidized, fertile magmas, from which the Xietongmen porphyry CuAu deposit formed. In contrast, the interior arc (north of latitude 29.55°), close to the ancient Tibetan basement, shows low Ba/La and Ba/Th ratios, low eNd(t) (-0.1 to +2.5) and zircon eHf(t) (+2 to +12) values, and less heterogeneous zircon O isotopic compositions with higher d18O values. Higher titanium-in-zircon and zircon saturation temperatures (mostly >750°C) suggest that less water was involved during the partial melting of mantle wedge in this region. Low zircon Eu/Eu* and Ce/Nd ratios (mostly <0.4 and <20, respectively) point towards less oxidized magmatic conditions. We conclude that across-arc geochemical and fluid-flux variations controlled the formation and spatial distribution of Jurassic porphyry deposits in the Gangdese belt. 2017 Journal Article http://hdl.handle.net/20.500.11937/50974 10.1016/j.chemgeo.2017.01.010 Elsevier Science BV restricted |
| spellingShingle | Wang, R. Tafti, R. Hou, Z. Shen, Z. Guo, N. Evans, Noreen Jeon, H. Li, Q. Li, W. Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization |
| title | Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization |
| title_full | Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization |
| title_fullStr | Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization |
| title_full_unstemmed | Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization |
| title_short | Across-arc geochemical variation in the Jurassic magmatic zone, Southern Tibet: Implication for continental arc-related porphyry CuAu mineralization |
| title_sort | across-arc geochemical variation in the jurassic magmatic zone, southern tibet: implication for continental arc-related porphyry cuau mineralization |
| url | http://hdl.handle.net/20.500.11937/50974 |