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

2021 ◽  
Author(s):  
Yini Wang ◽  
Wenliang Xu ◽  
Feng Wang
Keyword(s):  
Continental Margin ◽  
Lower Cretaceous ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Lower Jurassic ◽  
Pacific Plate ◽  
Upper Triassic ◽  
Passive Continental Margin ◽  
Ne China ◽  
Margin Setting

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.

Andesite Geochemistry Features of Late Triassic Tumugou Formation, in Zhongdian, Yunnan Province

2012 ◽  
Vol 524-527 ◽  
pp. 16-23
Author(s):  
Jian Guo Huang ◽  
Run Sheng Han ◽  
Ren Tao ◽  
Zhi Qiang Li
Keyword(s):  
Trace Element ◽  
Volcanic Rock ◽  
Continental Margin ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Distribution Patterns ◽  
Island Arc ◽  
Late Triassic ◽  
Magma Source ◽  
Volcanic Arc

The Late Triassic Tumugou Formation volcanic rocks which belongs to typical island arc volcanic rocks in southern end of Yidun island arc belt is located at the eastern of the Zhongdian ,NW Yunnan, SW China. The volcanic rocks can be divided into three categories:andesitic basalt, andesite, quartz andesite, etc. Through geochemical analysis the major elements, rare earth ele and trace element in volcanic rocks, SiO255.18-57.59×10-2,TiO21.16-1.45×10-2,Na2O+K2O5.11-8.05×10-2.consider it is calc-alkaline- alkaline Series of high-K andesite, volcanic may be controlled by the crystal fractionation of magma.Rb31.50-101×10-6,Ba1310-12300×10-6,Nb/Ta11.4-15.5,REE166.07-240.78×10-6,δEu0.74-1.00,REE distribution patterns show oblique to the HREE side and enrichment in LREE .Eu anomaly is not obvious. It is can see from the relevant figure about trace element, it is very similar in magmatic distribution patterns between volcanic rock and Volcanic-arc rock, indicating that the volcanic in this area may be formed in volcanic-arc environment. From east to west, Magma source depth have regular change with the really thickness of mainland shell. Explain that Tumugou Formation volcanic rock is subduction by Ganzi- Litang Ocean basin from east to west. Hongshan-Ousaila region of eastern edge of Zhongdian is the volcanic island arc system during the passive continental margin into an active continental margin.

scholarly journals Relationships between Alluvial Facies/Depositional Environments, Detrital Zircon U-Pb Geochronology, and Bulk-Rock Geochemistry in the Cretaceous Neungju Basin (Southwest Korea)

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1023
Author(s):  
Hyojong Lee ◽  
Min Gyu Kwon ◽  
Seungwon Shin ◽  
Hyeongseong Cho ◽  
Jong-Sun Kim ◽  
...  
Keyword(s):  
Continental Margin ◽  
Detrital Zircon ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Depositional Environments ◽  
Source Rocks ◽  
Bulk Rock ◽  
Zircon Age ◽  
Margin Setting ◽  
Weathering Intensity

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.

Proapocritus lini sp. nov., a new ephialtitid wasp (Hymenoptera: Apocrita) from the Middle-Upper Jurassic of Daohugou, NE China

2020 ◽  
Vol 3 (1) ◽  
pp. 054-058
Author(s):  
HAICHUN ZHANG
Keyword(s):  
Lower Cretaceous ◽  
Late Jurassic ◽  
Upper Jurassic ◽  
Lower Jurassic ◽  
Ne China ◽  
Basal Group

The Ephialtitidae is an extinct family of wasps, with 29 genera reported from the Lower Jurassic-Lower Cretaceous in Kyrgyzstan, Kazakhstan, China, Mongolia, Russia, Spain, Germany and Brazil, and flourished in the Middle–Late Jurassic (Meunier, 1903; Rasnitsyn, 1975, 1977, 1990, 1999, 2008a, b; Zessin, 1981, 1985; Zhang, 1986; Darling & Sharkey, 1990; Rasnitsyn & Ansorge, 2000; Rasnitsyn & Martínez-Delclòs, 2000; Zhang et al., 2002; Rasnitsyn et al., 2003; Rasnitsyn & Zhang, 2004, 2010; Zhang et al., 2010; Ding et al., 2013, 2016; Li et al., 2013, 2014, 2015; Zhang et al., 2014). It is considered to be the most basal group of the Apocrita, one of two suborders of the order Hymenoptera (Rasnitsyn & Zhang, 2010).

scholarly journals Hydrogeological dissimilarity of geodynamically different terranes

