The δ18O of UST Quartz in Two Porphyry Deposits,China |
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| Authors: | Huanchun Qu Maoyu Sun Pu Dong |
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| Institution: | 1. Institute of Geology, Chinese Academy of Geological Sciences, Beijing;2. School of Earth Sciences and Resources, China University of Geosciences (Beijing), Beijing;3. School of Humanities and Economic Management, China University of Geosciences (Beijing), Beijing, China |
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| Abstract: | The unidirectional solidification textures (UST) quartz is generally thought to form from fluids exsolved from shallow intrusions and/or magma chambers, but such an idea is still poorly constrained from the evidence of stable isotopes. In this study, we report for the first time the δ18O of quartz that shows UST from the Qulong Cu–Mo and the Yechangping Mo porphyry deposits in China. The analysis results show that the UST quartz samples from the Qulong deposit have δ18O values ranging from +6.2 ‰ to +7.6 ‰, which are similar to that of quartz phenocrysts (+6.7 ‰ to +7.8 ‰). In contrast, the UST quartz samples from the Yechangping porphyry Mo deposit yield a high δ18O value (+10.0 ‰). The δ18Owater value of Yechangping UST quartz (+8.5 ‰) is also higher than that of Qulong (+4.6 ‰ to +5.8 ‰). Hydrothermal biotite from potassic alteration and sericite from early phyllic alteration at Qulong have similar δ18O values to UST quartz, suggesting the involvement of magmatic fluids during this stage of deposit evolution. |
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| Keywords: | fluid inclusions oxygen isotope porphyry deposit quartz UST |
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