scholarly journals Geochemical features, sources and geodynamic settings of accumulation of the cambrian sedimentary rocks of the Mel’gin trough (Bureya continental massif)

2019 ◽  
Vol 64 (5) ◽  
pp. 503-519
Author(s):  
R. O. Ovchinnikov ◽  
A. A. Sorokin ◽  
V. P. Kovach ◽  
A. B. Kotov
Keyword(s):  
Continental Margin ◽  
Active Continental Margin ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Igneous Rocks ◽  
Early Cambrian ◽  
Relative Probability ◽  
Early Proterozoic ◽  
Geodynamic Settings ◽  
Probability Plots

The first data about geochemical features of the Cambrian sedimentary rocks of the Mel’gin trough of the Bureya continental Massif, as well as ages of detrital zircons of them are obtained. It is established, that among the detrital zircons from the sandstones of the Chergilen and Allin formations of the Mel’gin trough zircons with Late Riphean (peaks on relative probability plots – 0.78, 0.82, 0.94, 1.04 Ga) and Early Riphean (peaks on relative probability plots – 1.38, 1.45, 1.64 Ga) ages predominate. The single grains have a Middle Riphean, Early Proterozoic and Late Archean ages. We can suppose, that the sources of Late Riphean detrital zircons from sandstones of the Chergilen and Allin formations are igneous rocks of gabbro-granitoids (940–933 Ma) and granite- leucogranites (804–789 Ma) association, identified in the Bureya continental Massif. We can`t assume, what kind of rocks were the source for Middle Riphean and older detrital zircons from the Cambrian sedimentary rocks of the Bureya continental Massif, because in this massif still do not identified complexes older Late Riphean age. The most probable geodynamic conditions of accumulation of the Cambrian deposits of the Mel’gin trough is the conditions of active continental margin, which is corresponding to of Early Cambrian granitoids magmatism.

scholarly journals Supplemental Material: Syn-exhumation magmatism in an active continental margin above a continental subduction zone: Evidence from Late Triassic mafic igneous rocks in the southeastern North China Block

2020 ◽  
Author(s):  
Wei Fang ◽  
Li-Qun Dai
Keyword(s):  
Trace Element ◽  
Subduction Zone ◽  
Continental Margin ◽  
North China ◽  
Active Continental Margin ◽  
Hf Isotope ◽  
Igneous Rocks ◽  
Late Triassic ◽  
North China Block ◽  
Pb Isotope

Table S1: Major and trace element compositions of mafic igneous rocks from the southeastern North China Block; Table S2: Whole-rock Rb-Sr, Sm-Nd, and Lu-Hf isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S3: LA-ICPMS zircon U-Pb isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S4: Zircon LA-MC-ICPMS Lu-Hf and SIMS O isotopic compositions of mafic igneous rocks from the southeastern North China Block.

Provenance of Late Ordovician sedimentary rocks in the SE Yangtze block: Implications for deposition in an active continental margin

2020 ◽  
Vol 127 ◽  
pp. 103862
Author(s):  
Tao Yu ◽  
Zongqi Wang ◽  
Dongsheng Wang ◽  
Changqian Ma ◽  
Yingli Zhang ◽  
...  
Keyword(s):  
Continental Margin ◽  
Active Continental Margin ◽  
Sedimentary Rocks ◽  
Late Ordovician ◽  
Yangtze Block

Age and source of detrital zircons from the Missi Formation: a Proterozoic molasse deposit, Trans-Hudson Orogen, Canada

1992 ◽  
Vol 29 (12) ◽  
pp. 2583-2594 ◽  
Author(s):  
Kevin M. Ansdell ◽  
T. Kurtis Kyser ◽  
Mel R. Stauffer ◽  
Garth Edwards
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Early Proterozoic ◽  
Minimum Age ◽  
Granitoid Rocks ◽  
Evaporation Technique ◽  
Single Zircon ◽  
Flin Flon ◽  
Felsic Volcanic

