Key Laboratory of Paleomagnetism and Tectonic Reconstruction

Beijing, China

Key Laboratory of Paleomagnetism and Tectonic Reconstruction

Beijing, China
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Zhang S.-H.,Chinese Academy of Geological Sciences | Zhang S.-H.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Zhao Y.,Chinese Academy of Geological Sciences | Zhao Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | And 4 more authors.
Earth and Planetary Science Letters | Year: 2017

The Yanliao rift zone in the northern North China Craton (NCC) is the location of the standard section for late Paleoproterozoic–Mesoproterozoic stratigraphy in China and is associated with the emplacement of large volumes of diabase sills. Detailed field investigations show that the sills are distributed over a region that is >600 km long and >200 km wide, with areal extent >1.2×105 km2 and cumulative thickness of the sills in any one area ranging from 50 m to >1800 m. High-resolution secondary ion mass spectrometry (SIMS) baddeleyite dating shows that emplacement of these sills occurred between about 1330 and 1305 Ma with a peak age of 1323 Ma. Emplacement of these diabase sills was accompanied by pre-magmatic uplift that started at about 1.35–1.34 Ga as indicated by the disconformity between the Changlongshan and Xiamaling formations and absence of sedimentation after the Xiamaling Formation in some areas. All the diabase sills exhibit similar geochemical features of tholeiitic compositions with intraplate characteristics. Given a relatively short duration of emplacement at 1.33–1.30 Ga, along with the large areal extent and volume, as well as intraplate character, this magmatic province constitutes a large igneous province (LIP). This Yanliao LIP and the accompanying pre-magmatic uplift were related either to a mantle plume and/or continental rifting during breakup of the NCC from the Nuna (Columbia) supercontinent. Paleomagnetic, ash bed and LIP data and other geological constraints suggest that the NCC had a close connection with Siberia, Laurentia, Baltica, North Australia and India crustal blocks. In particular, the most direct age match between the 1.33–1.30 Ga Yanliao LIP and the 1.33–1.30 Ga Derim Derim–Galiwinku LIP of the North Australian Craton (NAC), as well as the similarities between the late Paleoproterozoic–Mesoproterozoic stratigraphic units of the Yanliao rift in the NCC with the southeastern McArthur Basin in the NAC, indicate that the Yanliao and Derim Derim–Galiwinku events are fragmented parts of the same LIP, supporting the paleomagnetically plausible idea that the NCC and NAC were connected (or at least near neighbors) during the early Mesoproterozoic period. © 2017 Elsevier B.V.


Zhang S.-H.,Chinese Academy of Geological Sciences | Zhang S.-H.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Zhao Y.,Chinese Academy of Geological Sciences | Zhao Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Liu Y.,Wuhan University
Precambrian Research | Year: 2017

The Bayan Obo in the northern North China Craton (NCC) is the world's largest light rare earth element (LREE) deposit and is hosted in carbonatite sills emplaced into sedimentary rocks of the Bayan Obo Group. However, the timing and genesis of the Bayan Obo deposit has been highly controversial for many decades. Here we report a precise zircon 208Pb/232Th age of 1301 ± 12 Ma (N = 47, mean square of weighted deviates [MSWD] = 2.2) for a REE-Nb-rich carbonatite sill from the Bayan Obo deposit. Zircon morphology, trace element compositions and mineral inclusions demonstrate that these zircons were crystallized from REE-Nb-rich carbonatitic magmas and their ages represent the timing of carbonatites and REE-Nb mineralization. The newly obtained age of ca. 1.30 Ga is consistent with field observations of the Bayan Obo REE-Nb deposit and successfully explains why the carbonatites and REE-Nb mineralization in the Bayan Obo deposit occurred mainly in the Jianshan Formation and that no carbonatites and REE-Nb mineralization were identified from the rocks overlying the Jianshan Formation. The new results demonstrate that the Bayan Obo REE-Nb deposit is a product of mantle-derived carbonatite magmatism at ca. 1.30 Ga. Field relations show that emplacement of the Bayan Obo carbonatites was accompanied by pre-magmatic uplift that is considered to be related to rift-to-drift transition. The Bayan Obo carbonatites and REE-Nb deposit are spatially and temporally linked with the newly identified 1.33–1.30 Ga Yanliao large igneous province (LIP) in the northern NCC and were related to continental rifting that have led to breakup of the NCC from the Columbia (Nuna) supercontinent. © 2017 Elsevier B.V.


