The Khondalite Belt (KB) is a Paleoproterozoic collisional orogen within the North China Craton (NCC), but its pre-collisional tectonic evolution remains poorly constrained. In this study, we conducted integrated geochronological, in-situ Hf isotopic, and whole-rock geochemical analyses of the mafic–intermediate intrusions exposed in the Daqingshan area of the central KB to determine their formation ages, petrogenesis, and tectonic setting, thereby further constraining the late Paleoproterozoic tectonic evolution of the KB. Zircon U-Pb dating results show that these rocks crystallized at ∼1.97–1.96 Ga and subsequently underwent metamorphism at ∼1.94–1.92 Ga. These rocks are enriched in light rare earth elements and depleted in high field strength elements, exhibiting geochemical affinities comparable to those of continental margin arc basalts and island arc basalts. In-situ zircon Hf isotopic analyses yield positive εHf(t) values. The available data suggest that the mafic–intermediate intrusions were derived from a hybrid mantle source dominated by asthenospheric mantle and metasomatized by fluids derived from a subducted slab and experienced fractional crystallization of olivine, clinopyroxene, Fe-Ti oxides and apatite. Overall, these findings suggest that the KB was in a subduction-related tectonic setting at ∼1.97–1.96 Ga. Subsequent continent–continent collision at ∼1.95 Ga resulted in metamorphism of both the magmatic rocks and the Khondalite Series at ∼1.94–1.92 Ga.

Understanding the Early Palaeozoic evolution of the Paleo-Asian Ocean (PAO) is critical for reconstructing the accretionary processes of the Central Asian Orogenic Belt (CAOB). Here, we present a systematic study of supra-subduction zone (SSZ) ophiolites and adakites from central Inner Mongolia, North China, to elucidate the subduction dynamics of the PAO. Zircon U-Pb dating results indicate that the SSZ-type ophiolitic rocks formed at similar to 490 Ma, whereas the adakitic trondhjemites yield a crystallisation age of similar to 448 Ma. The metagabbros exhibit tholeiitic affinities and are characterised by high Mg contents, enrichment in LILEs and depletion in HFSEs, indicating a subduction-related origin. The quartz diorites, identified as newly discovered plagiogranites, display SSZ-type geochemical characteristics with high SiO2, low K2O and enriched HFSEs, suggesting that the plagiogranites in the Tulinkai ophiolite are similar to plagiogranites derived from partial melting. The adakitic trondhjemites are characterised by high SiO2, Al2O3, Sr and Sr/Y ratios, low Y and Yb contents, and positive Eu anomalies, suggesting their derivation from the partial melting of subducted basaltic oceanic crust. The zircon positive epsilon(Hf)(t) values support a derivation from juvenile crust. Integrating these findings with regional geological data, we propose that southward subduction of the PAO was already established by similar to 490 Ma along the Ondor Sum-Tulinkai belt, followed by sustained SSZ magmatism and adakitic magmatism, reflecting a long-lived subduction system along the southern CAOB during the Early Palaeozoic.

The western Yunnan is tectonically located in the southeastern margin of the Tethys tectonic domain, with intensive Cenozoic magmatism. The understanding of the genesis and dynamic background of the Cenozoic granites in this area remains controversial. We conducted zircon U-Pb geochronology, whole-rock major and trace elements, and zircon Hf isotope analyses upon the Cenozoic Changning and Yunxian monzogranites in the northern part of the Lincang granite batholith. The results show that the Changning monzogranites crystallized at similar to 46Ma. Geochemically, they belong to calc-alkaline series, and characterized by high potassium and low calcium contents with A/CNK ratios ranging from 1.07 to 1.08, and enriched in light rare earth elements and large ion lithophile elements relative to high field strength elements. The epsilon(Hf)(t) values range from -4.93 to -2.20, with the two-stage model ages from 1.43Ga to 1.26Ga, belonging to adakitic affinity. The source rocks of the monzogranites are originated from partial melting of the thickened ancient lower crust. By contrast, the Yunxian monzogranites is formed at similar to 27Ma. They belong to strongly peraluminous sereies and featured by high-K calc-alkaline with low magnesium contents, and enriched in light rare earth elements and large ion lithophile elements and depleted in high field strength elements. The epsilon(Hf)(t) values and two-stage model ages (t(DM2)) of analysized samples range from -5.97 to -2.34 and 1.99Ga to 1.26Ga respectively. The sources rocks of this pluton are of highly differentiated S-type granite characteristics, and are generated by dehydration melting of metapelitic rocks. Combined with regional geological data, we propose a two-stage model to explain the formation of these monzogranites: (1) due to the rollback of the subducted Neo-Tethys slab, the lithospheric mantle underwent convective thinning, inducing asthenosphere upwelling and partial melting of the thickened ancient lower crust and formed the Changning monzogranites; (2) subsequently, the shear heating which derived from the large-scale strike-slip shearing activities in the Cenozoic induced dehydration melting of the continental crust and generated the Yunxian monzogranites.

