The late Mesozoic magmatic record within the Erguna Block is critical to evaluate the tectonic history and geodynamic evolution of the Great Xing’an Range, NE China. Here, we provide geochronological and geochemical data on Late Jurassic–Early Cretaceous plutonic-volcanic rocks in the northern Erguna Block and discuss their origin within a regional tectonic framework. Late Mesozoic magmatism in the Erguna Block can be divided into two major periods: Late Jurassic (162–150 Ma) and Early Cretaceous (140–125 Ma). Late Jurassic quartz monzonite and dacite show adakite characteristics such as high Al₂O₃, high Sr, and steeply fractionated REE patterns. Contemporary granitoids and rhyolites are also characterized by strong enrichment of light rare earth elements (LREE) and significant depletion in heavy rare earth elements (HREE), but with more pronounced negative Eu anomalies. Early Cretaceous trachytes and monzoporphyries exhibit moderate LREE enrichment and relatively flat HREE distributions. Coeval granites and rhyolites have transitional signatures between A-type and fractionated I-type felsic rocks. Both Late Jurassic and Early Cretaceous rocks have distinctive negative Nb, Ta, and Ti anomalies, and positive zircon ε_Hf(t) values, suggesting that these magmas were derived from partial melting of Meso-Neoproterozoic accreted lower crust, although melting occurred at a variety of crustal levels. The transition from adakite to non-adakite magmatism reflects continued crustal thinning from Late Jurassic to Early Cretaceous. Our data, together with recently reported isotopic data for plutonic and volcanic rocks, as well as geochemical data, in NE China, suggest that Late Jurassic–Early Cretaceous magmatism in the Erguna Block was possibly induced by post-collisional extension after closure of the Mongol-Okhotsk Ocean.

The Tayuan plutons located at the boundary of the Erguna and Xing’an blocks expose a coexisting mafic–felsic association that is made of monzogranite and gabbro-monzodiorite as well as subordinate quartz monzonite. LA–ICP–MS U–Pb zircon dating revealed a synchronous emplacement of the monzogranite (314–317 Ma), gabbro (308–315 Ma), and quartz monzonite (310 ± 3 Ma). The majority of these intrusions are characterized by an enrichment in light rare earth elements relative to heavy rare earth elements and a depletion of high strength field elements (e.g. Nb, Ta, Ti). Zircons from the gabbro and monzogranite have ε_Hf(t) values of 1.1–9.6 and −3.0–3.3, respectively. Geochemical data show that the gabbro-monzodiorite may have been generated by the melting of a fluid-metasomatized lithospheric mantle, while the monzogranite may have been formed by a partial melting of the Mesoproterozoic crust. The quartz monzonite has similar whole-rock geochemical and Hf isotopic compositions to those of the gabbros and could have been produced from the same mantle source as that from which the gabbros were extracted. The Tayuan plutonic rocks have high contents of K₂O and total alkalis and show a northwestward polarity like that of the continental margin plutonic rocks along the Hegenshan–Heihe suture zone. Combined with data from published studies, our data indicate that the Tayuan intrusive rocks were generated by the northwestward subduction of the Hegenshan–Heihe Oceanic plate.

The late Mesozoic magmatic record within the Erguna Block is critical to evaluate the tectonic history and geodynamic evolution of the Great Xing’an Range, NE China. Here, we provide geochronological and geochemical data on Late Jurassic–Early Cretaceous plutonic-volcanic rocks in the northern Erguna Block and discuss their origin within a regional tectonic framework. Late Mesozoic magmatism in the Erguna Block can be divided into two major periods: Late Jurassic (162–150 Ma) and Early Cretaceous (140–125 Ma). Late Jurassic quartz monzonite and dacite show adakite characteristics such as high Al₂O₃, high Sr, and steeply fractionated REE patterns. Contemporary granitoids and rhyolites are also characterized by strong enrichment of light rare earth elements (LREE) and significant depletion in heavy rare earth elements (HREE), but with more pronounced negative Eu anomalies. Early Cretaceous trachytes and monzoporphyries exhibit moderate LREE enrichment and relatively flat HREE distributions. Coeval granites and rhyolites have transitional signatures between A-type and fractionated I-type felsic rocks. Both Late Jurassic and Early Cretaceous rocks have distinctive negative Nb, Ta, and Ti anomalies, and positive zircon ε_Hf(t) values, suggesting that these magmas were derived from partial melting of Meso-Neoproterozoic accreted lower crust, although melting occurred at a variety of crustal levels. The transition from adakite to non-adakite magmatism reflects continued crustal thinning from Late Jurassic to Early Cretaceous. Our data, together with recently reported isotopic data for plutonic and volcanic rocks, as well as geochemical data, in NE China, suggest that Late Jurassic–Early Cretaceous magmatism in the Erguna Block was possibly induced by post-collisional extension after closure of the Mongol-Okhotsk Ocean.

