A Gravity-Derived Moho Model for the Sikhote Alin Orogenic Belt

2021 ◽  
Author(s):  
Alexei N. Didenko ◽  
Mikhail Yu. Nosyrev ◽  
Gul’shat Z. Gil’manova
Keyword(s):  
Orogenic Belt ◽  
Sikhote Alin

Late Cretaceous granitoids of the Sikhote–Alin orogenic belt, southeastern Russia: implications for the Mesozoic geodynamic history of the eastern Asian continental margin

2021 ◽  
pp. jgs2021-109
Author(s):  
Igor V. Kemkin ◽  
Andrei V. Grebennikov ◽  
Xing-Hua Ma ◽  
Ke-Ke Sun
Keyword(s):  
Late Cretaceous ◽  
Pacific Plate ◽  
Orogenic Belt ◽  
Sikhote Alin ◽  
Asian Continent ◽  
Content Type ◽  
Eastern Margin ◽  
Continental Plate ◽  
Supplementary Material ◽  
Cretaceous Magmatism

We present new U–Pb age data for granitoids in the Central Sikhote–Alin orogenic belt in SE Russia, which refute the established opinion about the absence of the Late Cretaceous magmatism at the eastern margin of the Paleo-Asian continent. It was previously thought that a period of magmatic quiescence occurred from 88 to 50 Ma, related to subduction of the Paleo-Pacific Plate under the eastern margin of the Paleo-Asian continent, although this is inconsistent with evidence from the Sikhote–Alin, Sakhalin, and Japan regions. Three suites of plutonic rocks with different ages were identified in this study. The first suite has ages of 105–92 Ma and formed in a syn-orogenic setting. The second (86–83 Ma) and third (ca. 73 Ma) suites formed during the post-orogenic stage of the Sikhote–Alin orogenic belt. The second and third suites were coeval with Late Cretaceous granitoids that formed in a suprasubduction continental arc known as the Eastern Sikhote–Alin volcanic–plutonic belt (ESAVPB). However, the studied rocks are located far inland from the ESAVPB. The ages of the studied granitoids coincide with the timing of a change in the angle of convergence between the Paleo-Pacific Plate and eastern margin of the Paleo-Asian continent. This change in motion of the oceanic plate with respect to the continental plate was probably caused by a rupture in the subducted slab (i.e., a slab tear), followed by asthenospheric upwelling and partial melting of the overlying crust, which ultimately generated post-orogenic intrusive magmatism.Supplementary material:https://doi.org/10.6084/m9.figshare.c.5738616

scholarly journals Окислительно-восстановительный фон в земной коре Сихотэ-Алиньского орогенного пояса при кристаллизации магматитов мел-палеогенового возраста: связь с геодинамикой

2020 ◽  
pp. 24-38
Author(s):  
Yu. V. Taltykin ◽  
◽  
L. F. Mishin ◽  
E. A. Konovalova ◽  
◽  
...  
Keyword(s):  
Orogenic Belt ◽  
Redox Conditions ◽  
Western Pacific ◽  
Sikhote Alin ◽  
Mechanism Of Formation ◽  
Magma Crystallization ◽  
The Relationship

A new mechanism for the formation of ilmenite and magnetite series of granitoids in the Sikhote-Alin orogenic belt is proposed. The existing distribution zones of these magmatites are associated with the regional redox background, where magma crystallization occurs. The paper shows the relationship between the redox background in the lithosphere of the region and subduction processes in the Cretaceous-Paleogene time. The proposed mechanism of formation of the ilmenite and magnetite zones of Sikhote-Alin also explains the differences in redox conditions during the crystallization of Mesozoic magmatites in the orogens of the Eastern and Western Pacific coasts.

scholarly journals CHARACTERISTICS OF SELF‐SIMILARITY OF SEISMICITY AND THE FAULT NETWORK OF THE SIKHOTE ALIN OROGENIC BELT AND THE ADJACENT AREAS