Archean tonalite-trondhjemite-granodiorite (TTG) suite and K-rich granitoids provide direct evidence of the generation and differentiation of the Archean continental crust. Within the North China Craton (NCC), the Anshan area serves as an exceptional natural laboratory, preserving a geological record spanning from 3.8 to 2.5 Ga. Here, we conducted comprehensive geochemical, geochronological, and zircon Hf-O isotopic analyses for the Paleoarchean-Mesoarchean granitoids from the Anshan region. Zircon U-Pb dating suggest that these granitoids formed during 3.3-3.1 Ga. The ca. 3.3 Ga monzogranitic gneisses exhibit high SiO2 and K2O, low Mg# values, negative Eu anomalies, unradiogenic Hf isotopes (i.e., epsilon Hf(t) values = -5.16-+0.08, TDM and "mantle-like" 518O values (up to + 5.64 %o). Geochemical features divide them into two distinct groups, both are recycling products of pre-existing Eoarchean TTGs. Group 1 and Group 2 originated from 10 %-20 % and 20 %-30 % partial melting of pre-existing Eoarchean TTGs at depths of 1.25-1.75 GPa and 0.5-0.75 GPa, respectively. The ca. 3.3 Ga trondhjemite gneisses show high SiO2, low Mg# values, low Sr/Y and (La/Yb)N ratios. Their epsilon Hf(t) values range from + 0.91 to + 1.10, with TDM 2 ages of 3682-3665 Ma. In contrast, the ca. 3.3 Ga monzonitic gneisses have lower SiO2 contents, higher Al2O3, total alkali (Na2O + K2O), and Sr/Y and (La/Yb)N ratios. Their epsilon Hf(t) values range from -2.69 to + 0.50, with TDM 2 ages of 4040-3750 Ma. The ca. 3.1 Ga trondhjemite gneisses display higher Sr/Y and (La/Yb)N ratios, enriched LREEs and depleted HREEs. Magmatic zircons yield 518O values of 3.87-6.52 %o and epsilon Hf(t) values of -2.39 to + 0.95, with TDM 2 ages of 3881-3550 Ma. The geochemical and Hf-O isotope characteristics suggest that both the 3.3-3.1 Ga trondhjemite gneisses and the ca. 3.3 Ga monzonitic gneisses originated from partial melting of mafic rocks at variable depths. During 3.3-3.1 Ga, the NCC experienced intensive crustal growth and rework/recycling. Two magmatic events (ca. 3.3 Ga and ca. 3.1 Ga) and subsequent tectono-thermal events were induced by multi-stage magmatic underplating of mantle upwelling within a plume-related tectonic setting.

Zircon U-Pb geochronology, geochemistry and Hf isotope analysis of supracrustal rocks in the Anshan-Benxi area in the northeastern part of the North China Craton can help constrain their petrogenesis and tectonic background, providing evidence for a further investigation of the late Neoarchaean tectonic environment in the Anshan-Benxi area. The primary rock types observed among the supracrustal rocks in the Anshan-Benxi area comprise amphibolite, metamorphic rhyolite, metamorphic sandstone, chlorite schist, actinolite schist, among others. SHRIMP zircon U-Pb dating indicates that magmatic zircons from the amphibolite (GCN-1) formed at 2553 +/- 18Ma. Similarly, LA-ICP-MS zircon U-Pb dating reveals that magmatic zircons from the metamorphic rhyolite (G2304-1) were formed at 2457 +/- 35Ma. The peak age of the metamorphic sandstone is determined to be approximately 2500Ma, suggesting that the supracrustal rocks in the Anshan-Benxi area originated in the late Neoarchaean. The protoliths of sericite quartz schist and metamorphic rhyolite are identified as rhyolitic volcanic rocks, displaying a right-leaning distribution pattern of rare earth elements (REEs). On the other hand, actinolite schist, chlorite schist and amphibolite are classified as basaltic volcanic rocks, exhibiting a flat REE pattern with a weak negative Eu anomaly. The epsilon Hf(t) value of metamorphic rhyolite ranges between -1.19 and -1.47, with a two- stage depleted mantle model age of tDM2(Ma) = 2922-3132 Ma. The protolith magma of sericite quartz schist and metamorphic rhyolite originates from partial melting of 3.0Ga basaltic crust, while the source of actinolite schist, chlorite schist and amphibolite are mainly derived from the mantle. In summary, the findings suggest that plate already existed in the late Neoarchaean or earlier, with magmatism in the Anshan-Benxi area likely occurring within an arc tectonic environment linked to plate subduction.

