Neoproterozoic active margin in the northwestern Yangtze Block, South China: new clues from detrital zircon U–Pb geochronology and geochemistry of sedimentary rocks from the Hengdan Group

2020 ◽  
pp. 1-17
Author(s):  
Bo Hui ◽  
Yunpeng Dong ◽  
Feifei Zhang ◽  
Shengsi Sun ◽  
Shuai He
Keyword(s):  
South China ◽  
Detrital Zircon ◽  
Active Continental Margin ◽  
Geodynamic Setting ◽  
Provenance Analysis ◽  
Yangtze Block ◽  
Essential Information ◽  
Zircon Age ◽  
Age Patterns ◽  
Depositional Age

Abstract The Yangtze Block in South China constitutes an important Precambrian landmass in the present East Asian continent. The Neoproterozoic sedimentary successions of the Hengdan Group in the NW Yangtze Block record essential information for deciphering the Neoproterozoic tectonics along the NW margin. However, its depositional age, provenance and tectonic properties remain uncertain. Here, a combined analysis of detrital zircon U–Pb dating and geochemistry is performed on representative samples from the Hengdan Group. Concordant dating results of samples from the bottom and upper parts constrain the maximum depositional age at c. 720 Ma. Detrital zircon age patterns of samples reveal a uniformly pronounced age peak at c. 915–720 Ma, which is consistent with the magmatic pulses in domains at the NW end of the Yangtze Block. In addition, these samples display left-sloping post-Archaean Australian shale (PAAS)-normalized rare-earth element patterns and variable trace element patterns, resembling sediments accumulated in a basin related to an active continental margin geodynamic setting. Provenance analysis reveals that the main sources featured intermediate to felsic components, which experienced rapid erosion and sedimentation. These integrated new investigations, along with previous compilations, indicate that the Hengdan Group might have been deposited in a fore-arc basin controlled by subduction beneath the Bikou Terrane. Thus, such interpretation further supports proposals for subduction-related tectonics along the western margin of the Yangtze Block during the early Neoproterozoic.

Neoproterozoic Jiangnan Orogeny in southeast Guizhou, South China: evidence from U–Pb ages for detrital zircons from the Sibao Group and Xiajiang Group

2016 ◽  
Vol 53 (3) ◽  
pp. 219-230 ◽  
Author(s):  
Xiao Ma ◽  
Kunguang Yang ◽  
Xuegang Li ◽  
Chuangu Dai ◽  
Hui Zhang ◽  
...  
Keyword(s):  
South China ◽  
Detrital Zircon ◽  
Inductively Coupled Plasma ◽  
Detrital Zircons ◽  
North India ◽  
Yangtze Block ◽  
Inductively Coupled ◽  
Two Samples ◽  
Southeastern Margin ◽  
Depositional Age

The Jiangnan Orogeny generated regional angular unconformities between the Xiajiang Group and the underlying Sibao Group in the western Jiangnan Orogen along the southeastern margin of the Yangtze Block in southeast Guizhou, South China. Laser ablation – inductively coupled plasma – mass spectrometry (LA–ICP–MS) U–Pb zircon dating of two samples of the Motianling granitic pluton yielded U–Pb zircon ages of 826.2 ± 3.4 and 825.5 ± 6.1 Ma, with an average age of 825.6 ± 3.0 Ma, which is considered the minimum depositional age of the Sibao Group. The U–Pb ages of the youngest detrital zircon grains from the Sibao Group and the Xiajiang Group yielded average ages of 834.9 ± 3.8 and 794.6 ± 4.2 Ma, respectively. The depositional age of the Sibao Group can be constrained at 825–835 Ma, and deposition of the Xiajiang Group did not begin before ca. 800 Ma. These results suggest that the Jiangnan Orogeny, which led to the assembly of the Yangtze and Cathaysia blocks, ended at 795–835 Ma on the western segment of the Jiangnan Orogen. The detrital zircon distribution spectrums of the Sibao and Xiajiang groups suggest a provenance from Neoproterozoic basement sedimentary sequences along with a mixture of local Neoproterozoic subduction-related felsic granitoids, distant plutons from the western Yangtze Block and eastern Jiangnan Orogen, and recycled materials from the interior of the Yangtze Block. By comparing the basin evolution histories and magmatic and metamorphic events along the continental margins of the Rodinia supercontinent, it is proposed that the South China Block might have been located at the periphery, adjacent to North India and East Antarctica, rather than in the interior of Rodinia in Neoproterozoic time.

