scholarly journals Age and sources of the Lower Mesozoic metasedimentary rocks of the Un'ja-Bom terrane in the Mongol-Okhotsk fold belt: results of the U–Th–Pb geohronological (LA–ICP–MS) AND Sm–Nd isotope studies

2019 ◽  
Vol 484 (4) ◽  
pp. 455-459
Author(s):  
V. A. Zaika ◽  
A. A. Sorokin ◽  
V. P. Kovach ◽  
A. P. Sorokin ◽  
A. B. Kotov
Keyword(s):  
Sedimentary Rocks ◽  
Detrital Zircons ◽  
Fold Belt ◽  
Relative Probability ◽  
Nd Isotope ◽  
Metasedimentary Rocks ◽  
Icp Ms ◽  
Isotope Studies ◽  
Geochemical Studies ◽  
Age Estimates

The results of the U—Th—Pb geochronological studies indicate that in the Un’ja-Bom terrane the youngest peaks on the relative probability curves of ages are 207 and 212 Ma for zircons from the metasiltstone of the Kurnal formation and from the metasiltstone of the Amkan formation. Similar age estimates for the youngest peaks were obtained for the detrital zircons from the metasedimentary rocks of the Tukuringra terrain of the eastern part of the Mongol-Okhotsk belt, which indicates that the Lower Mesozoic flyschoid complexes in the structure of this belt are developed much wider than is currently believed. The results obtained in our U—Th—Pb geochronological and Sm—Nd isotope geochemical studies suggest’s that the sedimentary rocks material was carried to the sedimentation basin mainly from the continental massifs of the Amur superterrane.

scholarly journals Age and sources of the metasedimrntary rocks of the Tokur terrane in the Mongol-Okhotsk fold belt: results of the U–Pb geoсhronological and Lu–Hf isotope studies

2019 ◽  
Vol 486 (4) ◽  
pp. 446-450
Author(s):  
V. A. Zaika ◽  
A. A. Sorokin ◽  
A. P. Sorokin
Keyword(s):  
Detrital Zircons ◽  
Hf Isotope ◽  
Fold Belt ◽  
Metasedimentary Rocks ◽  
The North ◽  
Icp Ms ◽  
North Asia ◽  
Southeastern Margin ◽  
Isotope Studies ◽  
Metamorphic Complexes

This paper presents the results of U–Pb (LA–ICP–MS) and Lu–Hf ­isotope studies of detrital zircons from metasedimentary rocks of the Tokur Terrane. It has been shown that metasedimentary rocks of the Tokur and Ekimchan formations are characterized by similar age peaks of detrital zircons, which indicates a close (or same) age of these formations. The lower age of the sedimentation is determined by the age of the youngest zircons of 326–323 Ma. The upper age boundary is determined of 254–251 Ma, based on the intruded of the Late Permian granitoids. The main sources of zircons in the metasedimentary rocks of the Tokur Terrane are the igneous and metamorphic complexes of the southeast framing of the North Asia Craton. The Tokur Terrane can be considered as a fragment of the Paleozoic accretionary complex, the formation in front of the southeastern margin of the North Asia Craton.

scholarly journals The exotic inim block of the argun continental superterrane of the central asian fold belt: results of U-Th-pb geochronological (LA-ICP-MS) and Sm-Nd isotopic-geochemical studies

2019 ◽  
Vol 484 (6) ◽  
pp. 734-738
Author(s):  
R. O. Ovchinnikov ◽  
A. A. Sorokin ◽  
A. B. Kotov ◽  
E. B. Sal'nikova ◽  
V. P. Kovach ◽  
...  
Keyword(s):  
Continental Crust ◽  
Central Asian Fold Belt ◽  
Fold Belt ◽  
Early Precambrian ◽  
Metasedimentary Rocks ◽  
Tectonic Events ◽  
Central Asian ◽  
Icp Ms ◽  
Archean Crust ◽  
Geochemical Studies

The results of studies indicate that the age of the protoliths of garnet-bearing biotite–sericite–muscovite schists of the Inim Block is <991 Ma, and they are derived from rocks of the Neo-, Meso-, and Paleoproterozoic (as well as Archean) crust. This suggests that the Inim Block is exotic relatively to the Argun Superterrane due to the formation of the protolith of its metasedimentary rocks largely from erosion products of the Early Precambrian continental crust, the presence of which within the Argun Superterrane is not proven. It is not excluded that the Inim Block is a fragment of the Dzhugdzhur–Stanovoi Superterrane implanted in the structure of the Argun Superterrane as a result of Mesozoic tectonic events.

scholarly journals Age and formation features of the Ordovician Chalovskaya sequence in the Argun Massif, eastern part of the Central Asian fold belt

2019 ◽  
Vol 27 (3) ◽  
pp. 3-23
Author(s):  
Yu. N. Smirnova ◽  
A. A. Sorokin
Keyword(s):  
Active Continental Margin ◽  
Detrital Zircons ◽  
Central Asian Fold Belt ◽  
Early Paleozoic ◽  
Fold Belt ◽  
Late Precambrian ◽  
Central Asian ◽  
Icp Ms ◽  
Geochemical Studies ◽  
Metaterrigenous Rocks