The application of zircon U-Pb geochronology, geochemistry, and Hf isotope analysis to the granitoid complex in the Laoling area of southern Jilin Province (SJP) in the northeastern part of the North China Craton can provide valuable insights into its petrogenesis and tectonic setting. The predominant rock types found in SJP granitoid complex encompass monzonitic granite, tonalite, and various other varieties. The zircon U-Pb dating results indicate that the monzonitic granite (N20HT-1-1) crystallized at 2499 +/- 4.2 Ma, the tonalite (N20HT-2-1) at 2722 +/- 30 Ma, and the mylonitized tonalite (PH01-14-2) at 2505 +/- 15 Ma, the monzonitic granite (DA19-3) at 2563 +/- 16 Ma. Through the analysis of Hf isotopes, two-stage depleted mantle model ages, and elemental geochemistry, the inference can be made that tonalite enriched with the residual magmatic zircon are originally formed by the partial melting of similar to 3.4 Ga basaltic crust. Besides, the magmas of the monzonitic granite and mylonitized tonalite were sourced from the partial melting of potassium-rich basaltic rocks and a small amount of metasedimentary units and TTG suite rocks within the lower crust of the Meso- to Neoarchaean (3.1-2.7 Ga) continental framework. Based on this study and previous findings, it can be concluded that there are primarily three phases of magmatic activity in SJP: During the Mid Neoarchaean period (similar to 2.7 Ga), the basaltic crust underwent partial melting due to the tectonic influence of a mantle plume, resulting in the formation and emplacement of tonalite-trondhjemitic magma. In the Late Neoarchaean period (similar to 2.6 Ga), a transition occurred from mantle plume to plate subduction. It was during this time that monzonitic granite began to develop, suggesting the initiation of the plate tectonic system. At the End Neoarchaean period (similar to 2.5 Ga), a significant amount of potassium-rich granite erupted as a result of plate subduction processes. Furthermore, it is worth noting that the tectonic setting for monzonitic granite in SJP indicates a post-orogenic extensional environment, implying that felsic magmatism during this phase is associated with dynamic processes related to arc-continent collision caused by plate subduction followed by subsequent post-collision extension.

ABSTRACTUnderstanding the Late Palaeozoic accretionary processes responsible for the formation of the eastern Central Asian Orogenic Belt (CAOB) is crucial for unravelling continental growth mechanisms in this region. This study systematically investigates newly identified volcanic rocks in the northern margin of the North China Block (NCB) and Bainaimiao Arc Belt (BAB), aiming to elucidate their petrogenesis, tectonic setting and implications for the evolution of the Paleo‐Asian Ocean (PAO). Zircon U–Pb dating reveals that these volcanic rocks were emplaced between 278 and 260 Ma. The intermediate‐mafic volcanic rocks exhibit typical subduction‐related geochemical signatures, including low TiO₂ contents, enrichment in Rb, Ba, U, K, Pb and Sr., and depletion in Nb and Ta, reflecting derivation from a subduction‐modified lithospheric mantle. The acidic volcanic rocks, characterised by high SiO₂ and Al₂O₃ contents and pronounced negative Eu anomalies, are interpreted as products of partial melting of the lower continental crust with fractional crystallisation. The εHf(t) values range from highly positive in the BAB region to lower values in the NCB, highlighting the incorporation of juvenile crustal material in the north and ancient crustal components in the south. Geochemical and isotopic evidence suggests that the volcanic rocks formed in an Andean‐type continental arc during the southward subduction of the PAO beneath the northern margin of the NCB. After 260 Ma, the tectonic setting transitioned to an extensional environment, as reflected in the geochemistry of younger intraplate granites. These findings suggest that the PAO continued subduction until the Late Permian, followed by slab break‐off and post‐collisional extension. The crustal thickening (40–66 km) and widespread magmatism indicate significant juvenile crustal growth during the Middle to Late Permian. Combined with regional tectonic data, this study provides critical insights into the geodynamic processes driving crustal evolution in the eastern CAOB.

