Discovery of the Early Paleozoic post-collisional granites in northern margin of the Erguna massif and its geological significance

2005 ◽  
Vol 50 (23) ◽  
pp. 2733-2743 ◽  
Author(s):  
Wu Guana ◽  
Sun Fengyue ◽  
Zhao Caisheng ◽  
Li Zhitong ◽  
Zhao Ailin ◽  
...  
Keyword(s):  
Early Paleozoic ◽  
Geological Significance ◽  
Northern Margin ◽  
Erguna Massif

scholarly journals Origin and age of the Shenshan tectonic mélange in the Jiangshan-Shaoxing-Pingxiang Fault and late Early Paleozoic juxtaposition of the Yangtze Block and the West Cathaysia terrane, South China

2021 ◽  
Author(s):  
Lijun Wang ◽  
Kexin Zhang ◽  
Shoufa Lin ◽  
Weihong He ◽  
Leiming Yin
Keyword(s):  
South China ◽  
Strike Slip ◽  
Carbonaceous Shale ◽  
Early Paleozoic ◽  
Yangtze Block ◽  
The West ◽  
Northern Margin ◽  
The North ◽  
Tectonic Mélange ◽  
Different Parts

When and how the Yangtze Block (Yangtze) and the West Cathaysia terrane (West Cathaysia) in South China were amalgamated are critical to a better understanding of the Neoproterozoic to early Paleozoic tectonic evolution of South China and remain highly debatable. A key to this debate is the tectonic significance of the Jiangshan-Shaoxing-Pingxiang (JSP) Fault, the boundary between Yangtze and West Cathaysia. The Shenshan mélange along the JSP Fault has the typical block-in-matrix structure and is composed of numerous shear zone-bounded slivers/lenses of rocks of different types and ages that formed in different tectonic environments, including middle to late Tonian volcanic and volcanogenic sedimentary rocks (turbidite) of arc/back-arc affinity, a series of middle Tonian ultramafic to mafic plutonic rocks of oceanic island basalt affinity, a carbonaceous shale that was deposited in a deep marine environment, and a red mudstone. U-Pb zircon ages and acritarch assemblages (Leiosphaeridia-Brocholaminaria association) found in the turbidite confirm its Tonian age, and fossils from the carbonaceous shale (Asteridium-Comasphaeridium and Skiagia-Celtiberium-Leiofusa) constrains its age to the Early to Middle Cambrian. Field relationships and available age data leave no doubt that the ultramafic-mafic rocks are exotic blocks (rather than intrusions) in the younger metasedimentary rocks. We conclude that the Shenshan mélange is not an ophiolitic mélange, but rather a tectonic mélange that formed as a result of movement along the JSP Fault in the early Paleozoic. We suggest that Yangtze and West Cathaysia were two separate microcontinents, were accreted to two different parts of the northern margin of Gondwana in the early Early Paleozoic, and juxtaposed in the late Early Paleozoic through strike-slip movement along the JSP Fault. We further suggest that the ca. 820 Ma collision in the Jiangnan Orogen took place between Yangtze and a (micro)continent that is now partly preserved as the Huaiyu terrane and was not related to West Cathaysia. We compare our model for South China with the accretion of terranes in the North American Cordillera and propose a similar model for the relationship between the Avalon and Meguma terranes in the Canadian Appalachians, i.e., the two terranes were accreted to two different parts of the Laurentian margin and were later juxtaposed through margin-parallel strike slip faulting.

scholarly journals Ordovician mafic magmatism in an Ediacaran arc complex, Sibak, northeastern Iran: the eastern tip of the Rheic Ocean

2018 ◽  
Vol 55 (10) ◽  
pp. 1173-1182 ◽  
Author(s):  
Fereshteh Ranjbar Moghadam ◽  
Fariborz Masoudi ◽  
Fernando Corfu ◽  
Seyed Massoud Homam
Keyword(s):  
Indirect Evidence ◽  
Arc Magmatism ◽  
Early Paleozoic ◽  
Northern Margin ◽  
Rheic Ocean ◽  
Late Precambrian ◽  
Sedimentary Sequences ◽  
Appalachian Orogen ◽  
Laurentian Margin ◽  
Clastic Sedimentary

The assembly of Gondwana in the Ediacaran was concluded by extensive arc magmatism along its northern margin. Extensional events in the early Paleozoic led to rifting and the eventual separation of terranes, which were later assimilated in different continents and orogens. The Sibak area of northeastern Iran records these events, including late Precambrian volcanic-sedimentary processes, metamorphism, and magmatism. A granite at Chahak in the Sibak Complex yields a zircon U–Pb age of 548.3 ± 1.1 Ma, whereas a spatially associated gabbro has an age of 471.1 ± 0.9 Ma. The latter corresponds to the earliest stages of rifting in the nearby Alborz domain, with the deposition of clastic sedimentary sequences, basaltic volcanism, and, as indicated by indirect evidence, coeval granitic plutonism. The Chahak gabbro is thus one of the earliest witnesses of the rifting processes that eventually led to the development of the Rheic Ocean and were indirectly linked to subduction of Iapetus at the Laurentian margin and the early development of the Appalachian orogen.

Geochronology, geochemistry and geological significance of Early Paleozoic volcanic rocks in northern East Ujimqin Banner, Inner Mongolia

2020 ◽  
Vol 36 (4) ◽  
pp. 1107-1126
Author(s):  
YANG ZeLi ◽  
◽  
HU XiaoJia ◽  
WANG ShuQing ◽  
XIN HouTian ◽  
...  
Keyword(s):  
Inner Mongolia ◽  
Volcanic Rocks ◽  
Early Paleozoic ◽  
Geological Significance
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