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.-B.,Chinese Academy of Geological Sciences | Tong Y.-B.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.,Capital Normal University | Wang H.,Chinese Academy of Geological Sciences | And 4 more authors.
Tectonophysics | Year: 2015

Paleomagnetic studies were conducted on the Eocene and Oligocene strata at the western part of the Chuan Dian Fragment in order to describe the crustal deformation induced by continuous penetration of the Indian plate into Eurasia during the late Cenozoic. High-temperature magnetic components with unblocking temperatures of ~680°C were isolated, and positive fold and/or reversal tests reveal the primary nature of the magnetization. The tilt-corrected site-mean directions obtained from the Oligocene and middle-early Eocene strata are, respectively, Ds =200.9°, Is =-31.3°, k =52.8, α 95 =7.7° and Ds =29.7°, Is =32.0°, k =44.9, α 95 =5.6°. Comparison of these results with previous paleomagnetic data from the Chuan Dian Fragment shows that the western and central parts of the Chuan Dian Fragment experienced ~20° integral clockwise rotation relative to East Asia since the middle Miocene. However, the eastern part of the Chuan Dian Fragment has experienced different rotational deformation relative to East Asia since the Pliocene, because of the intense regional crustal deformation and activity on fault systems. The eastern boundary of the Chuan Dian Fragment was bounded by the Yuanmou-Luezhijiang left lateral strike-slip fault prior to the Pliocene, and then substituted by the Xiaojiang left lateral strike-slip fault since the Pliocene, due to the eastwards spreading of the clockwise rotational movement of the Chuan Dian Fragment. The evolutionary characteristics of the Ailaoshan-Red River and Xianshuihe-Xiaojiang strike-slip faults were controlled by the difference between the clockwise rotational extrusion velocities of the Chuan Dian Fragment and the Indochina Block. © 2015 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.


Gao L.,Chinese Academy of Geological Sciences | Yang Z.,Chinese Academy of Geological Sciences | Yang Z.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Tong Y.,Chinese Academy of Geological Sciences | And 3 more authors.
Journal of Geodynamics | Year: 2015

Cretaceous, Paleogene, and Miocene sandstones were sampled in the Jinggu area to constrain the internal deformation of the Lanping-Simao Terrane of the Indochina Block. The tilt-corrected overall site-mean direction of the middle Cretaceous strata recorded in the Jinggu area is Ds/Is=77.0°/43.0°, with α95=2.9° (N=47), with a positive fold test indicating a primary remanence acquisition. The site-mean direction recorded for the high-temperature component of the Miocene strata is Ds/Is=13.7°/36.0°, with α95=3.3° (n=38). The best-fit linear regressions between regional tectonic lines and rotation degree from each sampled area in the Lanping-Simao Terrane indicate a direct relationship between tectonic rotation and formation of the sinusoidal shape of the Lanping-Simao arcuate structural zone. The large clockwise rotation in the Jinggu area can be subdivided into three periods. During the formation of the sinusoidal shape of the Lanping-Simao Arc, the Jinggu area and the Indochina Block experienced approximately 20° of clockwise rotation. An additional ~40° of clockwise rotation in the Jinggu area was caused by bending of the Chongshan-Lancang-Chiang Mai belt between 27 and 20Ma. After the early Miocene, a significant small-scale internal rotation (8.2±3.2°) adjustment occurred in the Jinggu area. Quantitative comparison between the paleomagnetically determined clockwise rotation and tectonic-metamorphic events suggests that the Lanping-Simao Arc was formed by the west-to-east compression and southeastward extrusion of the Shan-Thai Terrane since 36Ma in southeast Tibet. © 2015 Elsevier Ltd.


Tong Y.-B.,Chinese Academy of Geological Sciences | Tong Y.-B.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | Yang Z.-Y.,Chinese Academy of Geological Sciences | Yang Z.-Y.,Key Laboratory of Paleomagnetism and Tectonic Reconstruction | And 6 more authors.
Chinese Journal of Geophysics (Acta Geophysica Sinica) | Year: 2014

Detailed paleomagnetic and rock magnetic studies were carried out on the Cretaceous red beds at the Weishan and Wuyin area in the middle part of Simao Tarrane . High-temperature magnetic components were isolated from the two study areas and the positive fold test shows its primary nature of magnetization. The tilt corrected site-mean direction of the Upper Cretaceous from the Weishan section and the Lower Cretaceous from the Wuyin section is Ds=64.3°, Is=48.5°, k=54.6, α95=4.7° and Ds=15.4°, Is=44.8°, k=212.0, α95=4.6°, respectively. The correlation analysis between the declination changing and the tectonic line changing of Simao Terrane shows that the different rotational deformation of Simao Terrane was controlled by the formation of arcuate structure zone of Simao terrane. According to the active history of the huge strike-slip fault zones in the southeast edge of Tibet plateau, the wasp waist structure of the middle part of Simao Terrane was formed in two tectonic deformation stages. The early stage was related to the NNE stress between the Indian Plate and the Eurasia Plate. The later stage was induced by the southward rotational extrusion movement of Chuandian Terrane. The Weishan and Wuyin area moved about 10.5°±6.0° and 3.8°±4.9° southward respectively relative to the stable area of South China Block. The analysis of the inclination shows that the Wuyin sampling area displaced about 3.4°±5.0° and 3.1°±5.4° northward relative to the Weishan area and Pu'er area, respectively, indicating large crustal shorting occurred between the Wuyin area and the the Weishan area since the collision of India/Eurasia.


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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