A previously unidentified overthrust system has recently been discovered in the Ondor Sum area at the boundary between the Solonker - Xar Moron Suture Zone (SXSZ) and the Early to Mid - Paleozoic Subduction - accretion Belt to the south. The overthrusting occurred during the middle Permian and was overprinted by late Permian to Middle Triassic dextral shearing. The overthrusting (D1) was characterized by the development of WSW - ENE-trending folds and reverse faults, implying NNW - SSE shortening. The later deformation (D2) involved WSW - ENE dextral strike-slip shearing with a minor reverse component, as indicated by slightly plunging striae on slickensides. A comparison of geochronological and structural data for ophiolites in the SXSZ suggests that the overthrust system formed in response to the closure of the Solonker Ocean and the collision along the SXSZ. The earlier NNW - SSE shortening and later WSW - ENE dextral shearing indicate that a tectonic transformation took place along the SXSZ from the middle Permian to the Late Triassic. Dextral and sinistral strike-slip faults are, respectively, distributed to the south and northwest of the Songliao - Xilinhot Block to the north of the SXSZ, implying eastward extrusion of the Songliao - Xilinhot Block after the closure of Solonker Ocean. The tectonic transformation and extrusion might have been a part of the intracontinental tectonic transformation of the eastern segment of the southern Central Asian Orogenic Belt.

The geodynamic regime that governed the crustal evolution of Earth during the early Archean remains intensely debated. The North China Craton (NCC) preserves a geological history spanning 3.8-2.5 Ga, particularly in the Anshan area, making it an ideal natural laboratory for probing the formation and evolution of the NCC and its associated geodynamic regime. Here, we document new geochronology, geochemistry, and zircon Hf-O isotope data from newly discovered Paleoarchean meta -mafic rocks in the Anshan area. Based on their whole -rock geochemistry, these unit can be divided into tholeiitic and komatiitic series. Of which, the komatiitic rocks are characteristic by high MgO contents (up to 20.6 wt%). Zircon U-Pb dating shows that all meta -mafic rocks formed contemporaneously, with crystallization ages of ca. 3.3 Ga. Most of the studied meta -mafic rocks display radiogenic zircon Hf isotopes, with T DM1 ages ranging from 3592 to 3346 Ma and epsilon Hf ( t ) values from -1.94 to + 3.49. They also exhibit mantle -like zircon delta 18 O values (+4.92 %o to + 5.98 %o). These zircon Hf-O isotope data indicate that the protoliths of the ca. 3.3 Ga meta -mafic rocks originated from the partial melting of a depleted mantle without significant crustal contamination. Furthermore, the parental magmas of the komatiitic rocks and some of tholeiitic rocks were generated from 20 % and 5-10 % partial melting of spinel-lherzolite, respectively, whereas other tholeiitic rocks were the result of a low degree (1-5 %) of partial melting of spinel-garnet lherzolite. The ca. 3.3 Ga tholeiitic-komatiitic rocks were most likely formed in an intraplate rifting setting, associated with a mantle plume.

Modern analogues of Archaean charnockite are important because they facilitate investigations into processes of early crustal formation and tectonic transition. Herein, we present the results of the petrography, geochemistry, and isotope geochronology of Late Neoarchean charnockites in the Daqingshan terrane at the northern margin of the North China Craton. The sources, petrogenesis, and tectonic implications of the samples obtained are determined based on their geochemical characteristics. Charnockites mainly exhibit magnesian and calc-alkaline characteristics; furthermore, they contain high amounts of light rare-earth elements, with slightly positive Eu anomalies. Analysis of zircon U-Pb dating using a sensitive high-resolution ion microprobe reveals that Hademengou-Xiwulanbulang (HDMG-XWLBL) charnockites were emplaced during the (i) Late Neoarchean (ca. 2500 Ma), with zircon & epsilon;Hf(t) values ranging from 1.57 to 7.81; (ii) single-stage model ages (T-DM1) from 2529 to 2637 Ma; and (iii) two-stage model ages (T-DM2) from 2710 to 2820 Ma. A comparative study has performed on the petrography, geochemistry, and geochronology of charnockite and granulite shown that the parent magma of the charnockites is the product of the partial melting of granulite. Combining our results with geological data pertaining to the Archaean structural evolution of the Daqingshan terrane, we speculate that the Late Neoarchean HDMG-XWLBL charnockite was formed during a subduction-related thermo-tectonic event in the northern margin of the North China Craton.

