Petrogenesis and tectonic significance of Paleoproterozoic meta-mafic rocks from central Liaodong Peninsula, northeast China: Evidence from zircon U–Pb dating and in situ Lu–Hf isotopes, and whole-rock geochemistry

Provenance and tectonic setting of the Paleoproterozoic metasedimentary rocks from the Liaohe Group, Jiao-Liao-Ji Belt, North China Craton: Insights from detrital zircon U–Pb geochronology, whole-rock Sm–Nd isotopes, and geochemistry

“…However, there remain considerable controversies concerning the tectonic evolution of the JLJB (e.g., Zhao and Zhai, 2013;Zhai and Santosh, 2013). Some researchers believe that it formed by closure of an intra-continental rift (Zhang and Yang, 1988;Sun et al, 1993Sun et al, , 1996Palmer, 1995, 2002;Luo et al, 2004Luo et al, , 2008Hao et al, 2004;Li et al, 2005Li et al, , 2006Li et al, , 2011Li et al, , 2012Li and Zhao, 2007;Tam et al, 2011Tam et al, , 2012a, whereas others suggest that it is a Paleoproterozoic arc-continent collisional belt (Bai, 1993;Zhang, 1994;Bai and Dai, 1998;He and Ye, 1998;Faure et al, 2004;Lu et al, 2006;Meng et al, 2014;Li and Chen, 2014;Peng et al, 2014;Li et al, 2015). In order to decipher the nature and evolution of the JLJB, previous investigations laid great emphasis on the geochemistry of the volcanics (Meng et al, 2014;Li and Chen, 2014) or granitoids (Hao et al, 2004;Li et al, 2006), geochronology of the volcano-sedimentary sequence (Luo et al, 2004(Luo et al, , 2008Lu et al, 2008;Wan et al, 2006;Li et al, 2015) or granitoids (Lu et al, 2004a,b;Yang et al, 2007;Li and Zhao, 2007), metamorphism …”

Hadean detrital zircon in the North China Craton

“…The two blocks are underlain by the Archean basement (Liu et al, 1992;Song et al, 1996;Wu et al, 1997Wu et al, , 2005. The NE-trending Paleoproterozoic JLJB is composed of deformed sedimentary and volcanic successions and felsic-mafic intrusions that were metamorphosed to greenschist-amphibolite facies at~1.9 Ga as shown in Figure 1 (Luo et al, 2004;Li et al, 2005;Lu et al, 2006;Li and Zhao, 2007;Luo et al, 2008;Meng et al, 2014;Li et al, 2015aLi et al, , 2015b. The sedimentary and volcanic successions are called the Macheonayeong Group in North Korea , the Liaohe Group in the Liaodong Peninsula , the Laoling and Ji'an Groups in southern Jilin (Lu et al, 2006), and the Fenzishan and Jingshan Groups in the Shandong Peninsula (Tam et al, 2011).…”

“…The oldest zircon might be identified as (1) a trapped zircon entrained in the igneous rocks or (2) a detrital zircon from the sedimentary rocks. Wang et al (2011), Meng et al (2014, and presented detailed zircon U-Pb geochronological and LuHf isotopic studies on the meta-mafic rocks. They classified the zircons into three groups, one with a metamorphic origin (~1.9 Ga), another with a typical magmatic origin (2.0-2.2 Ga), and the remaining with a magmatic origin but with older ages (2.45-2.59 Ga).…”

“…In addition, the protoliths of the metasedimentary rocks in the Liaohe Group should be deposited before the regional tectonic-metamorphic event at~1.9 Ga (Luo et al, 2004;Li and Zhao, 2007;Luo et al, 2008;Xie et al, 2011;Li and Chen, 2014;Li et al, 2015aLi et al, , 2015b. The metamorphic age is well constrained by the evidence: (a) the 40 Ar/ 39 Ar age of 1896 ± 7 Ma for biotites from a main detachment shear zone in the Liaohe Group (Yin and Nie, 1996), (b) the concordant U-Pb age of~1.9 Ga for the metamorphic overgrowth of zircons from the metasedimentary rocks (LA-ICP-MS method) (Luo et al, 2004(Luo et al, , 2008Li et al, 2015b), (c) the age of 1914 ± 13 Ma for the metamorphic overgrowth of zircons from the gneissic granites using the SHRIMP technique (Li and Zhao, 2007) Meng et al (2014) and Li and Chen (2014) obtained a concordant U-Pb age of~1.9 Ga for the metamorphic zircons from the meta-mafic rocks, which were interpreted as the age of peak metamor- phism of the Liaohe Group during collisional processes. Therefore, obviously, the Dashiqiao Formation should be deposited before~1.9 Ga, which corresponds to the regional metamorphic event.…”

Paleoproterozoic Multiple Tectonothermal Events in the Longshoushan Area, Western North China Craton and Their Geological Implication: Evidence from Geochemistry, Zircon U–Pb Geochronology and Hf Isotopes

“…The samples of the metagabbro have low SiO 2 and REEs content, high MgO, Mg#, Ni and Cr content and have no correlation in the diagrams of Nb/La vs. SiO 2 (Supplementary Materials Figure S1), indicating that the rocks did not experience substantial crustal contamination during magmatic evolution [68][69][70]. This interpretation is also supported by the following lines of evidence: (1) The metagabbro has similar zircon εHf(t) values and common features of most major and trace elements (Figures 4 and 5a,b); (2) Lu/Yb ratios of our samples generally range from 0.14-0.15, which is consist with that of mantle-derived magmas (0.14-0.15) and is lower than that of continental crust (0.16-0.18) [71]; and (3) absence of ancient captured zircons does not support significant crustal contamination [72].…”