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Figure S1: Photographs (A) and photomicrographs (B) of Weilasituo ZK granites. Figure S2: Photographs of Weilasituo ZK granites. Figure S3: Photomicrographs of Weilasituo (A–C) BD granites and (D–I) ZK granites. Figure S4: Photomicrographs of (A) Damuchu quartz monzonite porphyry and (B) Baocun granodiorites. Figure S5: Photomicrographs of Zalute (A) quartz diorite and (B) monzogranite. Table S1: LA-ICP-MS U-Pb zircon data of the Cretaceous HSGs from the SGXRMB. Table S2: Major (wt%) and trace (ppm) elements of the Cretaceous HSGs from the SGXRMB. Table S3: Whole-rock Sr-Nd-Hf isotopic compositions of the Cretaceous HSGs from the SGXRMB. Table S4: Zircon Hf-O isotopic compositions of the Cretaceous HSGs from the SGXRMB.

In this study, we undertook zircon U–Pb dating and Hf isotopic and whole-rock geochemical analysis of Mesozoic granites from the Zhalantun and Arxan areas of the Great Xing’an Range, northeastern China. Zircon U–Pb dating of four samples indicates they formed in the Early Cretaceous (ca. 140.7–130.0 Ma). Geochemically, the samples have high silica (74.00–77.29 wt.%) and total alkali (8.52–8.90 wt.%) and low CaO (0.21–0.71 wt.%), MgO (0.06–0.48 wt.%), and P2O5 (0.01–0.06 wt.%) contents and exhibit the weakly peraluminous (A/CNK = 0.98–1.06) and high-K calc-alkaline characteristics, with highly differentiated I-type granite affinities (differentiation index = 93.19–96.93). The studied granites are enriched in light rare earth and large ion lithophile elements and depleted in heavy rare earth and high field strength elements. Their zircon εHf(t) values are mainly positive (+2.49 to +11.64) and yield two-stage Hf model ages of 1023–445 Ma. The geochemical and isotopic data indicate they might have been derived from the partial melting of medium- to high-K basaltic crust material during the Mesoproterozoic to Phanerozoic. They underwent fractional crystallization in the magma evolution process, and K-feldspar and plagioclase were the major crystallization phases. Combined with the temporal–spatial migration of the Mesozoic magmatic events in the whole northeastern China, we propose that the generation of Early Cretaceous highly differentiated I-type granites in the central Great Xing’an Range was associated with the delamination effect caused by the roll-back of the Paleo-Pacific plate.

Text: Methods. Figure S1: Diagrams showing chondrite-normalized REEs patterns for zircons from the high-Mg igneous associations in the Qinghe region. Figure S2: Diagrams showing variation of selected elements vs. LOI to check for element mobility during post-magmatic alteration. Figure S3: (A) SiO2 vs. Th/La and (B) MgO vs. Nb/La diagrams of the high-Mg igneous rocks in the Qinghe region. Figure S4: (A) MgO vs. CaO; (B) MgO vs. Cr; (C) MgO vs. Ni; (D) MgO vs. TiO2; (E) Sr vs. Ba; and (F) TiO2 versus V diagrams of the high-Mg igneous rocks in the Qinghe region. Mineral abbreviations: Ol—olivine; Hbl—hornblende; Cpx—clinopyroxene; Pl—plagioclase; Kf—potassium feldspar; Bi—biotite. Figure S5: Diagrams of (A) Nb/Yb vs. Th/Yb; (B) Th/Yb vs. La/Yb of the high-Mg igneous rocks in the Qinghe region. Tables S1–S5.

We performed zircon U–Pb age dating and geochemical analyses of late Mesozoic felsic volcanic rocks in the Hailar Basin, NE China, with the aim of eclucidating their emplacement ages, origin and geodynamic significance. The volcanic rocks consist of dacites, rhyolites and rhyolitic tuffs. Laser ablation–inductively coupled plasma–mass spectrometry zircon U–Pb dating results suggest that the rocks were erupted during the Late Jurassic–Early Cretaceous (161–117 Ma). They belong to the high-K calc-alkaline series and can be divided into two groups. Group I rocks are metaluminous to weakly peraluminous, contain low concentrations of heavy rare earth elements (HREEs) and high field strength elements (HFSEs), and have low zircon saturation temperatures (average 786 °C), all of which indicate an I-type affinity. In contrast, Group II rocks have higher HREE and HFSE concentrations and zircon saturation temperatures (average 918 °C), suggesting an A-type affinity. All the felsic volcanic rocks have positive εHf(t) values of 1.43–12.32 with two-stage model ages of 1110–401 Ma. Our data indicate that the I-type felsic volcanic rocks formed from magmas generated by partial melting of a dominantly juvenile mica-bearing K-rich basaltic lower crust, whereas the A-type felsic volcanic rocks originated from the partial melting of a dry mafic–intermediate middle–lower crust that was dehydrated but not melt depleted. Based on the present results and previous research, we propose that the Late Jurassic I- and A-type felsic volcanic rocks in the Hailar Basin were formed in a post-collisional environment related to break-off of the subducted oceanic slab of the Mongol–Okhotsk Ocean and the subsequent gravitational collapse of the orogenically-thickened crust after closure of the ocean. In contrast, the Early Cretaceous I- and A-type felsic volcanic rocks were erupted in an extensional setting related to rollback of the subducted Paleo-Pacific Plate.