Tong Y.,Chinese Academy of Geological Sciences | Tong Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.,Capital Normal University | Pei J.,Chinese Academy of Geological Sciences | And 4 more authors.
Gondwana Research | Year: 2017

The Late Cretaceous location of the Lhasa Terrane is important for constraining the onset of India-Eurasia collision. However, the Late Cretaceous paleolatitude of the Lhasa Terrane is controversial. A primary magnetic component was isolated between 580 °C and 695 °C from Upper Cretaceous Jingzhushan Formation red-beds in the Dingqing area, in the northeastern edge of the Lhasa Terrane, Tibetan Plateau. The tilt-corrected site-mean direction is Ds/Is = 0.9°/24.3°, k = 46.8, α95 = 5.6°, corresponding to a pole of Plat./Plon. = 71.4°/273.1°, with A95 = 5.2°. The anisotropy-based inclination shallowing test of Hodych and Buchan (1994) demonstrates that inclination bias is not present in the Jingzhushan Formation. The Cretaceous and Paleogene poles of the Lhasa Terrane were filtered strictly based on the inclination shallowing test of red-beds and potential remagnetization of volcanic rocks. The summarized poles show that the Lhasa Terrane was situated at a paleolatitude of 13.2° ± 8.6°N in the Early Cretaceous, 10.8° ± 6.7°N in the Late Cretaceous and 15.2° ± 5.0°N in the Paleogene (reference point: 29.0°N, 87.5°E). The Late Cretaceous paleolatitude of the Lhasa Terrane (10.8° ± 6.7°N) represented the southern margin of Eurasia prior to the collision of India-Eurasia. Comparisons with the Late Cretaceous to Paleogene poles of the Tethyan Himalaya, and the 60 Ma reference pole of East Asia indicate that the initial collision of India-Eurasia occurred at the paleolatitude of 10.8° ± 6.7°N, since 60.5 ± 1.5 Ma (reference point: 29.0°N, 87.5°E), and subsequently ~ 1300 ± 910 km post-collision latitudinal crustal convergence occurred across the Tibet. The vast majority of post-collision crustal convergence was accommodated by the Cenozoic folding and thrust faulting across south Eurasia. © 2017 International Association for Gondwana Research


Zhang S.-H.,Chinese Academy of Geological Sciences | Zhang S.-H.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Zhao Y.,Chinese Academy of Geological Sciences | Zhao Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | And 3 more authors.
Lithos | Year: 2017

Baddeleyite has been recognized as a key mineral to determine the crystallization age of silica-undersaturated igneous rocks. Here we report a new occurrence of baddeleyite identified from REE-Nb-Th-rich carbonatite in the world's largest REE deposit, Bayan Obo, in the North China Craton (China). U-Th-Pb dating of three baddeleyite samples yields crystallization ages of 310–270 Ma with the best estimated crystallization age of ca. 280 Ma. These ages are significantly younger than the ca. 1300 Ma Bayan Obo carbonatites, but broadly coeval to nearby Permian granitoids intruding into the carbonatites. Hence, the Bayan Obo baddeleyite did not crystallize from the carbonatitic magma that led to the formation of the Bayan Obo carbonatites and related REE-Nb-Th deposit. Instead, it crystallized from hydrothermal fluids and/or a reaction involving zircon and dolomite during contact metamorphism related to the Permian granitoid emplacement. This is in agreement with the results of electron microprobe analysis that show humite inclusions in baddeleyite, since humite is a typical magnesian skarn mineral and occurs in close proximity to the intrusive contacts between carbonatites and granitoids. Our results show that baddeleyite can be used for dating hydrothermal and contact metamorphic processes. © 2017 Elsevier B.V.