The Tayuan plutons located at the boundary of the Erguna and Xing’an blocks expose a coexisting mafic–felsic association that is made of monzogranite and gabbro-monzodiorite as well as subordinate quartz monzonite. LA–ICP–MS U–Pb zircon dating revealed a synchronous emplacement of the monzogranite (314–317 Ma), gabbro (308–315 Ma), and quartz monzonite (310 ± 3 Ma). The majority of these intrusions are characterized by an enrichment in light rare earth elements relative to heavy rare earth elements and a depletion of high strength field elements (e.g. Nb, Ta, Ti). Zircons from the gabbro and monzogranite have ε_Hf(t) values of 1.1–9.6 and −3.0–3.3, respectively. Geochemical data show that the gabbro-monzodiorite may have been generated by the melting of a fluid-metasomatized lithospheric mantle, while the monzogranite may have been formed by a partial melting of the Mesoproterozoic crust. The quartz monzonite has similar whole-rock geochemical and Hf isotopic compositions to those of the gabbros and could have been produced from the same mantle source as that from which the gabbros were extracted. The Tayuan plutonic rocks have high contents of K₂O and total alkalis and show a northwestward polarity like that of the continental margin plutonic rocks along the Hegenshan–Heihe suture zone. Combined with data from published studies, our data indicate that the Tayuan intrusive rocks were generated by the northwestward subduction of the Hegenshan–Heihe Oceanic plate.

The Tayuan plutons located at the boundary of the Erguna and Xing’an blocks expose a coexisting mafic–felsic association that is made of monzogranite and gabbro-monzodiorite as well as subordinate quartz monzonite. LA–ICP–MS U–Pb zircon dating revealed a synchronous emplacement of the monzogranite (314–317 Ma), gabbro (308–315 Ma), and quartz monzonite (310 ± 3 Ma). The majority of these intrusions are characterized by an enrichment in light rare earth elements relative to heavy rare earth elements and a depletion of high strength field elements (e.g. Nb, Ta, Ti). Zircons from the gabbro and monzogranite have ε_Hf(t) values of 1.1–9.6 and −3.0–3.3, respectively. Geochemical data show that the gabbro-monzodiorite may have been generated by the melting of a fluid-metasomatized lithospheric mantle, while the monzogranite may have been formed by a partial melting of the Mesoproterozoic crust. The quartz monzonite has similar whole-rock geochemical and Hf isotopic compositions to those of the gabbros and could have been produced from the same mantle source as that from which the gabbros were extracted. The Tayuan plutonic rocks have high contents of K₂O and total alkalis and show a northwestward polarity like that of the continental margin plutonic rocks along the Hegenshan–Heihe suture zone. Combined with data from published studies, our data indicate that the Tayuan intrusive rocks were generated by the northwestward subduction of the Hegenshan–Heihe Oceanic plate.

