Abstract
This paper reports new zircon LA–ICP–MS U–Pb and Hf isotope data, and whole-rock major and trace element data for Late Permian to Early Triassic intrusive rocks in the Yanbian area, NE China. These data provide new insights into the timing of the final subduction of the Paleo-Asian Ocean beneath the North China Craton. The zircon U–Pb age data indicate that a suite of Late Permian to Early Triassic intrusive rocks related to subduction is present within the Yanbian area. The Late Permian intrusive rocks consist of diorites while the Early Triassic granites and hornblende gabbros constitute a geochemically bimodal igneous rock association. Furthermore, the Early Triassic granites show the geochemical characteristics of shoshonitic rocks. All the rocks are characterized by enrichment in LILEs and LREEs, and depletion in HREEs and HFSEs, suggesting they formed in a subduction setting. Zircons from the Early Triassic gabbros have εHf(t) values and TDM2 ages of +7.6 to +10.7 and 735–1022 Ma, respectively, suggesting that they formed from a primary magma generated by the partial melting of lithospheric mantle material that had been previously modified by subduction-related fluids. The Late Permian diorites have εHf(t) values and TDM2 ages of +0.5 to +9.5 and 853 to 1669 Ma, respectively, while they have high contents of Al2O3, Fe2O3, and low contents of SiO2, Cr, and Ni, indicating Late Permian diorites should derive from the mantle and are influenced by some crustal material. Early Triassic granitic rocks have a wide range of εHf(t) values and TDM2 ages of −4.8 to +9.4 and 852 to 2136 Ma, respectively. Their zircons imply that the Early Triassic granites could be mainly derived from partial melting of the crust, with minor contribution of the crustal material of an ancient crust. The Early Triassic bimodal intrusive rocks in Yanbian area, combined with the regional geologic information; therefore, record a final post-subduction extensional environment due to the break-off of the previously subducted slab.
Highlights
The Central Asian Orogenic Belt (CAOB) underwent a long history from the breakup of Rodinia Central AsianOrogenic underwent history from the breakupRodinia to theThe convergence of Pangea andBelt its (CAOB)evolution is related atolong the opening, subduction, andof closure of to the convergence of Pangea and its evolution is related to the opening, subduction, and closure the Paleo-Asian Ocean between Neoproterozoic and Late Paleozoic times [1,2,3,4]
Evolution is related atolong the opening, subduction, andof closure of to the convergence of Pangea and its evolution is related to the opening, subduction, and closure the Paleo-Asian Ocean between Neoproterozoic and Late Paleozoic times [1,2,3,4]
The LA–ICPMS zircons U–Pb data (FN25 and B4117), zircon Hf isotope data (B4117, FN25, B4135, N-8) and whole-rock major and trace elements for the intrusive rocks are listed in Tables 1 and 2, respectively
Summary
The Central Asian Orogenic Belt (CAOB) underwent a long history from the breakup of Rodinia. Craton (Figure 1) [4,5,6,7] It was due formed byclosure long-lived subduction, continental and continent-arc-continent collision to the of the. Itofremains debated on whether been studied the easternmost part of the CAOB It remains debated on whether the final suture the final suture location of Paleo-Asian Ocean extends to Yanbian area at the eastern termination of location ofsummary, Ocean extends to Yanbian area atevolution the eastern. Earlypetrological, Triassic intrusive rocks in the area, data the Yanbian area, to constrain theintrusive final tectonic in the Helong area, the Yanbian area, to constrain the final tectonic evolution stage of the easternmost evolution stage of the easternmost CAOB and shed new light on the timing of the final closure of the and shed new light on the timing of the final closure of the Paleo-Asian Ocean
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