•Cambrian Mantou Formation of the NCC has two cluster ages with Gondwana affinity.•East Gondwana and Cambrian palaeo-highland of the NCC were major provenances.•The NCC was close to the northeastern Gondwana during the early Paleozoic.

The temporal and spatial extents of the Palaeo–Pacific and Mongol–Okhotsk tectonic systems, which together dominated the Mesozoic tectonics of NE China, still remain unclear. Here, we present new zircon U–Pb ages, isotopic analyses and whole‐rock major‐ and trace‐element data for felsic rocks from west and east Songliao Basin to explore the above question. The granites in Shancheng area formed between 176 and 164 Ma and have εHf(t) values of −22.09 to −7.59 with a TDM2 age range of 3622–2336 Ma. The granites are dominated by adakites and I‐type granite whose primary magma is derived from a thickened ancient crust. The rhyolites in Wushijiazi area formed between 151 and 141 Ma and have εHf(t) values of 3.34–12.38 with a TDM2 age range of 517–1328 Ma. They are A‐type granite and have a flat rare‐earth‐element (REE) pattern with obvious negative Eu anomalies, suggesting they were derived from partial melting of lower crustal rocks. The above findings indicate that the middle–late Jurassic granite in the Shancheng area formed in a compression setting related to the subduction of the Palaeo–Pacific Plate beneath the Eurasian continent and the Late Jurassic to early Cretaceous rhyolites in Wushijiazi area formed in an extensional setting related to the collapse of the Mongol–Okhotsk belt. In combination with regional geologic data, we conclude that the Palaeo–Pacific tectonic system mainly affected the east side of Songliao Basin, while the Mongol Okhotsk tectonic system mainly affected the Erguna Block, through the GXAR to the northern margin of the North China Craton (NCC).

Various magmatisms during the subduction-collision process are crucial to reveal the long-term tectonic evolution of the eastern Central Asian Orogenic Belt. In this paper, we present major and trace elements of whole-rock, zircon U-Pb dating and Hf isotope of the Shanmen pluton. Results imply that the Shanmen pluton consists of quartz diorite and mylonitic granite, with zircon U-Pb ages of 263.7-259.6 Ma. The studied quartz diorite contains high Sr/Y (51.19-90.87) and (La/Yb)(N) (7.82-13.62) ratios, and belongs to adakitic rocks. Coupled with the positive epsilon(Hf)(t) values of thorn5.71 to thorn12.8 with no obvious Eu anomaly, we propose that quartz diorite is the product of the interaction between different degrees of slab melt and the overlying mantle wedge. In contrast, the mylonitic granite has lower MgO (0.28 wt% - 0.47 wt%) contents and positive epsilon(Hf)(t) values of thorn7.79 to thorn10.15, indicating an affinity with I-type granite originated by partial melting of the intermediate-basic lower crust. The geochemical characteristics and lithological assemblages, along with the Permian magmatic rocks in the Changchun-Kaiyuan area displaying arc rocks affinity, propose their formation is related to the southward subduction of the Paleo-Asian Ocean (PAO). Based on this study and previous evidence, we lean towards adopting a middle-late Permian slab break-off model, wherein the PAO did not close until the late Permian.

内蒙古乌拉山地区石榴子石花岗岩内发育大量石榴子石,这些石榴子石中保留着寄主岩石的变质演化历程的重要信息,故明确其成因类型至关重要.前人虽提出其为转熔成因,但未能提供充分证据证明.对此,本文对研究区深熔石榴黑云片麻岩以及石榴子石花岗岩内的石榴子石进行了岩相学以及矿物学研究.结果显示,在野外露头上,低度深熔石榴黑云片麻岩→中度深熔石榴黑云片麻岩的脉体/石榴子石花岗岩,石榴子石粒度逐渐增大,并且当岩石内的脉体小而少时不见粗粒石榴子石,脉体大而多时粗粒石榴子石发育,而石榴子石花岗岩内发育大量的粗粒石榴子石,此外脉体内的石榴子石粒度整体大于基体内的石榴子石粒度.在显微特征上,中度深熔石榴黑云片麻岩的脉体内的石榴子石和石榴子石花岗岩内的石榴子石晶形较差,形态各异,边界呈锯齿状,发育筛状变晶结构,并部分具有核部发育边部不发育的特点,基质内还具有逆反应结构以及斜长石堆晶体.矿物化学特征上,中度深熔石榴黑云片麻岩的脉体内的石榴子石和石榴子石花岗岩内的石榴子石以富Fe、Mg贫Mn、Ca为特点,不发育生长环带,与黑云母接触的石榴子石发育扩散环带,表现为TFeO曲线由中心向两边升高,MgO曲线由中心向两边降低,二者呈负相关.综合分析得出石榴子石花岗岩内的石榴子石是在变质深熔过程中,由固相变质生长至处于深熔熔体包裹状态下继续生长而成,这种石榴子石是转熔成因,为转熔矿物相(相当于残留矿物相),且中度深熔石榴黑云片麻岩的脉体内的石榴子石也具有相同成因,说明二者关系密切,为石榴子石花岗岩是石榴黑云片麻岩高度深熔的产物提供了有力依据.同时大量转熔型石榴子石保留在花岗岩内的现象说明研究区内的花岗岩并未经历长距离运移,故而未达到彻底的固液两相分离,进一步证明了其原地—半原地成因.

