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Unlike globally prevalent mineralization in cratonic margin, the Hengshan-Wutai-northern Taihang region (HWTR) represents a typical and rare intracratonic Au-polymetallic metallogenic belt, which is situated within the interior North China Craton (NCC), where voluminous Early Cretaceous magmatic suites provide critical insights into intracratonic metallogenic processes associated with magmatism. Here, we present zircon U-Pb geochronology, trace elements, and in-situ Lu-Hf isotopes on various magmatic rocks from the Laiyuan complex, which represents the largest and most compositionally diverse plutonic complex in the HWTR. Our new results, combined with previous whole-rock and zircon geochemical data, suggest that the Early Cretaceous magmatism were emplaced in two episodes: early magmatic event (including ultramafic-mafic rocks, intermediate-felsic granitoids and mafic enclaves) at ∼140–126 Ma, and late mafic diking event at ∼125–111 Ma. Their zircon Hf and whole-rock Sr-Nd isotopic data show different sources for their parent magmas. The early magma was originated predominantly from mafic lower crust, whereas the late magma was mainly derived from enriched lithospheric mantle. The Laiyuan high-K calc-alkaline granitoids exhibit adakitic signatures, e.g., high Sr/Y and low Y. Their trace element systematics, particularly (Sm/Yb) SN , Yb SN , and (La/Yb) N ratios, indicate generation by partial melting of a mafic lower crust under normal thickness ( 0.3, U/Yb > 0.5, Ba/Zr > 4, V/Y > 2) suggest that the parental melts retained magmatic Au-fertility during magmatic differentiations, with relative hydration states. Further analysis using zircon fertility discriminators (e.g., Eu/Eu* > 0.4, Yb/Dy > 4, 1000*(Eu/Eu*)/Y > 1, (Ce/Nd)Y > 0.01) indicates that the ultramafic-mafic rocks, diorites and monzogranites have a high potential for magmatic Au fertility.
Li et al. (Thu,) studied this question.