| Title | Early Cretaceous volcanic and sub-volcanic rocks in the Erlian Basin and adjacent areas, Northeast China: new geochemistry, geochronology and zircon Hf isotope constraints on petrogenesis and tectonic setting |
| Authors | Tang, Jianzhou Zhang, Zhicheng Ji, Zejia Chen, Yan Li, Ke Yang Jinfu Liu, Pingping |
| Affiliation | Peking Univ, MOE Key Lab Orogen Belts & Crustal Evolut, Beijing, Peoples R China Peking Univ, Sch Earth & Space Sci, Beijing, Peoples R China Chongqing Univ, Coll Resources & Environm Sci, Chongqing, Peoples R China |
| Keywords | Early Cretaceous volcanic and sub-volcanic rocks geochemistry petrogenesis tectonic setting Northeast China |
| Issue Date | 2019 |
| Publisher | INTERNATIONAL GEOLOGY REVIEW |
| Abstract | Early Cretaceous volcanic rocks are widely distributed in northeast China and being extensively observed recently. However, petrogenesis and tectonic setting of these volcanic rocks are still on debate. We present zircon U-Pb ages, whole-rock geochemistry and zircon Hf isotope for these volcanic and sub-volcanic rocks surrounding the Erlian Basin including basic-intermediate volcanic rocks, intermediate-felsic volcanic rocks, and dacites and trachyandesite from dikes. The zircon U-Pb dating results indicate that these rocks formed in the Early Cretaceous (146-129 Ma). The basic-intermediate volcanic rocks mainly consist of basaltic andesite, which are featured by low SiO2 concentrations (49.96-58.34 wt. %), high Mg-# values (54-37) and Co contents (17.85-25.98 ppm), and positive epsilon(Hf(t)) values (+7.11 to +13.87). Moreover, they show high La/Nb (1.79-2.87) and low La/Ba (0.02-0.08) ratios. Such features indicate that they were derived from partial melting of lithospheric mantle that had been modified by fluids. The intermediate-felsic volcanic rocks consist of trachydacite and andesite, which show medium SiO2 concentrations (58.31-66.44 wt. %), a wide range of Mg-# values (28-53) and with A(1)-type granites affinities. These features, along with slightly positive to negative epsilon(Hf(t)) values (+0.53 to -17.71), indicate that they originated from mixed magma of melted lower crust and mantle substances. Dacites from dikes are distinguished by high SiO2 concentrations (65.72-67.2 wt. %), negative epsilon(Hf(t)) values (-2.55 to -6.72) and old zircon Hf T-DM2 ages (1453-1653 Ma), suggesting they were generated by melting of Mesoproterozoic and Palaeoproterozoic crustal material. All of the investigated volcanic and sub-volcanic rocks exhibit geochemical signatures of extension setting. In combination with previous studies, we suggest the Early Cretaceous extension in northeast China is related to the collapse of thickened lithosphere after closure of the Mongol-Okhotsk Ocean and to the slab break off of the Mudanjiang Ocean. |
| URI | http://hdl.handle.net/20.500.11897/545909 |
| ISSN | 0020-6814 |
| DOI | 10.1080/00206814.2018.1517615 |
| Indexed | SCI(E) EI |
| Appears in Collections: | 造山带与地壳演化教育部重点实验室 地球与空间科学学院 |