Tong Y.,Chinese Academy of Geological Sciences | Tong Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.,Capital Normal University | Mao C.,Hohai University | And 4 more authors.
Earth and Planetary Science Letters | Year: 2017

A primary magnetic component with the acquisition time of 56.0–43.2 Ma was isolated between 580 °C and 685 °C from the Eocene Gonjo and Ranmugou Formations in the eastern part of the Qiangtang Terrane, Tibetan Plateau. The tilt corrected site-mean direction is Ds=35.5°, Is=29.3°, k=45.9, α95=3.2°. The site-mean inclination increased from 29.3° to 41.6° after multiple inclination shallowing corrections, giving a paleopole of 57.9°N/192.1°E, A95=2.9°. Comparison of the Paleogene paleomagnetic data for the Qiangtang Terrane and Lhasa Terrane reveals that both terranes experienced latitudinal crustal shortening before 54–43 Ma, indicating the uplift of southern and central Tibet in the early Eocene. Subsequently, since 35.4 ± 2.4 Ma, the north of the Qiangtang Terrane experienced ∼1300 ± 410 km of crustal shortening, indicating the uplift of the northern Tibetan Plateau. The Lhasa Terrane and Qiangtang Terrane have not experienced further crustal shortening since the late Eocene, and the southeastern part of Tibet cannot have provided abundant crustal material to accommodate the significant crustal southward extrusion in the southeastern edge of the Tibetan Plateau. The crust of the Tengchong Terrane and Shan–Thai Block did not experience significant southward extrusion since the late Oligocene–Early Miocene. The Indochina Block was situated in the north of the Qiangtang Terrane before the Oligocene, and since the early Oligocene, the Indochina Block began to experience southward extrusion from the north of the Qiangtang Terrane, which absorbed part of the crustal shortening in the north of the Qiangtang Terrane. © 2017 Elsevier B.V.


Yuan W.,Nanjing University | Yuan W.,Sinopec | Yang Z.,Nanjing University | Yang Z.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.,Chinese Academy of Geological Sciences
Gondwana Research | Year: 2015

The relationship between the Alashan Terrane and North China is a contentious issue given the discovery of allochthonous detrital zircons in Middle Ordovician flysch sandstones from the southwestern Ordos Margin and the large differences in palaeolatitudes between the North China and Tarim cratons. We have collected a suite of Middle to Late Devonian sedimentary rocks from the Niushoushan Mountains at the southeastern margin of the Alashan Terrane, adjacent to the western margin of the Ordos Basin of the North China Craton (NCC). U-Pb dating and Lu-Hf isotopic studies were carried out on detrital zircons from these rocks. The zircon U-Pb ages define five age populations: 0.4-0.7Ga (peak at 488Ma), 1.0-1.3Ga (peaks at 1001 and 1152Ma), 1.5-1.8Ga, 2.4-2.8Ga (prominent peak at 2506Ma and secondary peaks at 2668 and 2796Ma) and >3.0Ga (peak at 3332Ma). One detrital zircon yielded a Hadean age of 4022±17Ma. Zircons with U-Pb age spectra of 2.4-2.7 and >3.0Ga and their corresponding εHf(t) values are significantly different from those in the NCC, indicating that these detrital zircons are not from the NCC, which implies that the Alashan Terrane was not part of North China until the Middle to Late Devonian. U-Pb age spectra of zircons dated at 1.0-1.3Ga, 2.4-2.7Ga, and >3.0Ga, and their corresponding Hf isotope data, have a strong similarity with zircons from East Gondwana and the South China Craton. © 2013 International Association for Gondwana Research.