This study presents new geochronological, whole-rock geochemical, and zircon Hf isotopic evidence for the age, petrogenesis, and source of Mesozoic granitic rocks of the Xing’an Block, Northeast China. This evidence reveals the Late Mesozoic tectonic evolution of the eastern section of the Central Asian Orogenic Belt. Laser-ablation inductively coupled plasma – mass spectrometryzircon U–Pb age data indicate that the syenogranite, monzogranite, and alkali feldspar granite units, as well as their associated diorite microgranular enclaves, were emplaced between 150–142 Ma, providing evidence of Late Jurassic to Early Cretaceous magmatic events within the Xing’an Block. The granites contain high concentrations of SiO2 (65.24%–75.73 wt.%) and K2O (3.94%–5.30 wt.%), low concentrations of MgO (0.10%–1.30 wt.%), and A/CNK values of 0.92–1.06. In addition, Hf isotopic analysis of zircons from the 150–142 Ma granites yields εHf(t) values of +4.54 to +12.16 and two-stage Hf model aged from 906 to 423 Ma, indicating that they formed from magmas generated by partial melting of a juvenile Neoproterozoic–Phanerozoic accreted crustal source. The basic magma source for the diorite microgranular enclaves most likely formed from partial melting of a depleted mantle that had been metasomatized by subduction-related fluids. Combining these new geochemical data with the geology of this region, Late Jurassic to Early Cretaceous magmatism in the Xing’an Block most likely occurred in an extensional environment associated with closure of the Mongol–Okhotsk Ocean.

We present zircon U–Pb ages, major and trace element analyses, and zircon Hf isotope data on the Late Cretaceous–Paleocene granitoids at the southern end of the Sikhote-Alin Orogenic Belt of the Russian Far East. These data are used to discuss the petrogenesis of the granitoids in the context of the paleo-Pacific subduction beneath the eastern Eurasia. Zircons from four granitoid samples give emplacement ages of ~ 56, ~ 83, ~ 91, and ~ 92 Ma. These granitoids with high SiO2 (73.43–76.76 wt%) are metaluminous to weakly peraluminous (A/CNK = 0.97–1.03) and belong to the high-K calc-alkaline series (K2O = 3.75–4.95 wt%). They are all enriched in light rare earth elements (LREEs) and large ion lithophile elements (LILEs), and relatively depleted in high field strength elements (HFSEs) with striking depletion also in Ba, Sr, P and Eu. They are petrographically and geochemically consistent with being of I-type granitoids. The zircons have εHf (t) values (− 0.8 to + 7.6) higher than whole-rock εHf (t) values predicted from whole-rock εNd (t) (− 4.1 to + 0.5) in the literature. All these observations suggest that primary magmas parental to these granitoids were likely to have derived from partial melting of a juvenile lower crust accompanied by assimilation with ancient mature crust during magma ascent and evolution. A recent study illustrates that the collision of an exotic terrane carried by the paleo-Pacific plate with the continental China at ~ 100 Ma accreted the basement of the Chinese continental shelf (beneath East and South China Seas), and resulted in a new plate boundary of transform nature between the NNW moving paleo-Pacific plate and the eastern margin of the shelf. Our new data and analysis of existing data support this hypothesis, but we hypothesize that this transform becomes transpressional in its northern segment with oblique subduction of the paleo-Pacific plate beneath northeastern Asia as manifested by the Late Cretaceous-Paleocene granitoids in the Russian Far East-NE China (97–56 Ma) and South Korea-SW Japan (96–71 Ma). These tectonic and magmatic events took place prior to the opening of the Huanghai, Bohai and Japan seas, which are of rift-origin from continental China much later. Our study emphasizes the necessity and significance of plate tectonics reconstruction in the greater northwestern Pacific region since the Cretaceous.