This paper reports new geochemical data including zircon U-Pb ages with Hf isotopic data, whole -rock major and trace isotopic compositions for the Early Cretaceous magmatic rocks in the northeastern North China Craton ( NCC), with the purpose of constraining its petrogenesis and tectonic setting. It also provides a basis for further discussion on the formation and evolution of the lithosphere in the northeastern NCC during the Late Mesozoic. Zircons in the Xinglin granite porphyry, Hongtuya andesitic crystal tuff and Jiangyuan rhyolitic breccia-bearing crystal-lithic tuff all show magmatic origin. Zircon U-Pb dating yield age are 130 +/- 1Ma, 128 +/- 1Ma and 120 +/- 1Ma, respectively. The Xinglin granite porphyry and the Hongtuya andesitic crystal tuff have high content of SiO2, Al2O3 Sr, high Na2O/K2O, Sr/Y and ( La/Yb)(N) ratios. In addition, they exhibit low Y and Yb. They are enriched in LILE ( e. g., Ba, Th and U), depleted in HFSE ( e. g., Nb, Ti and P) with weak negative Eu anomalies (delta Eu =0. 82 similar to 0. 94), showing they are typical of adakitic rocks. The Xinglin granite porphyry has high content of total -alkali, low content of TiO2, characterized by peraluminous-weakly peraluminous granite A/CNK = 1. 06 similar to 1. 14, the zircon saturated temperature values of 798 similar to 815 degrees C and a distribution pattern of LREE enrichment with incline to the right, which indicates it is I -type granite. The zircon ( t) values in the Xinglin granite porphyry ranged 17. 96 0. 19, and the two -stage model ages yield t(DM2) = 1197 similar to 2313Ma, which imply that the Xinglin granite porphyry is derived from partial melting of the thickened mafic lower crust of Paleoproterozoic to Mesoproterozoic. The zircon epsilon(Hf)( t) values in the Hongtuya andesitic crystal tuff ranged 3. 37 similar to 5. 47, and the two -stage model ages yield t(DM2) = 830 similar to 967Ma, indicating that the Hongtuya andesitic crystal tuff is a metasomatism product of the Neoproterozoic delaminated eclogite lower crust partial melting and mantle peridotite. Combined with the epsilon(Hf)( t) values in the Jiangyuan rhyolitic breccia-bearing crystal-lithic tuff ranged 2. 69 1. 00, and the two -stage model ages yield t(DM2) = 1115 similar to 1349Ma, we conclude that the epsilon(Hf)( t) values of magmatic rocks are heterogeneous in the southern Jilin Province, and the magmatic source area is characterized by multi -component origin, including both ancient crust and juvenile crust. We supposed that there were two accretion evolution events in the continental crust of the northeastern NCC during Proterozoic. Comprehensive studies have shown that subduction and slab roll -back of the Paleo-Pacific plate ( Izanagi) led to the thickened the northeastern NCC being in an extensional tectonic setting during the Early Cretaceous, and the destruction of the northeastern NCC by delamination occurred spatially from west to east. The partial melting of delaminated lower continental crust resulted in a wide distribution of adakitic rocks.