2019 ◽  
Vol 10 (2) ◽  
pp. 541-559
Author(s):  
V. S. Zakharov ◽  
A. N. Didenko ◽  
G. Z. Gil’manova ◽  
T. V. Merkulova
Keyword(s):  
Fractal Dimension ◽  
Quantitative Characteristic ◽  
Recurrence Plot ◽  
Orogenic Belt ◽  
Sikhote Alin ◽  
Self Similarity ◽  
Crustal Earthquakes ◽  
Self Similar ◽  
Fault Network ◽  
Bureya Massif

We performed a comprehensive analysis of the characteristics of self‐similarity of seismicity and the fault network within the Sikhote Alin orogenic belt and the adjacent areas. It has been established that the main features of seismicity are controlled by the crustal earthquakes. Differentiation of the study area according to the density of earthquake epicenters and the fractal dimension of the epicentral field of earthquakes (De) shows that the most active crustal areas are linked to the Kharpi‐Kur‐Priamurye zone, the northern Bureya massif and the Mongol‐Okhotsk folded system. The analysis of the earthquake recurrence plot slope values reveals that the highest b‐values correlate with the areas of the highest seismic activity of the northern part of the Bureya massif and, to a less extent, of the Mongol‐Okhotsk folded system. The increased fractal dimension values for the fault network (Df) correlate with the folded systems (Sikhote Alin and Mongol‐Okhotsk), while the decreased values conform to the depressions and troughs (Middle Amur, Uda and Torom). A comparison of the fractal analysis results for the fault network with the recent stress‐strain data gives evidence of their general confineness to the contemporary areas of intense compression. The correspondence between the field of the parameter b‐value for the upper crustal earthquakes and the fractal dimension value for the fault network (Df) suggests a general consistency between the self‐similar earthquake magnitude (energy) distribution and the fractal distribution of the fault sizes. The analysis results demonstrate that the selfsimilarity parameters provide an important quantitative characteristic in seismotectonics and can be used for the neotectonic and geodynamic analyses.

Neotectonic vertical movements of the South Sikhote-Alin and characteristics of self-similarity of the stream network

2020 ◽  
pp. 25-36
Author(s):  
D. A. Simonov ◽  
V. S. Zakharov ◽  
G. Z. Gilmanova ◽  
A. N. Didenko
Keyword(s):  
Fractal Analysis ◽  
Orogenic Belt ◽  
Complex Parameter ◽  
Sikhote Alin ◽  
The South ◽  
Self Similarity ◽  
Stream Network ◽  
Vertical Movements ◽  
Stage Of Development ◽  
Network Pattern

Morphostructural analysis of the relief and fractal analysis of the stream network of the South of the Sikhote-Alin orogenic belt were carried out. The formation of the relief at the neotectonic stage occurred in several stages, which was reflected in the stream network pattern: 1) during pre-Oligocene time there was a general uplift of Sikhote-Alin; 2) in the Pliocene there was an activation of vertical neotectonic movements, most intense to the East of the Central Sikhote-Alin fault and synchronous whith basalt volcanism; 3) in the Pleistocene vertical movements of significant amplitude did not occur, at this time the modern erosion-denudation relief of the region was formed; 4) at the end of the Pleistocene and in Holocene there was a slight activation of vertical movements to the East of the Central Sikhote-Alin fault, which was reflected in the peculiarities of residual relief. Comparison of morphological and fractal analysis results showed, that the maximum of complex parameter of self-similarity PRNS coincide with the areas of greatest increments in elevation and the minima is the smallest increment of relief or whith the areas whith most significant erosion. In regions with the stage character of neotectonic development during fractal analysis of stream network it is necessary to consider additional factors due to the peculiarities of development of the stream network at each stage of development, and conservative of its pattern, reflecting features of the development of the relief in different stages.

