Mudanjiang Ocean Research Articles

Petrogenesis and tectonic implications of the Early Jurassic syenogranite in the northern section of Zhangguangcai Range, NE China: insights from geochronology, geochemistry, and Lu-Hf isotopes

The Lesser Xing’an-Zhangguangcai Range tectonic belt in northeastern China is located along the eastern margin of the Central Asian Orogenic Belt and serves as the key to understanding the tectonic transition between the Paleo-Asian Ocean and Paleo-Pacific regimes during the Early Mesozoic. This study presented the zircon U-Pb geochronology, Hf isotope, and whole-rock geochemistry of Early Jurassic syenogranites from the northern Zhangguangcailing Range. The LA-ICP-MS zircon dating result indicates a crystallization age of 194 ± 2 Ma. Integrated with regional data, this study confirmed that the Early Mesozoic magmatism in the region was concentrated in the Early Jurassic (180–200 Ma). The granites displayed typical arc-related features, including (1) high SiO2 (70.59–76.81 wt.%), alkali enrichment (Na2O + K2O = 7.65–8.38 wt.%), low Mg and Fe contents, classifying them as the high-K calc-alkaline metaluminous to weakly peraluminous (A/CNK = 0.99–1.04); (2) strong LREE enrichment with weak Eu anomalies (δEu = 0.44–0.81) and HREE depletion ((La/Yb)N = 3.38–16.17); and (3) enrichment in LILEs (Rb, K) with the corresponding depletion in HFSEs (Nb, Ta, and Ti). Harker diagrams showed negative correlations between SiO2 and MgO, TiO2, CaO, TFeO, P2O5, and Eu, indicating fractional crystallization involving amphibole, ilmenite, apatite, and feldspar. The zircon εHf(t) values (+2.7 to +5.0) and the corresponding Meso-to Neoproterozoic crustal model ages (TDM2 = 915–1067 Ma) suggested that the magma originated from partial melting of the Meso-Neoproterozoic mafic lower crust at amphibolite facies. The geochemical and isotopic data collectively identified these rocks as I-type granite. In a regional tectonic context, their formation was interpreted to reflect an active continental margin environment driven by the westward subduction of the Paleo-Pacific Plate during the Early Jurassic, potentially influenced by the closure of the Mudanjiang Ocean, a branch of the Paleo-Pacific.

Metamorphic evolution of blueschists in the Heilongjiang Complex: Implications for the subduction history of the Mudanjiang Ocean

Metamorphic evolution of blueschists in the Heilongjiang Complex: Implications for the subduction history of the Mudanjiang Ocean

Deformation History of the Heilongjiang Complex and Subduction Polarity of the Mudanjiang Ocean, NE Asia

During the Mesozoic, NE Asia experienced intense tectonic and magmatic activity, including the closure of the Mongol–Okhotsk Ocean (MOO), the subduction and demise of the Mudanjiang Oceanic Plate (MOP), and the continuous westward subduction of the Paleo-Pacific Plate (PPP). The evolution of the MOP remains highly contentious, particularly regarding its final closure timing and subduction polarity, and warrants further investigation. The Heilongjiang Complex (HLC), primarily distributed within the Mudanjiang Suture Zone (MSZ), which separates the Jiamusi and Songnen blocks, preserves key geological records of the Mudanjiang Oceanic subduction and closure. By employing detailed structural analysis, zircon U-Pb dating, and tomographic imaging, we reconstruct the tectonic history of the HLC and propose its five stages of deformation since the Mesozoic. The first stage, which occurs from the Late Triassic to the Early Jurassic, is characterized by SE-dipping schistosity within the HLC. Integrating the identification of the east-dipping remnants of the oceanic lithosphere west of the MSZ by tomographic imaging suggests an eastward subduction of the MOP underneath the Jiamusi Block during the Early Mesozoic. The second stage, spanning the Early Jurassic to the Late Jurassic, is characterized by E–W-striking tight folds associated with the MOO’s SSE-ward subduction and PPP’s NNW-ward subduction. The third stage of deformation, occurring from the Late Jurassic to Early Cretaceous, features S–N-striking box folds, indicative of the final amalgamation of the Jiamusi, Songnen, and Nadanhada terranes. The fourth stage, taking place in the late Early Cretaceous, is marked by near E–W-striking thrust faults that are associated with the closure of the eastern segment of the MOO. Finally, the fifth stage, which follows the Early Cretaceous, involves nearly NE-striking thrust faults related to NW-ward subduction of the PPP.

