Cenozoic lithospheric architecture and metallogenesis in Southeastern Tibet

Highlights

• Zircon LuHf isotopic mapping reveals distinct lithospheric domains in southeast Tibet.

• Zircon ε_Hf values distinguish magmatism associated with porphyry Cu-Mo-Au, orogenic-Au and rare earth element deposits.

• The juvenile domains correlate with low seismic velocity (−2% to −6%) and fertile mantle signature (Mg# ~89).

Abstract

Ore systems are located in zones of enhanced and focused heat and fluids flux within the lithosphere. In order to target deep ore deposits under cover, a better understanding of lithospheric architecture is essential, especially in relation to magmatism and fluids. Here we attempt an integrated approach using zircon LuHf isotopic mapping (455 samples with 5049 zircon analyses, including 1021 new data), combined with whole-rock geochemistry and isotopes of mantle-derived mafic rocks, high-resolution seismic tomography from 325 seismic stations and new thermochemical modelling, to establish the lithosphere architecture in southeastern Tibet. The integrated data suggest lithospheric refertilisation accompanied by heat flux from the asthenosphere, and also reveal the evolutionary pathway of the volatile components. The approach adopted in our study can be used in exploration for porphyry CuAu, orogenic-Au and rare earth element deposits in Southeastern Tibet, and illustrate the usefulness of lithosphere-architecture mapping as a useful tool for mineral exploration.