Multistage metallogeny and tectonic evolution in eastern NE China and adjacent Russian Far East: geochronology, geochemistry, and Sr-Nd-Hf isotope perspectives

Abstract

ABSTRACT A wide variety of deposit types formed in the late Palaeozoic-Mesozoic of eastern NE China and adjacent Russian Far East of the eastern Central Asian Orogenic Belt (CAOB). However, outstanding questions remain on the (1) number of magmatic and metallogenic phases, and their respective space–time distribution; (2) geochemical (incl. isotopic) signature and fertility of each magmatic phase; and (3) tectonic link with these magmato-metallogenic events. We present new data (zircon U-Pb dating, geochemistry, and Sr-Nd isotopes) on the Yangjingou W and Xiaoxi’nancha Au-Cu deposits, and compile published data from major ore deposits in the region. We have newly summarized four magmato-mineralization phases: (1) Middle Permian (ca. 273–259 Ma) Cu-Au-Pb-Zn, (2) Latest Permian-Early Triassic (ca. 253–247 Ma) W-Cu-Mo-Au, (3) Earliest-Middle Jurassic (ca. 201–162 Ma) Mo-Au-Fe-W-Pb-Zn, and (4) Cretaceous (ca. 129–83 Ma) W-Sn-Mo-Cu-Au mineralization. Cretaceous ore-causative granitoids are mainly I-type arc-related, whereas those for the three older mineralization phases are largely adakite-like or adakite-normal arc transitional. These granitoids were mostly derived from partial melting of juvenile crust, and to a lesser extent from a mixture of juvenile and ancient crust. We propose that the Middle Permian subduction of the Paleo-Asian and Panthalassa oceans formed the Au/Cu-Pb-Zn skarn and cryptoexplosive breccia-hosted Pb-Zn ± Ag deposits. Subsequently, the latest Permian-Early Triassic Paleo-Asian Ocean closure likely formed the porphyry-skarn Cu-Mo, orogenic Au, and vein-type W deposits in the Songliao and eastern Liaoyuan terranes. In the Early-Middle Jurassic, Paleo-Pacific subduction may have formed the Jiapigou orogenic Au belt and the Fe-polymetallic skarn deposits in the northern Songliao terrane, as well as porphyry Mo deposits along the Mudanjiang fault. Subsequently, Cretaceous W-Sn-Au-Cu metallogeny was controlled by Paleo-Pacific subduction rollback, and in the Russia Far East by partial melting of redox accretionary complexes.