The Missi Formation in the Flin Flon Basin forms part of a discontinuous series of molasse-type sediments found throughout the Early Proterozoic Trans-Hudson Orogen in northern Saskatchewan and Manitoba. The Flin Flon Basin contains a sequence of proximal-fan to braided-stream fluvial conglomerates and sandstones, which unconformably overlie subaerially weathered Amisk Group volcanic rocks. Stratigraphic way-up indicators have been preserved, even though these rocks have undergone greenschist-facies metamorphism and polyphase deformation. The sedimentary rocks are crosscut by intrusive rocks, which provide a minimum age of sedimentation of 1840 ± 7 Ma.Detrital zircons from each of the six stratigraphic subdivisions of the Flin Flon Basin were analyzed using the single-zircon Pb-evaporation technique. Euhedral to slightly rounded zircons dominate each sample, and these zircons give ages of between about 1854 and 1950 Ma. The Missi sediments were thus deposited between 1840 and 1854 Ma. Possible sources for the detrital zircons are Amisk Group felsic volcanic rocks and post-Amisk granitoid rocks and orthogneisses in adjacent domains within the Trans-Hudson Orogen. However, the immature character of the sedimentary rocks, the composition of clasts, the euhedral character of many of the zircons, and the range in ages suggest that most were likely derived from Amisk Group and granitoid rocks in the western Flin Flon Domain. Rounded zircons are uncommon but provide evidence for the reworking of older Proterozoic sedimentary rocks, or a distant Archean or Early Proterozoic granitoid terrane.

A Reconstruction of a Vendian–Cambrian Active Continental Margin within the Southern Urals: Results of Detrital Zircons Studying from Ordovician Terrigenous Rocks

Geotectonics ◽  
2019 ◽  
Vol 53 (4) ◽  
pp. 485-499 ◽  
Author(s):  
A. V. Ryazantsev ◽  
N. B. Kuznetsov ◽  
K. E. Degtyarev ◽  
T. V. Romanyuk ◽  
T. Yu. Tolmacheva ◽  
...  
Keyword(s):  
Continental Margin ◽  
Active Continental Margin ◽  
Southern Urals ◽  
Detrital Zircons ◽  
The Southern Urals ◽  
Terrigenous Rocks

Reassessment of the Mesozoic metasedimentary rocks and tectonic setting of Taiwan and the adjacent continental margin of eastern Asia

2016 ◽  
Vol 154 (5) ◽  
pp. 1127-1154 ◽  
Author(s):  
YU WANG ◽  
CHIN-HO TSAI ◽  
LIYUN ZHOU ◽  
YAN QIU ◽  
GUIHUA SUN
Keyword(s):  
Continental Margin ◽  
Tectonic Setting ◽  
Active Continental Margin ◽  
Crystalline Basement ◽  
Detrital Zircons ◽  
Source Rocks ◽  
Metamorphic Belt ◽  
Late Mesozoic ◽  
Sedimentary Sequences ◽  
Se China

AbstractIt remains unclear whether a crystalline basement exists in SE China (including Taiwan), whether the formation of the Tananao metamorphic belt in Taiwan was linked to subduction of the Palaeo-Pacific Plate, and whether the source rocks of the sedimentary sequences in the metamorphic belts are late Mesozoic or Palaeozoic in age. Field investigations and zircon age data in the present study indicate that there is no pre-Palaeozoic gneiss (crystalline basement) in Taiwan (although orthogneisses were produced during deformation and metamorphism of Mesozoic granites), and investigations of the metasediments show that the sedimentary sequences in the Tailuko and Yuli belts are similar. Moreover, LA-ICP-MS dating of detrital zircons from the Pingtan–Dongshan belt in Fujian Province yields a cluster of 206Pb–238U ages at ~ 210–190 Ma, and the Tailuko and Yuli belts in Taiwan have similar clusters of detrital zircon ages at 200 Ma, 160 Ma, 120 Ma and 110 Ma, as well as a later overprinting caused by arc–continent collision. The cathodoluminescence images and trace-element characteristics of the zircons show that they were originally magmatic in origin. This finding, combined with the Hf isotope data, indicates that the sources of sediments in the Tananao belt (Tailuko and Yuli belts) were relatively close to an active continental margin, and that both the Tailuko and Yuli belts have similar sedimentary sources. From the margin of the Chinese mainland to Taiwan, the metasediments seem to represent a continuous sequence of deposits ranging in age from Jurassic to Cretaceous, but with the sediments becoming progressively younger towards the east. It can be inferred that the sediments in the Tailuko and Yuli belts were continental-shelf sequences with sources in SE China.