In this paper we present the results of the mineralogical and geochemical studies of metaterrigenous rocks of the Grebnev and Magdagachi formations of the Chalovskaya Sequence – one of the key stratigraphic divisions of the Argun continental Massif in the eastern part of the Central Asian fold belt, and U–Pb geochronological (LA-ICP-MS) data for the detrital zircons from these rocks. It is established that the youngest zircons in the metasandstones of the Grebnev Formation have an age of ~478 Ma, and in the metaalevrolites of the Magdagachi Formation ~448 Ma. Together with the previously obtained data on the age of metadacites from the Isagachi Formation (476 ± 8 Ma), this information indicates the Ordovician age of the Chalovskaya Sequence, previously attributed to the Late Precambrian. It was shown that the accumulation of sediments of the Chalovskaya Sequence took place in an environment of an active continental margin or island arc simultaneously with intense magmatic activity. Taking into account the fact that the Early Paleozoic suprasubduction magmatism manifested within all the continental massifs of the eastern part of the Central Asian fold belt (Argun, Mamyn, Bureya, Jiamusi, Khanka), it cannot be excluded that the mentioned continental massifs have a common geodynamic history.

scholarly journals Sources and source areas of the Upper Paleozoic metasedimentary rocks of the Dzhagda terrane of the Mongol-Okhotsk fold belt: the results of Sm-Nd isotope geochemical studies

2018 ◽  
Vol 9 (4) ◽  
pp. 1331-1338 ◽  
Author(s):  
V. A. Zaika ◽  
A. A. Sorokin ◽  
V. P. Kovach
Keyword(s):  
Fold Belt ◽  
North Asian Craton ◽  
Nd Isotope ◽  
Source Areas ◽  
Metasedimentary Rocks ◽  
The North ◽  
Upper Paleozoic ◽  
Geochemical Studies ◽  
Nd Model Age ◽  
Metaterrigenous Rocks

The article presents the results of Sm-Nd isotope geochemical studies of the Upper Paleozoic metasedimentary rocks of the Dzheskogon, Nektera and Bochagor suites of the Dzhagda terrane. These rocks are characterized by slightly varying values of the Nd model age tNd(DM)=1.5–1.0 Gyr, which gives evidence that the main sources of protoliths were the rocks of the Mesoproterozoic Nd model age (in average). This Nd model age is similar to the ages of the metaterrigenous rocks of the Teply Klyuch, Garmakan and Alga suites of the Tukuringra terrane of the Mongol-Okhotsk Belt. The results obtained in our studies suggest that the sedimentary rocks of the Dzhagda and Tukuringra terranes developed from the material that was mainly sourced from the Amur superterrane (from the south in modern coordinates). A supply of the material from the southern margin of the North Asian craton (from the north in modern coordinates) was either absent or minimal.

scholarly journals AGE AND SOURCES OF PROTOLITHS OF METASEDIMENTARY ROCKS IN THE EASTERN TUKURINGRA TERRANE OF THE MONGOL-OKHOTSK FOLD BELT: RESULTS OF U-TH-PB, LU-HF, AND SM-ND ISOTOPE STUDIES

2021 ◽  
Vol 40 (3) ◽  
pp. 16-27
Author(s):  
V.A. Zaika ◽  
◽  
A.A. Sorokin ◽  
Keyword(s):  
Early Jurassic ◽  
Late Triassic ◽  
Fold Belt ◽  
North Asian Craton ◽  
Nd Isotope ◽  
Metasedimentary Rocks ◽  
Isotope Data ◽  
The North ◽  
Early Mesozoic ◽  
Isotope Studies

The article presents detrital zircon U-Th-Pb and Lu-Hf isotope data for metasedimentary rocks from the eastern Tukuringra Terrane, as well as whole-rock Sm-Nd isotope data. Our analyses show that the zircons in metasedimentary rocks are mostly early Mesozoic in age. Early Paleozoic and Neoproterozoic zircons are also common, whereas early Precambrian zircons are virtually absent. The age of the youngest zircon population places a lower age limit on the age of the Tungalin Formation at 204 Ma (Late Triassic, Rhaetian), the Dugda Formation at 181 Ma (Early Jurassic, Toarcian), and the Tangomen Formation at 189 Ma (Early Jurassic, Pliensbachian). Essentially all Mesozoic, Paleozoic and Neoproterozoic zircons are characterized by Neo- and Mesoproterozoic Hf-model ages (tHf(DM) = 1.41–0.46 Ga, tHf(C) = 1.55–0.49) and Mesoproterozoic Nd-model ages (tNd(DM) = 1.25–1.10 Ga, tNd(С) = 1.31–1.14). Our results suggest that sediments for deposition were sourced mainly from the continental Amuria Superterrane, but not from the southern margin of the North Asian Craton.

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.

The Exotic Inim Block of the Argun Superterrane of the Central Asian Fold Belt: Results of U–Th–Pb Geochronological (LA-ICP-MS) and Sm–Nd Isotopic–Geochemical Studies

2019 ◽  
Vol 484 (2) ◽  
pp. 151-155
Author(s):  
R. O. Ovchinnikov ◽  
A. A. Sorokin ◽  
A. B. Kotov ◽  
E. B. Sal’nikova ◽  
V. P. Kovach ◽  
...  
Keyword(s):  
Central Asian Fold Belt ◽  
Fold Belt ◽  
Central Asian ◽  
Icp Ms ◽  
Geochemical Studies
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