Late Paleozoic–Early Mesozoic subduction history of Mudanjiang Ocean: New insights from greenschist in the Heilongjiang Complex, NE China

Late Paleozoic–Early Mesozoic subduction history of Mudanjiang Ocean: New insights from greenschist in the Heilongjiang Complex, NE China

Geochronology and Geochemical Characteristics of Granitoids in the Lesser Xing’an–Zhangguangcai Range: Petrogenesis and Implications for the Early Jurassic Tectonic Evolution of the Mudanjiang Ocean

This article focuses on zircon U-Pb isotope dating and a whole-rock elemental analysis of granodiorites, monzonitic granites, granodioritic porphyries, and alkali feldspar granites in the Yangmugang area of the Lesser Xing’an–Zhangguangcai Range. The zircon U-Pb isotope-dating results revealed that these granitic rocks formed during the late Early Jurassic period (182.9–177.2 Ma). Their geochemical characteristics and zircon saturation temperatures suggest that the granodiorites are moderately differentiated I-type granites and the monzonitic granite, granodioritic porphyries, and alkali feldspar granites are highly differentiated I-type granites. The degree of magma differentiation progressively increased from granodiorites to alkali feldspar granites. By combining the regional Nd and Hf isotope compositions, it was inferred that the magma source involved the melting of lower crustal material from the Mesoproterozoic to the Neoproterozoic eras. By integrating these findings with contemporaneous intrusive rock spatial variations, it was indicated that the late Early Jurassic granitoids in the Lesser Xing’an–Zhangguangcai Range formed within an extensional tectonic setting after the collision and closure of the Songnen–Zhangguangcai Range and Jiamusi blocks. Additionally, this study constrains the closure of the Mudanjiang Ocean to the late Early Jurassic period (177.2 Ma).

Spatial and Temporal Exhumation of the Northeastern China: Insights From Low Temperature Thermochronology

ABSTRACTThe northeastern (NE) China has undergone a long‐term tectonic history involving subduction–accretion of the Siberian Craton, North China Craton, and Western Pacific Plate, providing an ideal target for understanding the interactions between cratons and the Pacific oceanic lithosphere. However, the Mesozoic‐Cenozoic geological and topographic evolutions of the NE China remain unclear. Here, we present new apatite fission track data from Precambrian metamorphic rocks in the Lesser Hinggan Mountains. Apatite fission track dating yielded a group of central ages ranging from 130 ± 18 to 151 ± 11 Ma with mean track lengths varying between 13.67 ± 0.13 and 14.49 ± 0.08 μm. Thermal modeling results revealed a rapid cooling event at ca. 165–140 Ma, which was related to compressional deformations driven by shallow subduction of the Paleo‐Pacific Ocean Plate beneath the northeastern China. Furthermore, regional low temperature thermochronological datasets in NE China show additional three rapid exhumation stages, including the Early Jurassic (ca. 200–180 Ma), Early Cretaceous (ca. 120–100 Ma), and Late Cretaceous (ca. 80–60 Ma). They were associated with closure of the Mudanjiang Ocean, slab rollback of the Paleo‐Pacific Plate, and collision between the Okhotomorsk Block and southeastern Asia. As the Cenozoic, slow exhumation has emerged throughout the northeastern China.