Caledonian terrane amalgamation of Svalbard: detrital zircon provenance of Mesoproterozoic to Carboniferous strata from Oscar II Land, western Spitsbergen

2013 ◽  
Vol 150 (6) ◽  
pp. 1103-1126 ◽  
Author(s):  
DETA GASSER ◽  
ARILD ANDRESEN
Keyword(s):  
Detrital Zircon ◽  
Large Scale ◽  
Strike Slip ◽  
Western Coast ◽  
Zircon Age ◽  
The North ◽  
Tectonic History ◽  
Icp Ms ◽  
Depositional Age ◽  
Sveconorwegian Orogen

AbstractThe tectonic origin of pre-Devonian rocks of Svalbard has long been a matter of debate. In particular, the origin and assemblage of pre-Devonian rocks of western Spitsbergen, including a blueschist-eclogite complex in Oscar II Land, are enigmatic. We present detrital zircon U–Pb LA-ICP-MS data from six Mesoproterozoic to Carboniferous samples and one U–Pb TIMS zircon age from an orthogneiss from Oscar II Land in order to discuss tectonic models for this region. Variable proportions of Palaeo- to Neoproterozoic detritus dominate the metasedimentary samples. The orthogneiss has an intrusion age of 927 ± 3 Ma. Comparison with detrital zircon age spectra from other units of similar depositional age within the North Atlantic region indicates that Oscar II Land experienced the following tectonic history: (1) the latest Mesoproterozoic sequence was part of a successor basin which originated close to the Grenvillian–Sveconorwegian orogen, and which was intruded byc. 980–920 Ma plutons; (2) the Neoproterozoic sediments were deposited in a large-scale basin which stretched along the Baltoscandian margin; (3) the eclogite-blueschist complex and the overlying Ordovician–Silurian sediments probably formed to the north of the Grampian/Taconian arc; (4) strike-slip movements assembled the western coast of Spitsbergen outside of, and prior to, the main Scandian collision; and (5) the remaining parts of Svalbard were assembled by strike-slip movements during the Devonian. Our study confirms previous models of complex Caledonian terrane amalgamation with contrasting tectonic histories for the different pre-Devonian terranes of Svalbard and particularly highlights the non-Laurentian origin of Oscar II Land.

The tectonic setting of the eastern margin of the Sino-Korean Block inferred from detrital zircon U–Pb age and Nd isotope composition of the Pyeongan Supergroup (upper Palaeozoic – Lower Triassic), Korea

2017 ◽  
Vol 156 (3) ◽  
pp. 471-484 ◽  
Author(s):  
MUN GI KIM ◽  
YONG IL LEE ◽  
TAEJIN CHOI ◽  
YUJI ORIHASHI
Keyword(s):  
Detrital Zircon ◽  
Isotope Composition ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Lower Triassic ◽  
Zircon Age ◽  
Nd Isotope ◽  
Eastern Margin ◽  
Late Palaeozoic ◽  
Nd Isotope Composition

