Late Mesozoic metallogeny and intracontinental magmatism, southern Great Xing'an Range, northeastern China

Mesozoic volcanic rocks are widespread throughout the Great Xing'an Range of northeastern China. However, there has been limited investigation into the age and petrogenesis of the Mesozoic volcanics in the eastern Great Xing'an Range. According to our research, the volcanic rocks of the Dayangshu Basin, eastern Great Xing'an Range are composed mainly of trachybasalt, basaltic andesite, and basaltic trachyandesite, with minor intermediate-basic pyroclastic rocks. In this study, the geochemistry and geochronology of the Mesozoic volcanic rocks are presented in order to discuss the petrogenesis and tectonic setting of the Ganhe Formation in the Dayangshu Basin. Zircon U-Pb dating by laser ablation inductively coupled plasma-mass spectrometry indicates that the Mesozoic lavas formed during the late Early Cretaceous (114.3-108.8 Ma). This suite of rocks exhibits a range of geochemical signatures indicating subduction-related genesis, including: (i) calcalkaline to high-K calc-alkaline major element compositions; (ii) enrichment of large ion lithophile elements (e.g. Rb, Ba, K) and light rare earth elements (LREEs/HREEs =7.33-9.85); and (iii) weak depletion in high field strength elements (e.g. Nb, Ta, Ti). Furthermore, Sr-Nd-Pb isotopic data yield initial 87 Sr/ 86 Sr values of 0.70450-0.70463, positive ε Nd (t) values of +1.8 to +3.3, and a mantle-derived lead isotope composition. Combined with the regional tectonic evolution, the results of this study suggest that the Ganhe Group lavas are derived from decompression melting of a metasomatized (enriched) lithospheric mantle, related to asthenospheric upwelling, which resulted from lithospheric mantle delamination and produced extension of the continental margin following the subduction of the Paleo-Pacific Plate.

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“…; Ouyang et al . ). Due to the subduction of the Paleo‐ Pacific Plate, eastern China was in a compressional environment during Jurassic time.…”

Section: Discussionmentioning

confidence: 97%

Petrogenesis and geodynamic significance of the Ganhe Formation lavas, eastern Great Xing'an Range, China: Evidence from geochemistry and geochronology

Sun

Bai

et al. 2016

Island Arc

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“…Published 3D and syn‐collisional magmatism models show that the subducting oceanic slab broke off and/or the lower crust underwent thickening after continental collision (Davies & von Blanckenburg, ; Dewey & Burke, ; Van Hunen & Allen, ), which potentially led to upwelling of the asthenosphere in the post‐orogenic extensional stage (Bonin, Azzouni‐Sekkal, Bussy, & Ferrag, ; Fan et al, ) and porphyry Cu–Mo mineralization in the GXR. Sr–Nd isotopes of Late Jurassic granitoids from the central‐southern GXR indicate that the melting of a subducted slab was probably affected by seawater at an earlier time (Ouyang et al, and references therein; Wu et al, ). Hence, we infer that the Late Jurassic–initial Early Cretaceous (165–138 Ma) volcanism in the CGXR was associated with the closure of the MOO (Figure d).…”

Section: Discussionmentioning

confidence: 99%

“…Late Mesozoic magmatism in the northern GXR is thought to have been controlled mainly by either the MOO or the PP tectonic domain (Dong et al, ; Sui et al, ; Wang et al, ), or a combination of the two (Li et al, ). In contrast, synchronous magmatism in the southern GXR is considered to have been influenced exclusively by the PP tectonic domain (Zhang et al, ), the far‐field effects of the MO tectonic domain (He et al, ; Yang, Niu, Cheng, Shan, & Li, ), or the transformation between the MO and PP tectonic domains (Liu, Zhou, et al, ; Ouyang, Mao, Zhou, & Su, ). A consensus has not been reached in regard to which tectonic domain dominated Early Mesozoic volcanism in the central GXR (CGXR) due to a paucity of volcanic age data that would allow comparison between the southern PAO tectonic domain (Shi et al, ; Yang et al, ; Yu, ) and the northern MO tectonic domain (Li, Chung, et al, 2017; Xu et al, ).…”

