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A-type granite shows unique geochemical characteristics and refers to specific formation conditions and tectonic environments, and therefore plays an important role in reconstructing orogenic events. In this paper, we systematically investigated the zircon U Pb, whole-rock geochemistry, in-situ zircon Hf, apatite trace elements, and in-situ Nd data of the Huanren monzogranite to discuss its petrogenesis and the tectonic evolution of Jiao-Li-Ji belt. The studied zircon and apatite grains show typical oscillatory zoning and subhedral texture as well as obvious internal structure without any fluid/mineral inclusions, referring to a magmatic origin. Therefore, zircon U Pb dating results suggest that the Huanren monzogranite was formed in the late Paleoproterozoic (1863–1842 Ma). The studied rocks show typical A-type granite affinities as high SiO 2 (64.54–69.06 wt%), Na 2 O + K 2 O (8.00–9.34 wt%), and Zr + Nb + Ce + Y (381–598 ppm) concentrations, and FeOT/(FeOT + MgO) (0.82–0.85) and 10000Ga/Al (2.37–2.65) ratios. Their high whole-rock Zr temperature (812–866 °C, generally >840 °C), and low whole-rock Sr (109–157 ppm), apatite Sr (43.4–79.3 ppm) contents, whole-rock Sr/Y (4.79–8.22) and apatite Sr/Y (0.014–0.033) ratios, combined with slightly depleted in-situ zircon Hf (−1.62 to +2.50) and in-situ apatite Nd (−3.22 to −1.65) isotopic compositions, and ancient zircon Hf two-stage model ages (T DM2 ; 2606–2351 Ma), apatite Nd-T DM2 (2576–2451 Ma), suggest that the studied rocks were formed by partial melting of Neoarchean to Paleoproterozoic granitic gneiss in a high temperature and low-pressure condition. The studied A-type granite, together with regional A-type granite and alkaline syenite in the North China Craton, record the post-collisional event between the Nangrim and Longgang blocks, which combined with coeval worldwide A-type granite magmatisms, representing a response of the initial breakup of Columbia supercontinent. [Display omitted] • The studied granite was emplaced at 1.86–1.84 Ga and showed an affinity of aluminous A-type granite. • The reworking of ancient granitic gneiss occurred in a post-collisional environment. • The worldwide coeval A-type granites recorded the initial breakup of the Columbia supercontinent. [ABSTRACT FROM AUTHOR]

• 1813–1789 Ma A-type granites were identified in southern NCC. • A-type granites originated from partial melting of TTG of Taihua Complex. • The A-type magmatism was in respond to the breakup of Columbia supercontinent in post-collisional setting. A-type granites are produced commonly in extensional settings and they are important proxies to track breakup of continent. Here we report systematic studies on geochronology and geochemical features of A-type granites in Songxian–Ruyang region, southern margin of the North China Craton (NCC), in order to constrain their petrogenesis and tectonic implications. Zircons from these granites show oscillatory zoning and high Th/U ratios (0.12 to 1.26), indicating a magmatic origin. LA–ICP–MS zircon U–Pb dating shows that they were emplaced at 1813 to 1789 Ma, indicating that they were formed in late Paleoproterozoic. Geochemically, these rocks are high in SiO 2 (67.51–74.42 wt%) and total alkalis (Na 2 O + K 2 O = 7.76–10.19 wt%), and low in MgO (0.09–1.31 wt%), CaO (0.09–1.11 wt%) and P 2 O 5 (0.12–0.26 wt%) contents, with negative Nb, Ta, Sr, P and Ti anomalies. They are characterized by high FeOT/(MgO + FeOT), 10000 Ga/Al ratios (1.57–3.15) and Zr + Nb + Ce + Y contents (566–835 ppm). They are also characterized by high calculated Zr saturation temperatures (892–918 °C), high Ti-in-zircon temperatures (693–912 °C) and metaluminous to weakly peraluminous natures, which are typical features of aluminous A-type granites, further belonging to the A 2 granites. The low zircon ε Hf (t) values (–13.8 to –8.6), along with the low whole rock ε Nd (t) values (–8.62 to –6.10) and low apatite ε Nd (t) values (–8.31 to –6.56), indicate that the Songxian–Ruyang A-type granites were derived from partial melting of the calc-alkaline tonalitic–trondhjemitic–granodioritic gneisses in Taihua Complex, and they were formed in post-collisional extensional setting. Combined with coeval regional granitoids, the south margin of the NCC is in a continuous extensional setting during 1.8–1.6 Ga, and the Songxian–Ruyang A-type granites can represent a response of the breakup of Columbia supercontinent. [ABSTRACT FROM AUTHOR]