Mesoproterozoic (-1.3 Ga) magmatism in the North China Craton (NCC) was characterized by diabase sills, while contemporary granitic magmatism was relatively rare, limiting our understanding of the NCC's evolution during this period. In this manuscript, we report newly identified -1.3 Ga S-type granitic plutons in the Shangdu area, the western part of the northern NCC. Based on the results of geochemical, geochronological and zircon in-situ Lu-Hf isotope analyses, we discussed the petrogenesis, tectonic setting of the granitic plutons and the regime that drove the break-up of the NCC from the Columbia supercontinent. The zircon laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating results indicate that these granites were emplaced at some time between 1315 +/- 21 Ma and 1307 +/- 32 Ma. Moreover, the geochemical results show that they have high contents of SiO2 (75.34-76.97 wt%), Al2O3 (12.90-13.61 wt%) and Na2O + K2O (6.21-8.31 wt%), but low MgO (0.09-0.25 wt%) and Mg-# (14-34). The A/CNK ratios varied between 1.10 and 1.28, indicating that the granites belong to the peraluminous series. Furthermore, the existence of Al-rich minerals (e.g., muscovite and garnet) suggests that they are the S-type granites. The -1.3 Ga zircon display negative to slightly positive epsilon(Hf)(t) values (-9.28-3.1) and old two-stage model ages (T-DM2) (3.3-2.1 Ga). The ages of the inherited zircon and Lu-Hf isotope compositions of the -1.3 Ga zircon in the granite are consistent with those of the detrital zircon from Jining complex, the eastern part of the Khondalite Belt. Based on these facts, we infer that the granites in this study derived from the partial melting of the Jining complex. The coeval mafic dykes (in the Yanliao large igneous province) and the Shangdu granite in the north margin of the NCC strongly suggest an extensional setting, which was related to the break-up of the NCC from the Columbia supercontinent. A mantle plume was likely the dominant driver of the break-up and it should have provided heat for the partial melting of Jining complex.

对华北克拉通东北部早白垩世岩浆岩开展锆石U-Pb年代学、岩石地球化学及Hf同位素研究,能约束其岩石成因与构造背景,并为深入探讨晚中生代华北克拉通东北部岩石圈形成与演化提供依据.吉南白山地区的兴林花岗斑岩、红土崖安山质晶屑凝灰岩和江源含角砾流纹质岩屑晶屑凝灰岩的锆石为岩浆成因,结晶年龄分别为130±1Ma、128±1Ma和120±1 Ma.兴林花岗斑岩和红土崖安山质晶屑凝灰岩具高SiO2、Al2 O3、Sr含量及高Na2 O/K2 O,Sr/Y和(La/Yb)N比值,贫Y、Yb,富集LILE(如Ba、Th、U),亏损HFSE(Nb、Ti、P),具有微弱的负铕异常(δEu=0.82～0.94),具埃达克质岩石特征.兴林花岗斑岩富碱,低TiO2含量,铝饱和指数A/CNK=1.06～1.14,表现为右倾型稀土配分模式,全岩锆饱和温度为798～815℃,属I型花岗岩.兴林花岗斑岩εHf(t)介于-17.96～-0.19,两阶段模式年龄tDM2=1197～2313Ma,指示兴林花岗斑岩源自古元古代-中元古代的加厚镁铁质下地壳部分熔融.红土崖安山质晶屑凝灰岩εHf(t)介于3.37～5.47,两阶段模式年龄tDM2=830～967Ma,暗示红土崖安山质晶屑凝灰岩是新元古代拆沉榴辉岩质下地壳部分熔融并交代地幔橄榄岩的产物.结合江源含角砾流纹质岩屑晶屑凝灰岩εHf(t)(-2.69～1.00),两阶段模式年龄tDM2=1115～1349Ma,可知吉南地区早白垩世岩浆岩εHf(t)具有不均一性,岩浆源区存在多组分的特点,既有古老地壳,也存在新生地壳,指示多阶段地壳生长过程,暗示华北克拉通东北部陆壳在元古代演化过程中存在两次增生事件.综合研究表明,早白垩世古太平洋板块(伊泽奈崎)的俯冲回撤导致增厚的华北克拉通东北部地壳整体处于伸展的构造背景下,并自西向东发生拆沉减薄,拆沉下地壳的部分熔融形成区域广泛分布的埃达克质岩石.

