Fertility and longevity of hydrothermal systems are key parameters required to improve our ability in predicting new deposits and directly extracting metals from metalliferous fluids. Reconstructing evolutional trajectories of metalliferous fluids with high temporal resolution is critical for pushing our understanding forward, but this is inevitably challenging because traditional approaches for obtaining this information either have poor temporal resolution and/or bear considerable uncertainties. We present a novel approach (translating texture-controlled information to temporal patterns) to reconstruct the thermal and isotopic history of the Weilasituo vein-type tin deposit (Inner Mongolia, China) at the millennial scale. In situ oxygen isotope thermometry of paragenetically constrained quartz and cassiterite reveals that tin deposition was accompanied by gradual cooling of pure magmatic fluids from ~500 °C to ~390 °C at lithostatic conditions, while fluid mixing and/or water-rock interaction were not required. The system then transitioned to hydrostatic conditions and permitted penetration of meteoric water and further cooling. Aluminum diffusion in quartz chronometry yields time scales of ~50 k.y., ~5 k.y., and ~200 k.y. for pre-, syn-, and post-ore stages, respectively. Our results highlight that the magmatic-hydrothermal system did not form ore minerals for most of its lifetime, with mineralization occurring only briefly (i.e., <5% of its lifetime). Hence, the rates and efficiency of ore formation may need significant revision. For magmatic-hydrothermal systems with felsic magmas being stored at high crystallinity after extensive volatile exsolution, the efficiency of scavenging metals from melts to fluids critically controls their fertility. To directly extract metals from metalliferous fluids, the key is targeting systems with a high degree of magma crystallization (e.g., higher metal contents in fluids) in warm crust (e.g., able to sustain long-lived systems).

The oxygen (O) and neodymium (Nd) isotopic composition of monazite provides an ideal tracer of metamorphism and hydrothermal activity. Calibration of the matrix effect and monitoring of the external precision of monazite O–Nd isotopes with microbeam techniques, such as secondary ion mass spectrometry (SIMS) and laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICPMS), require well-characterized natural monazite standards for precise microbeam measurements. However, the limited number of standards available is impeding the application of monazite O–Nd isotopes. Here, we report on the RW-1 monazite as a potential new working reference material for microbeam analysis of O–Nd isotopes. Microbeam measurements by electron probe microanalysis (EPMA), SIMS, and LA-MC-ICPMS at 10–24 µm scales have confirmed that it is homogeneous in both elemental and O–Nd isotopic compositions. SIMS measurements yield δ¹⁸O values consistent, within errors, with those obtained by laser fluorination techniques. Precise analyses of Nd isotope by thermal ionization mass spectrometry (TIMS) are consistent with mean results of LA-MC-ICPMS analyses. We recommend δ¹⁸O = 6.30‰ ± 0.16‰ (2SD) and ¹⁴³Nd/¹⁴⁴Nd = 0.512282 ± 0.000011 (2SD) as being the reference values for the RW-1 monazite.

The Neoproterozoic Arabian‐Nubian Shield (ANS) is the best‐preserved and the largest exposed Neoproterozoic juvenile crust on Earth. While the lithology and early Sr and Nd isotopic data demonstrate that the ANS crust is overwhelmingly juvenile, pre‐ANS old zircons have been increasingly recognized in the ANS igneous and sedimentary rocks, casting doubt on the “juvenility” of the ANS crust. In order to understand the origin of the old continental materials in the ANS and its roles in generation of juvenile oceanic arcs, we carry out for the first time an integrated in situ analysis of zircon U‐Pb age and Hf‐O isotopes for greywacke and felsic volcanic cobble samples from the Atud Formation in the Eastern Desert of northwestern part of the ANS. Our data indicate that the Atud Formation was deposited between ca. 720 and 700 Ma, concurrent with the production of oceanic arcs in the ANS. The Atud greywacke was derived from the erosion of a proximal arc terrane that contains numerous old continental crust materials. We identify for the first time a 755 Ma felsic volcanic cobble from the Atud Formation that is derived from old continental materials during juvenile crust production, suggesting presence of an old continental crust substrate that underlies the ANS. Our work demonstrates that reworking of old continental crust played important roles in generation of oceanic arcs in the northwestern ANS that is likely much less juvenile than previously thought. Thus, the crustal growth rates calculated based on estimates of temporal island arc development need to be revised.