Northeast (NE) China is characterized by immense volumes of granitic rocks, exposed over an area of ∼200,000 km 2 . Although the precise geochronological framework was not clear, it was considered that most of them were emplaced during the Paleozoic, when numerous tectonic blocks amalgamated. Over the past decade, we have selected 370 samples for zircon U–Pb dating in order to constrain the spatial and temporal distribution of granitoids in the area. These data, combined with 63 ages obtained by other researchers, indicate that Paleozoic granitoids are not as widely distributed in the area as previously thought. In the eastern part of the area, granitoids in the Zhangguangcai Range were mostly emplaced during the Jurassic (150–190 Ma) with a small amount in the Paleozoic, whereas granitoids in the Nadanhada Terrane, the easternmost part of NE China, have an emplacement age of ∼115 Ma. In the west, granitoids exposed in the Great Xing’an Range were mainly formed during the Early Cretaceous (120–135 Ma) with some in the Paleozoic, and those in the Erguna Massif, the westernmost part of NE China, were emplaced during the Jurassic (160–190 Ma). Based on the temporal–spatial distribution of these granitic rocks, it is suggested that the Paleozoic granitoids were formed during various stages from oceanic subduction to block amalgamation in the Central Asian Orogenic Belt (CAOB). It is proposed that the Jurassic granitoids in the Zhangguangcai Range were probably related to Paleo-Pacific plate subduction west of the Jiamusi Massif (block). This subduction resulted in regional lithospheric thickening, and subsequent delamination of the thickened lithosphere due to its gravity instability in the Early Cretaceous. Unlike other areas in the Central Asian Orogenic Belt, NE China was significantly affected by subduction of the Paleo-Pacific ocean, and can be considered as one of the most important areas of the eastern Asian active continental margin during the Mesozoic.

NE China is the easternmost part of the Central Asian Orogenic Belt (CAOB). The area is distinguished by widespread occurrence of Phanerozoic granitic rocks. In the companion paper (Part I), we established the Jurassic ages (184–137 Ma) for three granitic plutons: Xinhuatun, Lamashan and Yiershi. We also used geochemical data to argue that these rocks are highly fractionated I-type granites. In this paper, we present Sr–Nd–O isotope data of the three plutons and 32 additional samples to delineate the nature of their source, to determine the proportion of mantle to crustal components in the generation of the voluminous granitoids and to discuss crustal growth in the Phanerozoic. Despite their difference in emplacement age, Sr–Nd isotopic analyses reveal that these Jurassic granites have common isotopic characteristics. They all have low initial 87 Sr/ 86 Sr ratios (0.7045F0.0015), positive eNd(T) values (+1.3 to +2.8), and young Sm–Nd model ages (720–840 Ma). These characteristics are indicative of juvenile nature for these granites. Other Late Paleozoic to Mesozoic granites in this region also show the same features. Sr–Nd and oxygen isotopic data suggest that the magmatic evolution of the granites can be explained in terms of two-stage processes: (1) formation of parental magmas by melting of a relatively juvenile crust, which is probably a mixed lithology formed by pre-existing lower crust intruded or underplated by mantle-derived basaltic magma, and (2) extensive magmatic differentiation of the parental magmas in a slow cooling environment. The widespread distribution of juvenile granitoids in NE China indicates a massive transfer of mantle material to the crust in a post-orogenic tectonic setting. Several recent studies have documented that juvenile granitoids of Paleozoic to Mesozoic ages are ubiquitous in the Central Asian Orogenic Belt, hence suggesting a significant growth of the continental crust in the Phanerozoic. D 2003 Elsevier Science B.V. All rights reserved.

Northeastern (NE) China is the easternmost part of the Central Asian Orogenic Belt (CAOB), which is celebrated for its accretionary tectonics and the world's most important juvenile crust production in the Phanerozoic era. Abundant granitoids occur in the Great Xing'an, Lesser Xing'an and Zhangguangcai Ranges in NE China. This paper presents partial results of a series of studies on the granitoids from this region, aiming to understand their role in the building of new continental crust in eastern Asia. Three composite granite plutons (Xinhuatun, Lamashan and Yiershi) were chosen for geochemical and isotopic study in order to determine their emplacement ages and petrogenesis. Petrographically, they range from granodiorite (minor), monzogranite, syenogranite to alkali-feldspar granite. Quartz and perthitic feldspar are principal phases, accompanied by minor amounts of plagioclase, biotite (