This paper reports new whole–rock major– and trace–element and zircon U Pb and Hf O isotopic data for Early Cretaceous granitic rocks on Liaodong Peninsula, NE China, with the aim of constraining continental reworking in the northeastern North China Craton. On the basis of SiO 2 , MgO, and Sr contents and Sr/Y values, the rocks can be divided into three groups. The low–Mg adakitic rocks show zircon U Pb ages of (134–120 Ma), and high SiO 2 (67.11–71.14 wt%) and low MgO (0.53–0.62 wt%) contents, and high Sr (531–1108 ppm) contents, Sr/Y (29.3–132) ratios, with enriched Sr–Nd–Hf–O isotopic compositions, indicating an origin of thickened lower mafic crust. The high–Mg adakitic rocks show ages of (126–114 Ma) and are characterized by low SiO 2 (53.11–63.88 wt%) and high MgO (2.07–8.93 wt%) contents, and high Sr (391–1041 ppm) contents, Sr/Y (23.9–64.1) ratios, with relatively depleted Sr–Nd–Hf–O isotopic compositions, suggesting that they were derived from partial melting of delaminated lower mafic crust. The normal granitic rocks show ages of (127–121 Ma) and high SiO 2 (71.65–77.22 wt%) and low MgO (0.10–0.51 wt%) and Sr (12.1–309 ppm) contents, Sr/Y (0.89–24.5) ratios, with relatively depleted Sr–Nd–Hf–O isotopic compositions, suggesting an origin from lower mafic crust with normal crustal thickness. These constraints, combined with the regional occurrence of A–type granites, bimodal igneous rocks, and metamorphic core complexes, as well as the regional distribution of Mesozoic granitic rocks displaying a younging trend from southeast to northwest for the Jurassic rocks but a reverse trend for the Cretaceous rocks, recorded the roll–back of the Paleo–Pacific plate towards the Eurasian continental margin. [Display omitted] • Discovery of Early Cretaceous low– and high–Mg adakitic and normal granitic rocks on Liaodong Peninsula. • Reworking of lower crust with different properties occurred in Liaodong Peninsula. • The subducted Paleo–Pacific plate rolled back during Early Cretaceous. [ABSTRACT FROM AUTHOR]

Abstract: We present geochronological, geochemical, and Sr–Nd–Pb isotope data for late Mesozoic granitoids in southern Jilin province, northeastern China, with the aim of ascertaining the genesis of the granitoids, and further constraining the nature of the lower crust and Mesozoic tectonic evolution of the eastern North China Craton (NCC). The results of LA-ICP-MS zircon U–Pb dating for seven granitoid plutons (from northeast to southwest, the Liudaogou, Toudaogou, Xingfu, Ji''an, Yushulinzi, Lujiangchun, and Zhenjiang plutons) indicate that they formed in the Early Cretaceous (130–122Ma). The granitoids consist of granodiorite, monzogranite, syenogranite, and alkali feldspar granite. Geochemically, they have SiO2 =61.8–76.2%, MgO=0.04–3.27%, Mg# [100(Mg/(Mg+Fe2+)]=7–55, and Al2O3 =12.7–16.2%, and they are characterized by enrichment in light rare earth elements (LREEs) and large ion lithophile elements (LILEs, such as Rb, Cs, and K), and depletion in heavy rare earth elements (HREEs) and high field strength elements (HFSEs, such as Nb and Ta). Their initial 87Sr/86Sr ratios, ε Nd(t) values, and initial 206Pb/204Pb ratios range from 0.70627 to 0.71067 (except for one sample), −1.9 to −13.9, and 17.84 to 18.47, respectively. Compared with the Zhenjiang, Yushulinzi, Lujiangchun, and Ji''an plutons from the southwestern part of the study area [ε Nd(t)=−9.8 to −13.9 and TDM2 =1726–2058Ma], those from the northeastern part of the study area (the Xingfu, Toudaogou, and Liudaogou plutons) have relatively high ε Nd(t) values (−1.9 to −8.8), low TDM2 (1081–1641Ma). The Early Cretaceous granitoids with high SiO2 contents and low Mg# from the southwestern part of the study area, together with those with high SiO2 contents and low Mg# from the northeastern part of the study area, were possibly mainly derived from the partial melting of Paleoproterozoic lower crust, with a minor contribution from younger material. The latter granitoids, together with the Zhenjiang granodiorites from the southwestern part of the study area, may have formed via mixing between crust- and mantle-derived melts. The rock associations and geochemistry of the southern Jilin granitoids, together with the contemporaneous volcanic rocks in this area, indicate that they formed in an active continental margin setting associated with the oblique subduction of the Paleo-Pacific Plate beneath the Eurasian continent in the Early Cretaceous. [Copyright &y& Elsevier]

We report geochemical data of apatites from Mesozoic granitoids in the northeastern North China Craton (NCC), and discuss the relationship between apatite and whole-rock compositions with the aim of using apatite geochemical data to constrain granitoid petrogenesis. Measured Sr contents and Sr/Y ratios of apatites exhibit positive correlations with those of their host rocks, and ε Nd (t) values of apatites display a strong linear relationship with ε Hf (t) values of zircons in the granitoids. In addition, apatites exhibit similar rare-earth element (REE) distribution patterns with their host rocks, although apatites have much higher REE contents. Sr/Y–Y variation diagram for apatite is proposed to distinguish adakitic rock from non-adakitic. The REE patterns of apatites, together with other geochemical indexes, can also be used to discriminate highly fractionated granitoids from unfractionated I-type granite or other type granite. The geochemical and Nd isotopic compositions of apatites have well revealed the magma source of Mesozoic granitoids in the northeastern NCC. In conclusion, we highlight that apatite geochemistry reflects the whole-rock geochemical characteristics of granitoids and has the potential to track granite detritus. • Geochemical data of apatites from the Mesozoic granitoids in the NCC are reported. • Apatite REE patterns are governed by multiple factors. • Sr, Y contents and Sr/Y ratios in apatites can be used to identify adakitic rocks. • Apatite REE patterns can be used to identify highly fractionated I-type granitoids. [ABSTRACT FROM AUTHOR]