2021 ◽  
Vol 44 (2) ◽  
pp. 134-140
Author(s):  
V. E. Glotov
Keyword(s):  
Continental Margin ◽  
Sandy Loam ◽  
Active Continental Margin ◽  
Passive Continental Margin ◽  
Coarse Grained ◽  
Active Margin ◽  
Water Abundance ◽  
Fine Grained ◽  
Weathering Processes

The article presents and analyzes the data on ground waters of active (suprapermafrost) and hindered (subpermafrost) water exchange of geodynamically different terrains in order to prove the hydrogeological importance of their historical and tectonic characteristics. On the example of Trans-Polar Chukotka it is shown that, under suprapermafrost conditions, the ubiquitous eluvial-deluvial nappes are the most water-abundant on the terrane – a fragment of the passive continental margin, whereas they are the least water-abundant on the terrains of the active margin. Hydrogeological situation changes under subpermafrost conditions: more permeable and water-retaining rocks compose the terranes of the active margin. These differences are associated with the level of rock tectonic decompaction and, accordingly, with different intensity of weathering processes in the terrane rocks of different geodynamic origin in suprapermafrost and subpermafrost conditions. The hypergenesis zone on the terranes of the passive continental margin features coarse-grained rock weathering products accumulated in relatively calm geological and historical environments, the aggregate is sandy. The terranes of the active margin, which underwent long-term subvertical and subhorizontal displacements contain more fine-grained weathering products; the aggregate includes sandy loam and clay sand. Since the permafrost strata in both Trans-Polar Chukotka and Eastern Siberia is greater than the depth of hypergene transformations, the terranes of the active continental margin, the rocks of which were impacted by tectonic decompaction processes, mainly of a strike-slip and thrust nature, feature greater water abundance in subpermafrost conditions.

scholarly journals Evidence from the Kyrenia Range, Cyprus, of the northerly active margin of the Southern Neotethys during Late Cretaceous–Early Cenozoic time

2011 ◽  
Vol 149 (2) ◽  
pp. 264-290 ◽  
Author(s):  
ALASTAIR H. F. ROBERTSON ◽  
KEMAL TASLI ◽  
NURDAN İNAN
Keyword(s):  
Continental Margin ◽  
Carbonate Platform ◽  
Middle Eocene ◽  
Active Continental Margin ◽  
Volcanic Rocks ◽  
Basaltic Rocks ◽  
Tectonic Model ◽  
The North ◽  
Basic Volcanic ◽  
Upper Maastrichtian

AbstractSedimentary geology and planktonic foraminiferal biostratigraphy have shed light on the geological development of the northern, active continental margin of the Southern Neotethys in the Kyrenia Range. Following regional Triassic rifting, a carbonate platform developed during Jurassic–Cretaceous time, followed by its regional burial, deformation and greenschist-facies metamorphism. The platform was exhumed by Late Maastrichtian time and unconformably overlain by locally derived carbonate breccias, passing upwards into Upper Maastrichtian pelagic carbonates. In places, the pelagic carbonates are interbedded with sandstone turbidites derived from mixed continental, basic volcanic, neritic carbonate and pelagic lithologies. In addition, two contrasting volcanogenic sequences are exposed in the western-central Kyrenia Range, separated by a low-angle tectonic contact. The first is a thickening-upward sequence of Campanian–Lower Maastrichtian(?) pelagic carbonates, silicic tuffs, silicic lava debris flows and thick-bedded to massive rhyolitic lava flows. The second sequence comprises two intervals of basaltic extrusive rocks interbedded with pelagic carbonates. The basaltic rocks unconformably overlie the metamorphosed carbonate platform whereas no base to the silicic volcanic rocks is exposed. Additional basaltic lavas are exposed throughout the Kyrenia Range where they are dated as Late Maastrichtian and Late Paleocene–Middle Eocene in age. In our proposed tectonic model, related to northward subduction of the Southern Neotethys, the Kyrenia platform was thrust beneath a larger Tauride microcontinental unit to the north and then was rapidly exhumed prior to Late Maastrichtian time. Pelagic carbonates and sandstone turbidites of mixed, largely continental provenance then accumulated along a deeply submerged continental borderland during Late Maastrichtian time. The silicic and basaltic volcanogenic rocks erupted in adjacent areas and were later tectonically juxtaposed. The Campanian–Early Maastrichtian(?) silicic volcanism reflects continental margin-type arc magmatism. In contrast, the Upper Maastrichtian and Paleocene–Middle Eocene basaltic volcanic rocks erupted in an extensional (or transtensional) setting likely to relate to the anticlockwise rotation of the Troodos microplate.

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