The δ¹⁸O of UST Quartz in Two Porphyry Deposits, China

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• 作者：Huanchun Qu ; Maoyu Sun and Pu Dong
• 刊名：Resource Geology
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：67
• 期：1
• 页码：109-115
• 全文大小：575K
• ISSN：1751-3928

文摘

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 δ¹⁸O_water 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.