Section: Introductionmentioning

confidence: 99%

Timing and evolution of Mesozoic volcanism in the central Great Xing'an Range, northeastern China

et al. 2018

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In this paper, we report on LA‐ICP‐MS zircon U–Pb dates of 14 Mesozoic volcanic rocks from the central Great Xing'an Range (CGXR). These data are integrated with the temporal and spatial distribution of local magmatism‐related Mesozoic mineralization, in an effort to develop an understanding of the geodynamic evolution of the region. Periodic magmatic events in the GXR date from ~1,703 through ~145 Ma. Mesozoic volcanism in the CGXR can be subdivided into three episodes: Triassic (250–205 Ma), Early–Middle Jurassic (182–165 Ma), and Late Jurassic–Early Cretaceous (155–115 Ma). A revision of the previously defined volcanic sequence is offered using a combination of our zircon U–Pb ages and published Mesozoic geological and geophysical evidence from northeast China. We propose that (a) Early–Middle Triassic volcanism in the CGXR resulted from subduction of the Paleo‐Asian oceanic plate; (b) Late Triassic volcanism was related to subduction of the Mongol–Okhotsk oceanic plate (especially near the Erguna Block) and subsequent extension after the closure of the Paleo‐Asian Ocean; (c) Early–Middle Jurassic volcanism was mainly controlled by the southward subduction of the Mongol–Okhotsk oceanic plate; (d) Late Jurassic–initial Early Cretaceous magmatism was initiated by closure of the Mongol–Okhotsk Ocean; and (e) late Early Cretaceous volcanism was induced following the final closure of the Mongol–Okhotsk Ocean and rollback of the Paleo‐Pacific oceanic plate.

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“…Recent research within the GXR has focused on Late Paleozoic and Late Mesozoic events (Sorokin, Kotov, Sal'nikova, Kudryashov, & Kovach, ; Wu et al, , ; W. Xu et al, ), including magmatism, metallogenesis, and tectonism in the northern and southern GXR (Gou et al, ; Hao et al, ; Ouyang, Mao, Zhou, & Su, ; Qin et al, ; Zeng et al, ). However, few researchers have studied the Early Mesozoic volcanic rocks in the GXR due to poor exposure.…”

Section: Introductionmentioning

confidence: 99%

Geochronology, petrogenesis, and tectonic setting of Late Triassic volcanic rocks of the Hadataolegai Formation, central Great Xing'an Range, Northeast China

et al. 2018

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In this study, new geochemical, zircon U–Pb, and Lu–Hf isotopic data are presented for volcanics from the Hadataolegai Formation of the central Great Xing'an Range (GXR) in Northeast China. These new data offer insights into the petrogenesis of the volcanics of the Hadataolegai Formation and the tectonic evolution of the Paleo–Asian Ocean (PAO) and Mongol–Okhotsk Ocean (MOO). These volcanics of the Hadataolegai Formation are divided into andesite‐trachyandesites and dacite‐trachydacites. Zircon U–Pb ages show that the volcanics of the Hadataolegai Formation erupted between 230 Ma and 228 Ma during the Late Triassic, which agrees with recently obtained data. The volcanic rocks in this study have low Y (9.9–21.1 ppm) and Yb (0.78–2.02 ppm) contents, high Sr (444–954 ppm) contents, and slight Eu anomalies (δEu = 0.82 to 0.94), similar to ‘adakite‐like’ rocks. The dacites were formed by fractional crystallization of coeval andesitic magmas. The zircons within the andesite and trachyandesite yield higher positive εHf(t) values (+6.3 to +12.0) and model ages (TDM2) between 860 Ma and 453 Ma, which indicates that the magmas were generated by a newly accreted continental crustal source. Moreover, some of the volcanics are relatively high in MgO contents. These characteristics indicate that the volcanic magmas were derived from the partial melting of delaminated lower crust and mixing with mantle materials. Combining these data with previous studies, we suggest that the magmatism in the central GXR was governed by extension due to the closure of the PAO and the back‐arc extension associated with the southward subduction of the MOO plate (western GXR, near the Erguna Block).

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Late Mesozoic metallogeny and intracontinental magmatism, southern Great Xing'an Range, northeastern China

Cited by 192 publications

References 122 publications

Petrogenesis and geodynamic significance of the Ganhe Formation lavas, eastern Great Xing'an Range, China: Evidence from geochemistry and geochronology

Petrogenesis and geodynamic significance of the Ganhe Formation lavas, eastern Great Xing'an Range, China: Evidence from geochemistry and geochronology

Timing and evolution of Mesozoic volcanism in the central Great Xing'an Range, northeastern China

Geochronology, petrogenesis, and tectonic setting of Late Triassic volcanic rocks of the Hadataolegai Formation, central Great Xing'an Range, Northeast China

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