Crust-mantle systems of magmatic complexes of Sikhote-Alin' (Far East, Russia)

2020 ◽  
Author(s):  
Nina Gorelikova ◽  
Nikolay Bortnikov ◽  
Aleksandr Khanchuk ◽  
Valeriy Gonevchuk ◽  
Irina Chizhova ◽  
...  
Keyword(s):  
Melt Inclusions ◽  
Regional Distribution ◽  
Crustal Contamination ◽  
Orogenic Belt ◽  
Geochemical Data ◽  
High Water Content ◽  
Crustal Material ◽  
Sikhote Alin ◽  
Margin Setting ◽  
Transform Margin

<p>Geochemical, isotope-geochemical, geochronolochical and thermobarometric study showed that the Badzhal, Mayo-Chan and Kavalerovo zones from Sikhote-Alin-Northern Sakhalin orogenic belt comprise: (1) oldest and geochemically and isotopically distinctive alkali mafic rocks, whose formation was related to mantle (asthenospheric) diapir. The possible regional distribution of the diapir is likely marked by subalkaline rocks (monzonites) having mantle Sr (0,7050) and Nd (0,5125) isotopic compositions at the Central (Tigrinoe deposit) and Southern (Kavalerovo district) Sikhote-Alin; (2) Tin-bearing ore-magmatic systems of the studied zones at the “ore region” level have similar intricate multi-root structure of generation area. 3) Magmatic evolution accompanying by increasing ore-bearing potential results in the final appearance of Li-F granites in the Badzhal Complex, and tourmaline granites in the Silinka Complex of the Myao-chan zone (Gonevchuk, 2002).</p><p>The elevated F and Cl contents and high water content as parameters responsible for ore potential of melt were confirmed by thermobarometric data (Bortnikov et al, 2019). Some associations of fluid and melt inclusions indicate that magma crystallization was accompanied by degassing with exsolution of water-rich fluids, which is required to form ore bodies in OMS. These data confirm significant role of mantle in the formation of the Myao-Chan and Badzhal zones, as well as early cassiterite—stannite—sulfide stage of the Arsen’evskoe deposit of the Kavalerovo district.</p><p>Numerical simulation of granitoids of the studied zones performed using logical-information method by I.A. Chizhova (2010) confirms crustal-mantle nature of magmatic complexes formed under transform continental margin and subduction settings. These systems are characterized by different geochemical features, in particular, different proportions of high-field strength (Sc, Y, Zr, Hf, Pb, U, Th, Nb), REE, and siderophile (Co, Ni, Cr, V, Cu) elements.</p><p>Obtained results in combination with previous data indicate that the Badzhal, Myao-Chain, and Kavalerovo zones were formed through several episodes of the growth and reworking of the Sikhote Alin’ Mesozoic continental crust, which were triggered by underplating. Granitoids and genetically related tin—base metal deposits were formed at final stage. The revealed difference in Sr-Nd composition of the granitoids could be caused by both initial geochemical crustal heterogeneity and the different degree of crustal contamination.</p><p>Geochemical and isotopic characteristics of the studied granitoids show that they were mainly derived through melting of juvenile metamafic crust, with subordinate contribution of metasedimentary rocks.</p><p>The ore-bearing magmatic complexes were formed during a change of transform margin setting by accretion of Early Cretaceous terranes of the Sikhote Alin—North Sakhalin orogenic belt.</p><p>Observed petrogeochemical diversirty of the granitoids from different zones could be caused by variations of sedimentary material, as well as by contamination of magmas by upper crustal material during emplacement, different contribution of mantle source, and diverse mechanisms of mantle-crustal interaction (Khanchuk et al, 2019). </p><p>Obtained petrochemical, geochemical, and isotopic-geochemical data on the granitoids from the studied zones provide better understanding of diversity of tin-bearing magmatism and conditions of magma generation and evolution in transform margin setting at the continent-ocean boundary.</p><p> </p>

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