scholarly journals Supplemental Material: Syn-exhumation magmatism in an active continental margin above a continental subduction zone: Evidence from Late Triassic mafic igneous rocks in the southeastern North China Block

2020 ◽  
Author(s):  
Wei Fang ◽  
Li-Qun Dai
Keyword(s):  
Trace Element ◽  
Subduction Zone ◽  
Continental Margin ◽  
North China ◽  
Active Continental Margin ◽  
Hf Isotope ◽  
Igneous Rocks ◽  
Late Triassic ◽  
North China Block ◽  
Pb Isotope

Table S1: Major and trace element compositions of mafic igneous rocks from the southeastern North China Block; Table S2: Whole-rock Rb-Sr, Sm-Nd, and Lu-Hf isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S3: LA-ICPMS zircon U-Pb isotope compositions of mafic igneous rocks from the southeastern North China Block; Table S4: Zircon LA-MC-ICPMS Lu-Hf and SIMS O isotopic compositions of mafic igneous rocks from the southeastern North China Block.

Early-Paleozoic geodynamics of the Altai orogen: Constraints from geochemical and zircon U-Pb-Hf isotopic study of paragneissic rocks from the southern Chinese Altai

2020 ◽  
Author(s):  
Xing Cui ◽  
Min Sun ◽  
Guochun Zhao ◽  
Yunying Zhang ◽  
Jinlong Yao ◽  
...  
Keyword(s):  
Active Continental Margin ◽  
Detrital Zircons ◽  
Igneous Rocks ◽  
Cumulative Distribution ◽  
Geochemical Data ◽  
Accretionary Wedge ◽  
Early Paleozoic ◽  
Isotopic Study ◽  
Zircon Age ◽  
Southern Chinese

<p>The high-grade metamorphic complexes in the Chinese Altai were previously regarded as the Precambrian basement and thus important for unravelling tectonic evolution of the Altai orogen. This study reports detailed filed investigation, zircon U-Pb-Hf isotopic and whole-rock geochemical data for the paragneissic rocks from Northern Fuyun Complex (NFC), southern Chinese Altai. Detrital zircons from the paragneisses have a predominant early Paleozoic age population (ca. 535-435 Ma), with minor Neoproterozoic and sparse Mesoproterozoic to Archean ages. The geochemical analyses together with the euhedral shape of the detrital zircons suggest that their sedimentary protoliths mainly came from felsic-intermediate igneous rocks with low maturity. In combination with the cumulative distribution curves of zircon age spectra, the variable zircon εHf(t) values (-25 to +13), as well as the immature geochemical compositions, we infer that the protoliths were most likely deposited on an active continental margin in the early Paleozoic and sourced mainly from proximal igneous rocks, which are comparable to the Habahe Group. Similar detrital zircon age spectra of early Paleozoic sequences from the Chinese Altai, Mongolia Altai and Khovd Zone support the existence of a giant accretionary wedge developed along the western margin of the Ikh-Mongol Arc system, resulting from continuous northeast-dipping oceanic subduction. This research was financially supported by the National Key R&D Program of China (2017YFC0601205), Hong Kong RGC GRF (17302317 and 17303415) and NSFC Projects (41730213 and 41190075).</p>

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