Differential Uplift Triggered Basin‐And‐Range System: Evidence From Low‐Temperature Thermochronology in Eastern NE Asia

AbstractSince the Mesozoic, eastern NE Asia has experienced multiple tectonic events, resulting in a complex structure and forming one of the world's largest Meso‐Cenozoic lacustrine basin systems. Presently, basin evolution models require further elucidation regarding the simultaneous generation of diverse rift basins and the potential impact stemming from the closure of the Mudanjiang Ocean, whose oceanic closure demarcated the boundary between the Songliao Basin and the eastern basins, raises questions about its influence on the development of the basin‐and‐range system. To address these questions, we augment new low‐temperature thermochronological data on basement highs separating the eastern NE Asia basins to investigate the shallow‐deep coupling process of tectonic evolution since the Mesozoic. The new cooling age pattern shows non‐overlapping and spatial differences among major basement highs. Inverse thermal modeling revealed five‐stage cooling episodes among the basement highs, but with different onset and cooling rates of each episode, indicating a significant differential uplift mode. A major reburial stage was identified throughout eastern NE Asia during the mid‐Cretaceous. Compiling cooling age patterns and inverse thermal modeling, we note the existence of a proto‐basin covering an area much larger than the previously contemplated “Pan‐Sanjiang” Basin. In general, our study indicates the final closure of the Mudanjiang Ocean occurred at ca. 150–140 Ma. Since the Early Cretaceous, with changes in the subduction direction, two‐stage flat slab subduction of the Paleo‐Pacific plate and the consequent subduction of the Pacific plate co‐dominated the basements' differential uplift and the formation of the eastern NE Asia basin‐and‐range framework.

Tectonic nature, subduction, and closure of the Mudanjiang Ocean: Insights from newly discovered oceanic fragments in the Luobei Heilongjiang Complex

Tectonic nature, subduction, and closure of the Mudanjiang Ocean: Insights from newly discovered oceanic fragments in the Luobei Heilongjiang Complex

Provenance and tectonic setting of the Yimianpo Group in the southeastern Songnen–Zhangguangcai Range Block: constraints on the closure of the Mudanjiang Ocean

Provenance and tectonic setting of the Yimianpo Group in the southeastern Songnen–Zhangguangcai Range Block: constraints on the closure of the Mudanjiang Ocean

Revisiting the Late Paleozoic–Mesozoic tectonic evolution of epicontinental eastern Central Asian Orogenic Belt on the basis of detrital zircon

Revisiting the Late Paleozoic–Mesozoic tectonic evolution of epicontinental eastern Central Asian Orogenic Belt on the basis of detrital zircon

Metamorphism of the Yilan amphibolites from the Heilongjiang Complex and deformation of the granodioritic mylonites from the Jiamusi Massif, Northeastern China

The Heilongjiang Complex records the evolution history of the Mudanjiang Ocean, which is of great significance to constrain the amalgamation process of the Jiamusi and Songnen‐Zhangguangcai Range massifs. We carried out petrological, chronological, geochemical, mineral chemical and electron backscatter diffraction (EBSD) fabric analyses on the Heilongjiang Complex in the Yilan area. The latest zircon U–Pb dating results show that the protolith ages of the amphibolite are 261.3 ± 3.0 Ma and 261.8 ± 3.3 Ma, while that of the granodioritic mylonite is 207.8 ± 2.2 Ma. The amphibolites and granodioritic mylonite are enriched in large‐ion lithophile elements (e.g., Rb, Ba, and Sr) and light rare earth elements, with depletion in high‐field‐ strength elements (e.g., Nb, Ta, Zr, and Hf), indicating that the formation of the protoliths of the amphibolites and granodioritic mylonite is related to the subduction of the Mudanjiang oceanic plate under the Songnen‐Zhangguangcai Range Massif. The amphibolites and granodioritic mylonite both experienced two periods of metamorphic and deformation events. The metamorphic degree of the early period of metamorphism is low amphibolite facies, which records a clockwise P–T path from early increased temperature and pressure to a late isothermal depressurization. The P–T path reveals that this period of metamorphism is associated with the collision between two massifs. The later period of metamorphism reaches low greenschist facies, accompanied by deformation, which may be related to the rapid exhumation of the Heilongjiang Complex. This study provides a new perspective for exploring the collision and collage process of the Jiamusi and Songnen‐Zhangguangcai Range massifs.

