Zircon Hf-O isotope evidence for recycled oceanic and continental crust in the sources of alkaline rocks

Research Article| May 01, 2017 Zircon Hf-O isotope evidence for recycled oceanic and continental crust in the sources of alkaline rocks Yu-Sheng Zhu; Yu-Sheng Zhu 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China2University of Chinese Academy of Sciences, Beijing 100049, China Search for other works by this author on: GSW Google Scholar Jin-Hui Yang; Jin-Hui Yang * 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China2University of Chinese Academy of Sciences, Beijing 100049, China *E-mail: jinhui@mail.igcas.ac.cn Search for other works by this author on: GSW Google Scholar Jin-Feng Sun; Jin-Feng Sun 2University of Chinese Academy of Sciences, Beijing 100049, China Search for other works by this author on: GSW Google Scholar Hao Wang Hao Wang 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Search for other works by this author on: GSW Google Scholar Author and Article Information Yu-Sheng Zhu 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China2University of Chinese Academy of Sciences, Beijing 100049, China Jin-Hui Yang * 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China2University of Chinese Academy of Sciences, Beijing 100049, China Jin-Feng Sun 2University of Chinese Academy of Sciences, Beijing 100049, China Hao Wang 1State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China *E-mail: jinhui@mail.igcas.ac.cn Publisher: Geological Society of America Received: 07 Dec 2016 Revision Received: 08 Jan 2017 Accepted: 12 Jan 2017 First Online: 28 Jun 2017 Online Issn: 1943-2682 Print Issn: 0091-7613 © 2017 Geological Society of America Geology (2017) 45 (5): 407–410. https://doi.org/10.1130/G38872.1 Article history Received: 07 Dec 2016 Revision Received: 08 Jan 2017 Accepted: 12 Jan 2017 First Online: 28 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Yu-Sheng Zhu, Jin-Hui Yang, Jin-Feng Sun, Hao Wang; Zircon Hf-O isotope evidence for recycled oceanic and continental crust in the sources of alkaline rocks. Geology 2017;; 45 (5): 407–410. doi: https://doi.org/10.1130/G38872.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Post-orogenic and intraplate extensional alkaline rocks are believed to have formed by partial melting of metasomatized ultramafic rocks in the subcontinental lithospheric mantle. Their variable incompatible element abundances and radiogenic isotopic ratios reflect recycling of subducted oceanic or continental crustal material into their source reservoirs. However, whole-rock geochemical and Sr-Nd isotopic data do not well constrain the nature of this recycled crustal material because of complex petrogenetic processes, i.e., crustal assimilation, fractional crystallization, magma mixing, and post-magmatic alteration. Here we present an integrated study of in situ Hf-O isotopes in zircons from two Triassic alkaline complexes in the northeastern Sino-Korean craton, i.e., the Hekanzi and Saima alkaline complexes. The Hekanzi alkaline rocks have zircon εHf(t) values of −2.5 to +0.6 and sub-normal mantle δ18O (+3.8‰ to +5.4‰), indicating a component of high-temperature altered oceanic crust involved in their mantle source prior to magma generation. In contrast, the Saima alkaline rocks have extremely negative zircon εHf(t) (−11 to −14) and elevated δ18O (+7.1‰ to +8.4‰) values, suggesting continental crust recycled into their mantle source prior to magma generation. Our results show that the combined zircon Hf and O isotopes are powerful tracers to distinguish recycled continental crust from recycled oceanic crust and, importantly, provide compelling evidence for recycled continental crust in the sources of alkaline rocks. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.