Jing X.-Q.,Nanjing University | Yang Z.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.,Chinese Academy of Geological Sciences | Tong Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | And 2 more authors.
Precambrian Research | Year: 2015

The paleogeographic relationship between South China and Australia during the Neoproterozoic is still hotly debated. Although a series of propositions for the close proximity between South China and Australia are suggested, their relative positions are varied. To better constrain the paleoposition of South China, we have carried out a new paleomagnetic study from the Neoproterozoic Liantuo Formation in two localities, Yichang and Changyang, in Hubei province, China. Stepwise thermal demagnetization reveals that a late Cretaceous remagnetization (component 'L', 350-500°C) was removed from most of the samples. A medium component ('M') isolated mainly between 350°C and 600°C, but in some cases with an upper limit of 640°C, yields a mean direction of Dg=59.5°, Ig=64.6°, α95=3.7° in situ; and Ds=81.6°, Is=61.5°, α95=4.1° after tilt correction. A steeper medium-high temperature component, 'B', was separated from 71 specimens with almost the same temperature range of 'M' (Dg=341.3°, Ig=78°, α95=5.6° in situ; and Ds=78.3°, Is=83.8°, α95=6.9° after tilt correction) and is similar to the 'B' component obtained by Evans et al. (2000). In addition, a high temperature component 'H' (Ds=102.5°, Is=62.4°, α95=3.7° after tilt correction) with both reversed and normal polarity was revealed up to 690°C, yielding a pole at 12.7°N, 157.4°E, with dp/dm=4.5°/5.8°. A change of magnetic polarity, with 5 magnetozones defined, is revealed in our sampling section, in which a reversed-normal polarity succession in the upper part of the section may be correlative with that obtained in a section 6.5km away by Evans et al. (2000), demonstrating the primary nature of the 'H' component. Combining our results with those of Evans et al. (2000) yields a grand mean pole from the upper Liantuo Formation at 13.2°N and 155.2°E with A95=5.3°. Considering the distribution of our sampling sites, and together with the results of a detailed recent SIMS U-Pb zircon study on the Liantuo Formation in the Three Gorges area (Lan et al., 2015), an age of 720Ma was assigned to component 'H' and its corresponding pole. After carefully reevaluating the Neoproterozoic apparent polar wander paths (APWP) from Australia and South China, we suggest that the South China block was located to the northwest of Northern Australia during the Ediacaran period. Subsequently, the South China block moved to the northwest of Western Australia through counter-clockwise rotation of the Northern Australian craton at the later time of 550Ma, or in the middle Cambrian. © 2015 Elsevier B.V.


Xu H.,CAS Institute of Geology and Geophysics | Xu H.,University of Chinese Academy of Sciences | Yang Z.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.,Chinese Academy of Geological Sciences | And 3 more authors.
Precambrian Research | Year: 2014

Several new paleomagnetic and geological studies focused on the reconstruction of the North China Craton (NCC) within the Paleo-Mesoproterozoic Columbia supercontinent. In spite of these new data, there are still widely divergent opinions regarding supercontinental reconstructions. In addition to qualitative correlations of orogenic belts, rift basin ages, stratigraphy and distribution of igneous provinces, paleomagnetic data can provide key constraints on the positioning of individual cratons on the globe. In this paper, we report a detailed paleomagnetic study on the coeval ~1780Ma mafic dyke swarm and Xiong'er volcanic province, which extended for more than one thousand kilometers in the central NCC. Rock magnetic studies, including thermomagnetic curves, hysteresis loops and the progressive acquisition of isothermal remanence conducted in selected samples, indicate that the dominant magnetic carriers are PSD magnetite. Stepwise thermal demagnetization isolated higher-temperature components directed to NNE/SSW with shallow inclinations from 37 sampling sites (16 sites in Yinshan area, 13 sites in Taihang area and 8 sites in Xiaoshan area). A baked contact test conducted on two Yinshan dykes intruded by a younger dyke demonstrates the magnetization in the Yinshan dykes pre-dates 1320Ma. The existence of dual-polarity magnetizations in both Taihang and Xiong'er areas support our contention that the ChRM was acquired during the cooling of the magma. The primary origin of the ChRM is also supported by a positive fold test on the Xiong'er data, and a coherent regional test between the results from the Taihang and Xiong'er areas. Two different site-mean directions were compiled from these new results along with previous publications. The first direction, from the Taihang and Xiong'er areas, yields Declination (D)/Inclination (I)=12.4°/-3.7° (κ=20.5, α95=4.3°, N=57 sites). The second, from the Yinshan area is at (D) 36.7°/(I)-12.4° (κ=86.8, α95=2.7°, N=32 sites). We argue that the difference is due to Mesozoic and/or Cenozoic vertical-axis rotation of the Taihang and Xiong'er areas with respect to the fixed Yinshan-Ordos basin. The corresponding paleopoles for the Yinshan dykes falls at 245.2°E/35.5°N (A95=2.4°). A comparison between the NCC, Laurentia, Siberia and Baltica is consistent with possible links between these four blocks in a perhaps, even larger, continent. The proximity of Australia and India to the NCC is also evaluated. © 2014 Elsevier B.V.