Provenance and metamorphic records of forearc sediments from the Heilongjiang Complex, NE China: Implications for subduction erosion associated with the Mudanjiang Ocean

Subduction erosion is widely thought to play a significant role in crustal recycling at modern convergent plate margins. However, identifying subduction erosion in fossil accretionary margins is difficult due to multiple episodes of tectonic superimposition and an absence of direct geophysical evidence. By assessing provenance and metamorphic records in this study, we are the first to document the record of subduction erosion in Late Triassic to Middle Jurassic meta-sedimentary rocks from the Luobei Heilongjiang Complex, NE China. Most detrital zircons from four meta-sedimentary samples have typical core-rim textures. Approximately 90% of the detrital zircon cores yielded Phanerozoic ages with εHf(t) values of +12.8 to −17.6. Geochronological and isotopic comparisons indicate that the meta-sedimentary rocks have a provenance in the eastern Songnen Block and were deposited in a forearc basin. The youngest ages of detrital zircon cores span from 229 to 176 Ma, while the metamorphic ages obtained from detrital zircon rims range from 209 to 185 Ma. Combined with the 186−165 Ma phengite 40Ar-39Ar ages of the meta-sedimentary rocks, this suggests that their protoliths were deposited during the Late Triassic−Middle Jurassic. Mineral inclusions define peak blueschist-facies metamorphism at pressure-temperature conditions of 0.9−1.0 GPa and 359−365 °C; this indicates that forearc sediment from the overriding plate was abraded into the subduction channel and underwent high-pressure metamorphism. Metamorphic ages (209−165 Ma) obtained from phengite and detrital zircon rims suggest that a period of subduction erosion occurred during slab subduction. These results reveal rapid progression from early forearc sedimentation (229−165 Ma) to subduction erosion (209−165 Ma) during westward subduction of the Mudanjiang Ocean.

Permian to Cretaceous tectonic evolution of the Jiamusi and Songliao blocks in NE China: Transition from the closure of the Paleo-Asian Ocean to the subduction of the Paleo-Pacific Ocean

Permian to Cretaceous tectonic evolution of the Jiamusi and Songliao blocks in NE China: Transition from the closure of the Paleo-Asian Ocean to the subduction of the Paleo-Pacific Ocean

Pulsed Mesozoic exhumation in Northeast Asia: New constraints from zircon U-Pb and apatite U-Pb, fission track and (U-Th)/He analyses in the Zhangguangcai Range, NE China

Pulsed Mesozoic exhumation in Northeast Asia: New constraints from zircon U-Pb and apatite U-Pb, fission track and (U-Th)/He analyses in the Zhangguangcai Range, NE China

Lithospheric structure and transformation of the Songnen and Jiamusi blocks in the eastern segment of the Central Asian Orogenic Belt revealed by 3D magnetotelluric inversion

Lithospheric structure and transformation of the Songnen and Jiamusi blocks in the eastern segment of the Central Asian Orogenic Belt revealed by 3D magnetotelluric inversion

ХЕЙЛУНЦЗЯНСКИЙ КОМПЛЕКС – ФРАГМЕНТ ЮРСКОЙ АККРЕЦИОННОЙ ПРИЗМЫ В ТЕКТОНИЧЕСКИХ ОКНАХ ПЕРЕКРЫВАЮЩЕЙ КОНТИНЕНТАЛЬНОЙ ПЛИТЫ: МОДЕЛЬ ПЛОСКОЙ СУБДУКЦИИ