This study reports new zircon U–Pb ages, Lu–Hf isotope data, and oxygen isotope data for Mesozoic Mo-bearing granitoids in the eastern Xing–Meng Orogenic Belt (XMOB) of Northeast China, within the eastern Central Asian Orogenic Belt. Combining these new laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb ages with the results of previous research indicates that two stages of Mo-bearing granitoid magmatism occurred in the eastern XMOB, during the Early–Middle Jurassic (200–165 Ma) and the Early Cretaceous (ca. 111 Ma). The eastern XMOB also contains Mo-bearing granitoids with variable δ¹⁸O compositions that record variations in source oxygen isotopic compositions. Combining δ¹⁸O data with zircon U–Pb and Hf isotopic data provides evidence of the origin of these granitoids. Three types of zircon have been identified within these granitoids. Type 1 zircons formed during the Mesozoic and having high δ¹⁸O values (5.71–7.05‰) that are consistent with the compositions of magmatic zircons from the Luming, Jiapigou, and Kanchuangou areas. These zircons suggest that the Mo-bearing granitoids were derived from a source containing supracrustal materials. The type 2 zircons have extremely low and heterogeneous δ¹⁸O values (4.64–4.89‰) that are consistent with the compositions of magmatic zircons from the Jidetun and Fuanpu areas. These magmas were generated by the remelting of juvenile crustal material that was previously significantly modified by interaction with fluids. Type 3 zircons generally have mantle-like δ¹⁸O values (5.42–5.57‰), with several zircons yielding higher δ¹⁸O values, suggesting that these intrusions formed from mantle-derived magmas that assimilated and were metasomatized by crustal material. Combining these geochemical data with the geology of this region indicates that the Mo-bearing granitoids were generated as a result of subduction of the Palaeo-Pacific Plate beneath the Eurasian continent.

This paper presents major element, trace element, and new zircon Hf isotopic data for the Early Mesozoic intrusive rocks in the south Hunchun, Yanbian area, Northeast China. These data are used to constrain the petrogenesis of these intrusive rocks and their implications for the Phanerozoic continental growth of the Central Asian Orogenic Belt (CAOB). Combining geology, geochronology, and whole-rock geochemistry, we identify three distinct episodes of magmatism as Early–Middle Triassic (249–237 Ma), Late Triassic (224–206 Ma), and Early Jurassic (200–187 Ma). The Early–Middle Triassic (249–237 Ma) adakitic tonalite and granodiorite were produced by the partial melting of subducted oceanic slabs, and the melts were contaminated by mantle peridotite during their ascent, whereas the coeval non-adakitic diorite and monzogranite were most likely derived from partial melting of crustal material. The remarkably high zircon Hf isotopic signature (ε_Hf(t) = + 9.4 – +18.9), the enrichment in large-ion lithophile element and light rare earth elements, and the depletion in high field strength element suggest that these 224 Ma gabbros were derived from the partial melting of depleted mantle modified by subduction-related fluids. The 212 Ma monzogranite was most likely derived from juvenile material mixed with old crustal material as evidenced by their high SiO₂, low MgO, and low Cr concentrations and variable ε_Hf(t) values (–4.6 to +10.0). Except for the 197 Ma tonalites with affinity to the high silica adakites, the overall geochemical evolution of Early Jurassic (200–187 Ma) rocks was consistent with fractional crystallization from quartz diorite, granodiorite, and monzogranite to syenogranite. Both the Early Jurassic syn-subduction lateral continental growth by accretion of arc complexes and the Late Triassic post-collisional vertical continental growth by accretion of mantle-derived material played an important role in the Phanerozoic continental growth of the CAOB.

This paper presents major element, trace element, and new zircon Hf isotopic data for the Early Mesozoic intrusive rocks in the south Hunchun, Yanbian area, Northeast China. These data are used to constrain the petrogenesis of these intrusive rocks and their implications for the Phanerozoic continental growth of the Central Asian Orogenic Belt (CAOB). Combining geology, geochronology, and whole-rock geochemistry, we identify three distinct episodes of magmatism as Early–Middle Triassic (249–237 Ma), Late Triassic (224–206 Ma), and Early Jurassic (200–187 Ma). The Early–Middle Triassic (249–237 Ma) adakitic tonalite and granodiorite were produced by the partial melting of subducted oceanic slabs, and the melts were contaminated by mantle peridotite during their ascent, whereas the coeval non-adakitic diorite and monzogranite were most likely derived from partial melting of crustal material. The remarkably high zircon Hf isotopic signature (ε_Hf(t) = + 9.4 – +18.9), the enrichment in large-ion lithophile element and light rare earth elements, and the depletion in high field strength element suggest that these 224 Ma gabbros were derived from the partial melting of depleted mantle modified by subduction-related fluids. The 212 Ma monzogranite was most likely derived from juvenile material mixed with old crustal material as evidenced by their high SiO₂, low MgO, and low Cr concentrations and variable ε_Hf(t) values (–4.6 to +10.0). Except for the 197 Ma tonalites with affinity to the high silica adakites, the overall geochemical evolution of Early Jurassic (200–187 Ma) rocks was consistent with fractional crystallization from quartz diorite, granodiorite, and monzogranite to syenogranite. Both the Early Jurassic syn-subduction lateral continental growth by accretion of arc complexes and the Late Triassic post-collisional vertical continental growth by accretion of mantle-derived material played an important role in the Phanerozoic continental growth of the CAOB.

