A H2O-in-zircon perspective on the heterogeneous water content of crust-derived magmas in southern Tibet

Meng, Juntong; Xia, Xiaoping; Ma, Lin; Jiang, Zhenzhen; Xu, Jian; Cui, Zexian; Yang, Qing; Zhang, Wanfeng; Le, Zhang

doi:10.1007/s11430-020-9790-1

Cited by 7 publications

(2 citation statements)

References 68 publications

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“…These characteristics suggest that the original magma has high water content (H 2 O > 4%). Inger and Harris (1993) found that the dehydration and melting of muscovite would lead to the increase of the Rb/Sr ratio and the decrease of Sr and Ba contents in the melt; the trend diagram of dehydration melting and water-fluxed melting was divided (Sylvester, 1998;Meng et al, 2021). From Figures 11A,B, it is seen that the Yaozhuang stock shows a good trend of Muscovite dehydration melting; the fluid formed by dehydration melting of water-bearing minerals in the crust leads to further melting of the rock (Weinberg and Hasalová, 2015).…”

Section: Implications For Mo Polymetallic Ore Prospectingmentioning

confidence: 99%

Discovery of Yaozhuang Stock and Deep Ore Prospecting Implication for the Western Mangling Orefield in North Qinling Terrane, Central China

Fan

Zhou

et al. 2022

Front. Earth Sci.

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In the western Mangling orefield, the molybdenum (Mo) polymetallic deposits are closely related to the ore-bearing porphyry stocks (individual outcrop size: <1 km2). In this study, we have discovered several granitic stocks at Yaozhuang. Systematic petrologic, zircon U-Pb-Hf isotope and whole-rock geochemical studies show that both the granitic stocks of porphyritic granite (157 ± 2 Ma) and the intruding monzogranite dike (153 ± 1 Ma) were emplaced in the Late Jurassic. These granitic stocks are characterized by high SiO2 (66.83–75.63 wt%), high K2O (4.15–5.05 wt%), high Al2O3 (12.90–16.93 wt%), and low MgO (0.06–0.73 wt%) and are metaluminous to weakly peraluminous, being highly fractionated I-A-type transition granites. The content of the total rare Earth element (ΣREE) of the porphyritic granite (139.6–161.7 ppm) is lower than that of the monzogranite (151.4–253.6 ppm). The porphyritic granite has weakly negative Eu anomalies (Eu/Eu* = 0.77–0.93), whereas the monzogranite has weakly positive Eu anomalies (Eu/Eu* = 0.97–1.21) and are more enriched in light rare Earth elements. Both of them are enriched in large ion lithophile elements (LILEs, e.g., K, Rb, and Ba) but depleted in high-field-strength elements (HFSEs, e.g., Nb, Ta, Ti, Zr, and Hf). The zircon εHf(t) values of all the samples range from −16.1 to −6.9, and the two-stage model ages (tDM2) are 1.78–2.16 Ga. The magma may have originated from partial melting of the lower crust (more than 40 km in depth) caused by mantle-derived magma underwelling. The plutons and stocks were emplaced into the intersection of the early EW-trending faults and the late (Yanshanian) NE-trending faults. The fertile magma with high water content (H2O > 4%) and high oxygen fugacity (Delta FMQ > 1.5) indicates that the Yaozhuang area has significant potential for porphyry Mo polymetallic ore discovery.

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Section: Implications For Mo Polymetallic Ore Prospectingmentioning

confidence: 99%

Discovery of Yaozhuang Stock and Deep Ore Prospecting Implication for the Western Mangling Orefield in North Qinling Terrane, Central China

Fan

Zhou

et al. 2022

Front. Earth Sci.

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“…Recently, Xia et al 51 developed a new reference material suite and an analytical procedure for the simultaneous measurement of H2O content and oxygen isotopes in zircon by secondary ion mass spectroscopy (SIMS). Subsequently, Xia et al 52 and Meng et al 53 suggested that zircon, similar to other NAMs, has the potential to characterize the hydrous status of its parental magma. Combined with chronological information, 34 zircon can provide more reliable evolutionary information for both extraterrestrial and terrestrial samples.…”

Section: Introductionmentioning

confidence: 99%

Atomic Spectroscopy

Xia¹

2022

At.Spectrosc.

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Water is perhaps the most important molecule in the solar system, and determining its origin and distribution in planetary interiors has significant implications for understanding the formation and evolution of planetary bodies. Zircon (present in both extraterrestrial and terrestrial samples) is a resistant and versatile accessory mineral, and its water content has the potential to characterize the hydrous status of zircon-crystallizing magma. However, the hydrous status can be altered by magma fractionation, mixing, or degassing. Although hydrogen isotopes of zircon can help to trace these processes, the lack of relevant microanalytical technology and reference materials has hindered significant breakthroughs in this area. In this study, we employed an analytical technique of secondary ion mass spectrometry (SIMS) to simultaneously measure the hydrogen isotopes of zircon and their H2O content. The homogeneity test of hydrogen isotope and the H2O content of the potential reference materials (D15395, D15814, and Temora 2) were conducted by measuring the 16 OD and 16 O 1 H signals (using SIMS) in a conventional peak-hopping mono-collector mode with electron-multiplier (EM) detectors. SIMS results show that the apparent external precision (1SD) of hydrogen isotope of large grains D15395 and D15814 are 16‰ and 22‰, which is comparable with their internal error and theoretical precision according to counting statistics, indicating that they are sufficiently homogenous at the micrometer sampling level in terms of hydrogen isotopes. However, zircon Temora 2 shows a much worse external precision (83‰, 1SD) and an obvious negative correlation between hydrogen isotope and H2O content, hence it is not suitable to be used as reference material for hydrogen isotope. Both hydrogen isotope and H2O content of three samples were also measured using a continuous-flow thermal conversion elemental analyzer operating online with a mass spectrometer (TC/EA-MS). The homogeneous samples zircon D15395 and D15814 yielded recommended δD values of -87 ± 9‰ and -68 ± 2‰ (1SD) and H2O content of ~478 ppm and ~332 ppm, respectively. Additionally, H2O contents acquired by TC/EA-MS and SIMS (calibrated by FTIR determined standards) were consistent within a 10% error range, demonstrating the reliability of the SIMS H2O content calibration curve for zircon and the FTIR absorption coefficient used before.

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Mantle contributions to granitoids associated with Sn mineralization: Geochemical and isotopic evidence from the giant Dachang deposit, South China

Wang,

Shu,

Xia

et al. 2024

Geoscience Frontiers

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A H2O-in-zircon perspective on the heterogeneous water content of crust-derived magmas in southern Tibet

Cited by 7 publications

References 68 publications

Discovery of Yaozhuang Stock and Deep Ore Prospecting Implication for the Western Mangling Orefield in North Qinling Terrane, Central China

Discovery of Yaozhuang Stock and Deep Ore Prospecting Implication for the Western Mangling Orefield in North Qinling Terrane, Central China

Atomic Spectroscopy

Mantle contributions to granitoids associated with Sn mineralization: Geochemical and isotopic evidence from the giant Dachang deposit, South China

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