The Circum-Pacific Late Albian-Cenomanian orogenic belts (including the Sikhote-Alin-Western-Sakhalin belt) were formed as a result of the deformation of mainly epioceanic terranes – fragments of Jurassic-Early Cretaceous accretionary wedges with ophiolites and other fragments of oceanic crust, turbidite basins, and island-arc systems. To the west of the Sikhote-Alin - Northern-Sakhalin belt and orthogonally, there are structures of earlier consolidation, which include the Bureya-Jiamusi-Khanka fragment of the orogenic belt of the Late Cambrian-Early Ordovician consolidation of the Late Proterozoic - Cambrian complexes. Within this belt, four isolated outcrops of the Heilongjiang complex are mapped, combining metamorphites of the epidote-amphibolite and glaucophane-schist facies and representing a fragment of an accretionary wedge of the Jurassic age. It was assumed that these outcrops marked the suture, i.e., represented the remains of the closed Mudanjiang paleoocean, separating the original Jiamusi terrane (and the Bureya-Jiamusi-Khanka belt) located to the west of Central Asia structures. The proposed article provides data that the Heilongjiang complex does not mark a suture, but is an underground near-horizontal continuation of the marginal continental accretionary wedge of the Nadanhad - Bikin terrane (flat subduction model) brought to the surface at the site of the antiform bending. The unity of the compared parts of the accretionary wedge is emphasized by the close matrix age, the similarity of detritus zircon populations, and the similarity of the composition and age of allochthonous inclusions (limestone, chert, Late Paleozoic and Early Mesozoic basalt). An important common feature is that Late Paleozoic and Early Mesozoic basalts from allochthonous inclusions in both cases are represented by the N-MORB and OIB types, with no traces of suprasubduction volcanism in the matrix. The Heilongjiang complex forms, according to this interpretation, a tectonic window among the more ancient formations of the Jiamusi terrane. There is no need to assume the existence of the Mudanjiang Ocean to explain the formation of the Heilongjiang complex. The features of the structure of this complex and the conditions of its occurrence can be explained by the processes of flat subduction of the Pacific slab in the Jurassic and its deformation in the Early Cretaceous.

Geochemistry and Zircon U-Pb-Hf Isotopes of Metamorphic Rocks from the Kaiyuan and Hulan Tectonic Mélanges, NE China: Implications for the Tectonic Evolution of the Paleo-Asian and Mudanjiang Oceans

The Late Paleozoic–Early Mesozoic tectonic evolution of the Changchun-Yanji suture (CYS) was mainly associated with the Paleo-Asian and Mudanjiang tectonic regimes. However, the spatial and temporal overprinting and variations of these two regimes remains are still dispute. In order to evaluate this issue, in this contribution, we present new zircon U-Pb ages and a whole-rock geochemical and zircon Hf isotopic dataset on a suite of metamorphic rocks, including gneisses, actinolite schist, leptynites, and biotite schists, from tectonic mélanges in northern Liaoning and central Jilin provinces, NE China. Based on zircon LA-ICP-MS U-Pb dating results, protoliths show wide ranges of aging spectrum, including Paleoproterozoic (2441 Ma), Early Permian (281 Ma), Late Permian (254 Ma), and Late Triassic (230 Ma). The Permian protoliths of leptynites from the Hulan Tectonic Mélange (HLTM) and gneisses from the Kaiyuan Tectonic Mélange (KYTM) exhibit arc-related geochemical signatures, implying that the Paleo-Asian Ocean (PAO) did not close prior to the Late Permian. The Late Triassic protoliths of gneisses from the KYTM, in combination with previously reported coeval igneous rocks along the CYS, comprises a typical bimodal igneous suite in an E–W-trending belt, suggesting a post-orogenic extensional environment. Consequently, we infer that the final closure of the PAO took place during the Early–Middle Triassic. The Early Permian protoliths of biotite schists from the HLTM are alkali basaltic rocks and contain multiple older inherited zircons, which, in conjunction with the geochemical features of the rocks, indicate that they were generated in a continental rift related to the initial opening of the Mudanjiang Ocean (MO). Data from this contribution and previous studies lead us to conclude that the MO probably opened during the Middle Triassic, due to the north–south trending compression caused by the final closure of the PAO.

