scholarly journals Supplemental Material: Transition from a passive to active continental margin setting for the NE Asian continental margin during the Mesozoic: Insights from the sedimentary formations and paleogeography of the eastern Jiamusi Massif, NE China

Author(s):  
Yini Wang ◽  
Wenliang Xu ◽  
et al.

Zircon U-Pb data and zircon Hf isotopic data.

Author(s):  
Yini Wang ◽  
Wenliang Xu ◽  
Feng Wang

The Mesozoic tectonic evolution of the NE Asian continental margin has received much attention in recent years. However, previous studies focused mainly on the petrogenesis of igneous rocks and their relationship with Mesozoic tectonics, and there have been few studies of the Mesozoic sedimentary formations of the NE Asian continental margin. We combined zircon U-Pb ages with Hf isotopic and biostratigraphic data to reconstruct the Mesozoic paleogeography of the NE Asian continental margin. The results indicate that Mesozoic strata of the eastern Jiamusi Massif, NE China, include the Upper Triassic Nanshuangyashan Formation (Norian), Lower Jurassic volcanic rocks, and Lower Cretaceous Longzhaogou Group. The Upper Triassic Nanshuangyashan Formation consists of a suite of alternating marine and terrestrial sedimentary rocks with abundant fossils that formed in a passive continental margin setting. The Lower Jurassic strata comprise a suite of calc-alkaline volcanic rocks that include basaltic andesites, andesites, and rhyolites that formed in an active continental margin setting related to initial subduction of the Paleo-Pacific Plate beneath Eurasia. The Lower Cretaceous Longzhaogou Group belong to alternating marine and terrestrial sedimentary formations that formed in an active continental margin setting related to subduction of the Paleo-Pacific Plate. Here, we integrate these data to reconstruct the Mesozoic tectonic history of the NE Asian continental margin, which comprises a Late Triassic passive continental margin, the initiation of subduction of the Paleo-Pacific Plate in the Early Jurassic, and westward subduction and rollback of the Paleo-Pacific Plate in the Early Cretaceous.


Lithos ◽  
2021 ◽  
Vol 400-401 ◽  
pp. 106422
Author(s):  
Sakine Moradi ◽  
Shao-Yong Jiang ◽  
Eric H. Christiansen ◽  
Mohammad Reza Ghorbani

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1023
Author(s):  
Hyojong Lee ◽  
Min Gyu Kwon ◽  
Seungwon Shin ◽  
Hyeongseong Cho ◽  
Jong-Sun Kim ◽  
...  

Zircon U-Pb geochronology and bulk-rock geochemistry analyses were carried out to investigate their relationship with depositional environments of the non-marine Neungju Basin sediments in South Korea. The Neungju Basin was formed in an active continental margin setting during the Late Cretaceous with associated volcanism. Detrital zircon age distributions of the Neungju Basin reveal that the source rocks surrounding the basin supplied sediments into the basin from all directions, making different zircon age populations according to the depositional environments. Mudstone geochemistry with support of detrital zircon U-Pb age data reveals how the heterogeneity affects the geochemical characteristics of tectonic setting and weathering intensity. The sediments in the proximal (alluvial fan to sandflat) and distal (playa lake) environments differ compositionally because sediment mixing occurred exclusively in the distal environment. The proximal deposits show a passive margin signature, reflecting their derivation from the adjacent metamorphic and granitic basement rocks. The distal deposits properly indicate an active continental margin setting due to the additional supply of reworked volcaniclastic sediments. The proximal deposits indicate a minor degree of chemical weathering corresponding to fossil and sedimentological records of the basin, whereas the distal deposits show lower weathering intensity by reworking of unaltered volcaniclastic detritus from unstable volcanic and volcaniclastic terranes. Overall, this study highlights that compositional data obtained from a specific location and depositional environments may not describe the overall characteristic of the basin.


