%0 Journal Article
%T Geochemical characteristics of the Changhai granitic gneisses in Southeast Liaoning Province, NE China: Implications for its protolith property and formed tectonic setting<br>辽东南长海地区花岗质片麻岩类的地球化学特征:对其原岩性质及形成环境的制约
%A MENG En
%A LIU FuLai
%A LIU JianHui
%A SHI JianRong
%A <br>孟恩
%A 刘福来
%A 刘建辉
%A 施建荣
%J 岩石学报
%D 2012
%I 
%X In this paper, we performed systematically petrological and geochemical studies on the granitic gneisses near the Changhai Town in the southeastern Liaoning Province. Our data placed constraints on their protolith and tectonic setting. The results showed that these granitic gneisses could be divided into two types, (sodium) Na-rich and (potassium) K-rich granitic gneisses. The former are mainly composed of biotite monzogneisses and biotite granodioritic gneisses, and their mineral compositions chiefly include plagioclase, quartz, biotite and K-feldspar, etc. The latter consist of granitic, monogranitic and mylonitic granitic geisses, the mineral compositions of which are mainly composed of K-feldspar, plagioclase, quartz and minor muscovite and biotite. Geochemical analyses indicate that the Na-rich granitic gneisses are characterized by high contents of SiO2, Na2O and Al2O3, enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), strong depletion in heavy rare earth elements (HREEs) and high field-strength elements (HFSEs), relative depletion in Ba and weak negative Eu anomaly. On the other hand, the K-rich granitic gneisses are peraluminous and show geochemical features of high contents of SiO2 and K2O, enrichments in LREEs and LILEs, and depletion in HREEs and HFSEs. However, compared to the Na-rich ones, the K-rich granitic gneisses exhibit moderate negative Eu anomaly, relatively weaker REEs fractionation and stronger depletion in HFSEs and Ba. These features suggest that the Na-rich granitic gneisses could be derived from the partial melting of intermediate-acid crustal materials, with some basaltic material involved in the source and their protolith could be the granodiorite formed at an active continental margin The formation of these Na-rich granitic gneisses could be related to the subduction of the pre-existent oceanic basin beneath the Nangrim Massif (or Jiao-Liao Massif). On the other way, the Na-rich granitic gneisses could originate by partial melting of the crust and their protolith could be alkaline granites in a collisional tectonic setting after subtraction and closure of the previous oceanic crust.
%K Granitic gneisses
%K Geochemistry
%K Sodium-rich
%K Potassium-rich
%K Protolith petrogenesis
%K Jiao-Liao-Ji Belt
%K Changhai<br>花岗质片麻岩
%K 地球化学
%K 富钠
%K 富钾
%K 胶-辽-吉带
%K 长海
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=E62459D214FD64A3C8082E4ED1ABABED5711027BBBDDD35B&cid=621CF755B1A341E5&jid=2013B5467E3054B1614CEC199353FCED&aid=E7275A8322C2772E7F3E81DE6E1AE365&yid=99E9153A83D4CB11&vid=D3E34374A0D77D7F&iid=9CF7A0430CBB2DFD&sid=B5888B223AC9BC2D&eid=D75E56D700503C25&journal_id=1000-0569&journal_name=岩石学报&referenced_num=0&reference_num=69