This study reports new zircon U–Pb ages, Lu–Hf isotope data, and oxygen isotope data for Mesozoic Mo-bearing granitoids in the eastern Xing–Meng Orogenic Belt (XMOB) of Northeast China, within the eastern Central Asian Orogenic Belt. Combining these new laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) zircon U–Pb ages with the results of previous research indicates that two stages of Mo-bearing granitoid magmatism occurred in the eastern XMOB, during the Early–Middle Jurassic (200–165 Ma) and the Early Cretaceous (ca. 111 Ma). The eastern XMOB also contains Mo-bearing granitoids with variable δ¹⁸O compositions that record variations in source oxygen isotopic compositions. Combining δ¹⁸O data with zircon U–Pb and Hf isotopic data provides evidence of the origin of these granitoids. Three types of zircon have been identified within these granitoids. Type 1 zircons formed during the Mesozoic and having high δ¹⁸O values (5.71–7.05‰) that are consistent with the compositions of magmatic zircons from the Luming, Jiapigou, and Kanchuangou areas. These zircons suggest that the Mo-bearing granitoids were derived from a source containing supracrustal materials. The type 2 zircons have extremely low and heterogeneous δ¹⁸O values (4.64–4.89‰) that are consistent with the compositions of magmatic zircons from the Jidetun and Fuanpu areas. These magmas were generated by the remelting of juvenile crustal material that was previously significantly modified by interaction with fluids. Type 3 zircons generally have mantle-like δ¹⁸O values (5.42–5.57‰), with several zircons yielding higher δ¹⁸O values, suggesting that these intrusions formed from mantle-derived magmas that assimilated and were metasomatized by crustal material. Combining these geochemical data with the geology of this region indicates that the Mo-bearing granitoids were generated as a result of subduction of the Palaeo-Pacific Plate beneath the Eurasian continent.

Late Triassic–Early Jurassic intrusions of the Erguna Block, Northeast China, are located along the southern margin of the Mongol–Okhotsk orogenic belt. They comprise granodiorite, monzogranite, syenogranite, and lesser gabbro–diorite, of adakitic and calc­alkaline affinity. The adakite-like and calc­alkaline granites share similar light rare earth elements (LREE) characteristics; however, their heavy rare earth elements (HREE) trends differ from one another. The relative abundances of HREE in the calc­alkaline granites are relatively consistent and are similar to those of intrusive rocks formed from dehydration melting of garnet-free amphibolitic source rocks at relatively low pressures. In contrast, the adakite-like granites show more prominent HREE fractionation trends, indicating that they crystallized at higher pressures, where garnet in the source rocks was stable. At least two isotopically distinct sources were involved in the petrogenesis of the granites, but the extent to which they contributed varies between plutons. Most intrusions have incorporated an isotopically primitive component, possibly juvenile mafic crust. The other sources include a small proportion of old continental crustal material and isotopically evolved wall rocks. The gabbro–diorites have high MgO contents (>7 wt.%), a high Mg^# (>0.6), and show moderate LREE and HREE fractionation, indicating they formed from the melting of subducted metasomatized lithospheric mantle. All of the intrusions in the study area are characterized by a relative enrichment in large ion lithophile elements (LILE) and depletion in high field strength elements (HFSE), indicating they were emplaced in an Andean-type active continental margin setting related to southward subduction of the Mongol–Okhotsk oceanic plate.