2006 ◽  
Vol 78 (1) ◽  
pp. 133-149 ◽  
Author(s):  
Umberto G. Cordani ◽  
Allen P. Nutman ◽  
Antonio S. Andrade ◽  
José F. Santos ◽  
Maria do Rosário Azevedo ◽  
...  

New SHRIMP U-Pb zircon ages for the Portalegre and Alcáçovas orthogneisses document a complex pre- Variscan history for the Iberian basement in Portugal. The available geochemical and geochronological data for the Alcáçovas orthogneiss (ca. 540 Ma) tend to favor its involvement in a Cadomian orogenic event. This is consistent with the development of an active continental margin setting at the end of the Proterozoic and supports a Gondwanan provenance for the Iberian crust. On the other hand, the Ordovician emplacement age obtained for the magmatic precursors of the Portalegre orthogneisses (497±10 Ma) provides additional evidence for the occurrence of rift-related magmatic activity during the Lower Paleozoic.


2019 ◽  
Vol 157 (4) ◽  
pp. 677-689 ◽  
Author(s):  
Binsong Zheng ◽  
Chuanlong Mou ◽  
Renjie Zhou ◽  
Xiuping Wang ◽  
Zhaohui Xiao ◽  
...  

AbstractPermian–Triassic boundary (PTB) volcanic ash beds are widely distributed in South China and were proposed to have a connection with the PTB mass extinction and the assemblage of Pangea. However, their source and tectonic affinity have been highly debated. We present zircon U–Pb ages, trace-element and Hf isotopic data on three new-found PTB volcanic ash beds in the western Hubei area, South China. Laser ablation inductively coupled plasma mass spectrometry U–Pb dating of zircons yields ages of 252.2 ± 3.6 Ma, 251.6 ± 4.9 Ma and 250.4 ± 2.4 Ma for these three volcanic ash beds. Zircons of age c. 240–270 Ma zircons have negative εHf(t) values (–18.17 to –3.91) and Mesoproterozoic–Palaeoproterozoic two-stage Hf model ages (THf2) (1.33–2.23 Ga). Integrated with other PTB ash beds in South China, zircon trace-element signatures and Hf isotopes indicate that they were likely sourced from intermediate to felsic volcanic centres along the Simao–Indochina convergent continental margin. The Qinling convergent continental margin might be another possible source but needs further investigation. Our data support the model that strong convergent margin volcanism took place around South China during late Permian – Early Triassic time, especially in the Simao–Indochina active continental margin and possibly the Qinling active continental margin. These volcanisms overlap temporally with the PTB biocrisis triggered by the Siberian Large Igneous Province. In addition, our data argue that the South China Craton and the Simao–Indochina block had not been amalgamated with the main body of Pangea by late Permian – Early Triassic time.


Minerals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 266
Author(s):  
Vera A. Trunilina ◽  
Andrei V. Prokopiev

This paper reports the results of a study of magmatic rocks with Sn–W–Au–Ag mineralization from the Kuranakh, Elikchan, and Istekh ore fields in the Northern batholith belt of the north-eastern Verkhoyansk–Kolyma orogenic belt in Eastern Russia. Using petrographic, mineralogical, geochemical, and isotopic methods, we determined the mineral compositions, petrochemistry, and geochemistry of magmatic rocks, the P–T conditions of their generation and crystallization, and their geodynamic affinity. The studied magmatic rocks have common geochemical characteristics that likely reflect the influence of fluids supplied from a long-lived, deep-seated mantle source. The ore fields are characterized by Sn–W–Au–Ag–Pb polygenetic mineralization. The magmatic and metallogenic evolution comprised five stages for the formation of magmatic rocks and ores. During the first stage (Berriasian–Barremian), arc-related magmatic rocks formed in an active continental margin setting and were associated with Au–Ag mineralization. The second, third, and fourth stages (Aptian–Campanian) took place in a crustal extension and rift setting, and were accompanied by Au–Ag and Sn–W mineralization. During the fifth (post-magmatic) stage, Sn–Ag–Sb and Pb–Ag mineralization occurred.


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