Opening and closure history of the Mudanjiang Ocean in the eastern Central Asian Orogenic Belt: Geochronological and geochemical constraints from early Mesozoic intrusive rocks

Opening and closure history of the Mudanjiang Ocean in the eastern Central Asian Orogenic Belt: Geochronological and geochemical constraints from early Mesozoic intrusive rocks

Ages and geochemistry of Early Jurassic granitoids in the Lesser Xing’an–Zhangguangcai Ranges, NE China: Petrogenesis and tectonic implications

Abstract Early Jurassic granitoids are widespread in the Lesser Xing’an–Zhangguangcai Ranges, providing excellent targets to understand the late Paleozoic to early Mesozoic tectonic framework and evolution of Northeast China, especially the Jiamusi block and its related structural belts. In this paper, we present new geochronological, geochemical, and isotopic data from the granitoids in the Lesser Xing’an–Zhangguangcai Ranges to constrain the early Mesozoic tectonic evolution of the Mudanjiang Ocean between the Jiamusi and Songnen blocks. Our results show that the granitic intrusions in the Lesser Xing’an–Zhangguangcai Ranges are mainly composed of syenogranite, monzogranite, granodiorite, and tonalite, which have crystallization ages from 196 to 181 Ma. Their geochemical features indicate that these Jurassic intrusions are all high-K calc-alkaline I-type granites with metaluminous to weakly peraluminous compositions. These granitoids are characterized by enrichments in large ion lithophile elements (e.g., Ba, Th, U) and light rare earth elements and depletions in high field strength elements (e.g., Nb and Ta) and heavy rare earth elements, which are typical for continental arc–type granites. The sources of these granitoids were likely derived from juvenile Mesoproterozoic to Neoproterozoic crustal materials (e.g., metabasaltic rocks). Integrated with data from regional coeval magmatism, metamorphism, metallogeny, and structure, our new data suggest that the granitoids in the Lesser Xing’an–Zhangguangcai Ranges were probably formed in an active continental margin setting, which fits well in our previous model of Early Jurassic westward subduction of the Mudanjiang Ocean between the Jiamusi and Songnen blocks.

Geochronology and Geochemistry of Early Cretaceous Granitic Plutons in the Xing'an Massif, Great Xing'an Range, NE China: Petrogenesis and Tectonic Implications

In this study, we present zircon U‐Pb ages, whole‐rock geochemical data and Hf isotopic compositions for the Meiguifeng and Arxan plutons in Xing'an Massif, Great Xing'an Range, which can provide important information in deciphering both Mesozoic magmatism and tectonic evolution of NE China. The zircon U‐Pb dating results indicate that alkali feldspar granite from Meiguifeng pluton was emplaced at ∼145 to 137 Ma, and granite porphyry of Arxan pluton was formed at ∼129 Ma. The Meiguifeng and Arxan plutons have similar geochemical features, which are characterized by high silica, total alkalis, differentiation index, with low P2O5, CaO, MgO, TFe2O3 contents. They belong to high‐K calc‐alkaline series, and show weakly peraluminous characteristics. The Meiguifeng and Arxan plutons are both enriched in LREEs and LILEs (e.g., Rb, Th, U and K), and depleted in HREEs and HFSEs (e.g., Nb, Ta and Ti). Combined with the petrological and geochemical features, the Meiguifeng and Arxan plutons show highly fractionated I‐type granite affinity. Moreover, the Meiguifeng and Arxan plutons may share a common or similar magma source, and they were probably generated by partial melting of Neoproterozoic high‐K basaltic crust. Meanwhile, plagioclase, K‐feldspar, biotite, apatite, monazite, allanite and Ti‐bearing phases fractionated from the magma during formation of Meiguifeng and Arxan plutons. Combined with spatial distribution and temporal evolution, we assume that the generation of Early Cretaceous Meiguifeng and Arxan plutons in Great Xing'an Range was closely related to the break‐off of Mudanjiang oceanic plate. Furthermore, the Mudanjiang Ocean was probably a branch of Paleo‐Pacific Ocean.