Late Neoarchean garnet granites were developed due to wide anatexis in the Baotou area, northern margin of the North China Craton (NCC) Garnet granites are spatially associated with the Late Neoarchean Daqingshan supracrustal rocks (mainly garnetbiotite gneisses) , as indicated by garnet-biotite gneiss and residual minerals occurring in the garnet granites and garnet leucosomes occurring in garnet-biotite gneisses. The garnet granites are heterogeneous and can be further divided into garnet diorite, garnet quartz diorite and garnet granodiorite which can be identified in a geological section near Hadmengou. Petrographic studies show that the garnet granites and anatectic source rocks are similar in mineral association, but are different in their contents. The garnets from the garnet granite and garnet-biotite gneiss are similar in features; they are surrounded by radial biotite flakes, a typical structural indicator of inverse reaction. The anatexis may occur during a period from metamorphic peak isothermal depressurization in a clockwise P-T process, mainly resulting in melting of k-feldspar and biotite. The garnet granites are high in Al2O3 content and have a large variation in CaO content and K2O/Na2O ratio, characterized by enrichment of light REE and large ion lithophile elements and depletion of Nb, Ta, P and Ti, being similar in composition to the garnet-biotite gneisses. However, the garnet granites show variations in compositions, and Eu-enriched and Eu-depleted patterns are considered as a prominent geochemical characteristic of autochthonous and hypautochthonous anatectic granite. Geochronology studies constrainthe anatexis occurring before 2. 43Ga, as a result of subhorizontal detachment structures in the area due to Late Neoarchean tectonothermal event along the northern margin of the NCC.

Despite numerous years and avenues of investigation, the timing, evolution, and mechanism of lithospheric thinning of the North China Craton (NCC) are still highly debated. Late Triassic igneous rocks especially mantle derived mafic rocks could provide critical information related to the post-collisional lithospheric thinning of the Liaodong Peninsula in the eastern NCC. Using newly acquired geochronological data points, we determined that the intrusive rocks have emplacement ages of 219-209 Ma, which are typical of Late Triassic magmatism. The studied Qinghekou gabbros have low SiO2 (49.43-51.86 wt.%), Na2O+K2O (3.59-7.20 wt.%), high MgO (3.70-8.54 wt.%) and transition metal element contents, with Mg-# values ranging from 49.2 to 69.3. While these samples are enriched in large ion lithophile elements such as Rb, Ba, and K and light rare earth elements, they are depleted in high field strength elements such as Nb, Ta, Ti, and P and heavy rare earth elements. We conclude that these gabbros samples were formed in a subduction-related tectonic setting, where the primary magmas were derived from partial melting of the lithospheric mantle that experienced metasomatism via slab-related fluids. Our Tongyuanpu granite samples have I-type granite affinity, as indicated by their high SiO2 (73.60-75.30 wt.%) and low MgO (0.08-0.32 wt.%) contents, as well as the A/CNK values of 0.99-1.25 and the zircon saturated temperature values of 757-832 degrees C, the parental magmas for these granites were generated by partial melting of the lower crust. Combined with the spatio-temporal distribution and rock-assemblages of the Late Triassic intrusive rocks, we conclude that these rocks were formed in an extensional environment characterized by lithospheric thinning caused by lithospheric delamination after the collision between the NCC and the Yangtze Craton. Furthermore, we infer that the initial lithospheric thinning of the eastern NCC occurred during the Late Triassic.

为了解蒙古-鄂霍次克构造体系的远程作用及其在中国东北以南的影响范围,在内蒙古多伦火山盆地羊盘沟地区开展了流纹斑岩锆石U-Pb同位素年代学、岩石地球化学及区域对比研究.结果显示,其形成时代为144.2±0.6 Ma,属于早白垩世早期.主量元素SiO2含量为73.25％～76.72％,K2O含量为4.64％～7.87％,K2O/Na2O值在1.15～3.82之间,A/CNK值为0.79～0.99;副矿物为磁铁矿、锆石和磷灰石等,属准铝质高钾钙碱性-钾玄岩系列A2型流纹岩类;稀土元素总量高(320.76×10-6～415.70×10-6),富集轻稀土元素、大离子亲石元素K和Rb、高场强元素Zr和Hf以及元素U、Th等,亏损重稀土元素、大离子亲石元素Ba和Sr、高场强元素Nb和Ta以及元素P、Ti等,显著Eu负异常(δEu=0.08～0.15).表明流纹斑岩形成于后碰撞构造环境,是早白垩世蒙古-鄂霍次克洋闭合后某个伸展事件下的产物,因此,蒙古-鄂霍次克构造体系在中国的影响范围向东南至少延伸至蒙东南-冀北一带,且对应的蒙古-鄂霍次克洋东段的闭合完成时间应早于144.2 Ma.