[Objective] Apatite is a common accessory mineral, widely distributed in various types of rocks. Its U-Pb age, trace element (especially REE, Th, U, and Sr) and Sr-Nd isotopic composition can provide important isotopic geochemical information on chronology and magmatism. However, the study of its geochemical behavior at different metamorphic levels during orogenesis remains unclear. As a typical continent-to-continent collisional orogenic belt in the Paleoproterozoic, the Trans-North China Orogen (TNCO) has recorded an integrated metamorphic sequence ranging from greenschist, amphibolite to granulite facies, so it is an ideal area to study the geochemical properties of apatite during the various grades of metamorphism involving the orogenic process. [Methods] In this study, we systematically collected metabasic samples that experienced different metamorphic grades, including greenschist, amphibolite and mafic granulite in the Wutai-Hengshan area of the TNCO. We carried out detailed petrographic observations and conducted geochemical analysis on those apatite grains from metabasic rocks with different metamorphic grades. [Results] Our results show that the apatite grains from the greenschist samples contain both types of magmatic and metamorphic origin. The apatite grains from amphibolite samples are mainly metamorphic origin. By contrast, those grains from the granulite samples are intimately related to the crustal anatexis, exhibiting geochemical characteristics of magmatic origin apatite. [Conclusion] This study shows that the trace element variation of apatite can clearly reflect the influence of metamorphic grades, crustal anatexis and the coexisting rock-forming minerals with the variation of temperature and pressure conditions during metamorphism. [Significance] The new results of this study provide new constraints on our understanding of the element migration and geochemical balance within the apatite during the orogeny.
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