Yuan W.,Nanjing University | Yang Z.-Y.,Nanjing University | Yang Z.-Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction
Geological Bulletin of China | Year: 2012

U-Pb geochronology and Lu-Hf isotopic studies of detrital zircons from middle Cambrian sediments of Niushoushan area, eastern Hexi Corridor, show three major groups of U-Pb age: 0.6-0.8Ga (peak at 669Ma), 1.0-1.3Ga (peak at 1173Ma), and 1.6-1.8Ga (peak at 1710Ma), which are significantly different from the detrital zircons U-Pb age spectrum of the upper strata in the Hexi Corridor belt. The characteristics of the detrital zircon U-Pb age spectra and Hf isotopes indicate that the detrital zircons 1.0-1.3Ga and 1.7-1.75Ga in age might have originated from southwest Australia, which is consistent with the evidence of paleontological and paleomagnetic studies in the Hexi Corridor. The Jinning-age (0.8-1.0Ga) detrital zircons that appear in the middle Ordovician strata in Hexi Corridor may indicate the changes of the source area of detrital materials, which resulted from the expansion of the North Qilian Ocean. The detrital zircons 0.4-0.5Ga in age extracted from post Ordovician strata were probably produced by the uplift of Qilian orogenic belt as well as the erosion and weathering processes in the Hexi Corridor.


Yuan W.,Nanjing University | Yuan W.,Sinopec | Yang Z.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.,Chinese Academy of Geological Sciences
Journal of Asian Earth Sciences | Year: 2014

Rock magnetic and paleomagnetic studies have been carried out on the early Carboniferous limestones and the Late Permian purple sandstones sampled in the eastern Alashan Terrane (ALT), northwest of China. Two components were isolated from the Early Carboniferous limestone by thermal progressive demagnetisation: a low unblocking temperature component (LTC) of recent origin; a pre-folding medium temperature component (MTC) (the paleomagnetic pole is λ = 13.1°N, F{cyrillic} = 11.0°E, A95 = 7.0°) that is probably the result of the hydrothermal fluids from the Qilian Orgenic Belt acquired during the Late Carboniferous-Early Permian. Also, two components were separated from the Late Permian purple sandstone by thermal progressive demagnetisation: the LTC with the recent viscous remanent magnetisation, and the higher temperature component (HTC) revealed from three sections which has passed a regional fold test at the 95% probability level and reversal test, suggesting a primary characteristic magnetisation. The corresponding paleomagnetic pole is λ = 27.2° N, F{cyrillic} = 18.8° E, A95 = 12.0°. The apparent polar wander path (including early Carboniferous, late Carboniferous-Early Permian, Late Permian and Early-middle Triassic poles) of the ALT is significantly different with those of the NCB. Comparison of the APWPs between the ALT and NCB shows a strong similarity. If the APWP of Hexi Corridor-Alashan rotated counterclockwise around an Euler pole at 44°N, 84°E by 32°, then the coeval APW path of the ALT overlaps to that of the NCB. This result indicates that the ALT migrated to the NCB after the Early-Middle Triassic along a tectonic boundary located between Helanshan Mountain and Zhuozishan Mountain, and finally amalgamated to the NCB before the Early Cretaceous. © 2014 Elsevier Ltd. All rights reserved.

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