AbstractThe upper Palaeozoic succession (Pyeongan Supergroup) in central eastern Korea is well correlated with the equivalent successions distributed in North China, suggestive of the Korean upper Palaeozoic being part of the Sino-Korean Block. Detrital zircon U–Pb ages and Sm–Nd isotope compositions of the Pyeongan Supergroup in the Samcheok coalfield of the Taebaeksan Basin were analysed. A single predominant zircon age peak at c. 1.9 Ga (> 70%) is marked in all sedimentary units, followed by varying amounts of minor late Palaeozoic grains (up to 30%). The rarity of Meso- to Neoproterozoic- and Silurian-aged zircons confirms that sediment influx from the South China and Qinling blocks was insignificant. The 2.0–1.8 Ga-dominated zircon age pattern and the Nd isotope composition (average εNd(0) = −15.5±4.0) of the Pyeongan Supergroup most closely reflect the signature of the Yeongnam Massif basements, which supports a previous hypothesis that the Pyeongan Supergroup was mostly derived from a palaeo-orogen located to the east–southeast. Relatively higher εNd(0) values (> −10.1) in the lowermost and the upper parts of the succession are closely matched by the increased occurrence of syn-depositional-aged zircons, which indicates considerable mixing of juvenile materials at c. 320 Ma and 260 Ma. Both arc-related magmatic events are interpreted to have been related to oceanic subduction, suggesting that the eastern margin of the Sino-Korean Block was an active continental margin during late Palaeozoic times.

scholarly journals Detrital zircon age patterns from turbidites of the Balagne and Piedmont nappes of Alpine Corsica (France): Evidence for an European margin source

2018 ◽  
Vol 722 ◽  
pp. 69-105 ◽  
Author(s):  
Wei Lin ◽  
Philippe Rossi ◽  
Michel Faure ◽  
Xian-Hua Li ◽  
Wenbin Ji ◽  
...  
Keyword(s):  
Detrital Zircon ◽  
Zircon Age ◽  
Age Patterns

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.

The mid-Cretaceous transition from basement to cover within sedimentary rocks in eastern New Zealand: evidence from detrital zircon age patterns

2012 ◽  
Vol 150 (3) ◽  
pp. 455-478 ◽  
Author(s):  
CHRISTOPHER J. ADAMS ◽  
NICK MORTIMER ◽  
HAMISH J. CAMPBELL ◽  
WILLIAM L. GRIFFIN
Keyword(s):  
New Zealand ◽  
Detrital Zircon ◽  
Passive Margin ◽  
Accretionary Wedge ◽  
Sediment Sources ◽  
Eastern Province ◽  
Zircon Age ◽  
Source Areas ◽  
Western Province ◽  
Age Patterns

AbstractDetrital zircon U-Pb ages for 30 Late Jurassic and Cretaceous sandstones from the Eastern Province of eastern New Zealand, combined with previously-published geochronological and palaeontological data, constrain the time of deposition in the Pahau and Waioeka terranes of the Cretaceous accretionary margin of Zealandia, and their adjacent cover strata. The zircon age patterns also constrain possible sediment source areas and mid-Cretaceous geodynamic models of the transition from basement accretionary wedge to passive-margin cover successions. Pahau Terrane deposition was mainly Barremian to Aptian but continued locally through to late Albian time, with major source areas in the adjacent Kaweka and Waipapa terranes and minor inputs from the inboard Median Batholith. Waioeka Terrane deposition was mainly Albian, with distinctive and exclusive sediment sources, principally from the Median Batholith but with minor inputs from the Western Province. Alternative tectonic models to deliver such exclusive Median Batholith and Western Province-derived sediment to the mid-Cretaceous Zealandia continental margin are: (1) the creation of a rift depression across Zealandia or (2) sinistral displacement of South Zealandia with respect to North Zealandia, to expose Western Province rocks directly at the Zealandia margin. Detrital zircon age patterns of Cretaceous cover successions of the Eastern Province of eastern New Zealand demonstrate purely local sources in the adjacent Kaweka and Waipapa terranes. Cretaceous zircon components show a decline in successions of late Early Cretaceous age and disappear by late Late Cretaceous time, suggesting the abandonment or loss of access to both the Median Batholith and Western Province as sediment sources.

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