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11.
We report a new paleomagnetic determination of Paleoproterozoic rocks from the Siberian craton which showed a positive baked contact test and a stable age of the high-temperature NRM component. The mean paleomagnetic pole of Siberia for ～1730 Ma located at 42.9° S, 109.6° E (α95 = 5.3°) is compatible with the pole positions obtained recently for the middle and late Early Proterozoic. 相似文献
12.
A. N. Didenko V. A. Gur’yanov A. Yu. Peskov A. N. Perestoronin D. V. Avdeev E. V. Bibikova T. I. Kirnozova M. M. Fugzan 《Russian Journal of Pacific Geology》2010,4(5):398-417
A model of the formation of the Ulkan trough was specified on the basis of new geochemical and geochronological data. The
volcanics of the Ulkan Group exhibit geochemical features typical of the rocks of two modern geodynamic settings: suprasubduction
and within-plate ones. The combination of the components derived from the different-depth sources in the magmatic chambers
explains the formation of the volcanics with mixed geochemical signatures. The age of the granitoids of three phases of the
Ulkan Massif is determined within the range of 1730–1925 Ga. The granites of the first and third phases have positive ɛNd(T)
of + 3.5 and + 0.7, respectively. The granites of the first phase of the Ulkan Complex were likely derived from the Paleoproterozoic
juvenile crust with an age of 1.84–1.95 Ga. The effusive rocks of the Ulkan Group were presumably formed in a geodynamic setting
of a Cordilleran-type transform continental margin. Judging from the model TNd(DM) age, these geodynamic conditions operated >1.84 Ga ago. 相似文献
13.
I. K. Kozakov A. N. Didenko P. Ya. Azimov T. I. Kirnozova E. B. Sal’nikova I. V. Anisimova Ch. Erdenejargal 《Geotectonics》2011,45(3):174-194
The Hercynian mobile belts in Central Asia comprise the Hercynian proper and the Late Hercynian (Indosinian) belts separated
by the South Gobi microcontinent, the origin of which is related to the evolution of the South Mongolian and Inner Mongolian
basins with the oceanic crust. Crystalline complexes within these belts occur as tectonic sheets of a variety of sizes. At
the early stages, the metamorphic grade of these complexes reached conditions of high-temperature subfacies of amphibolite
and locally developed granulite facies. In tectonic terms, the Hercynian belt of metamorphic rocks is situated at the margin
of the North Asian Caledonian continent and extends from the southeast to the northwest along the southern slope of the Gobi,
Mongolian, and Chinese Altai to East Kazakhstan, where metamorphic rocks are localized in the Irtysh Shear Zone. All these
rocks are combined into the South Altai metamorphic belt of more than 1500 km in extent. Another belt of isolated outcrops
of crystalline rocks conventionally combined into the Indosinian South Gobi metamorphic belt is traced along the junction
of the Hercynides with the South Gobi microcontinent. The high-grade metamorphic rocks within both belts are not fragments
of an ensialic Caledonian or older basement. These rocks were formed 390–360 and 230–220 Ma ago as a result of the closure
of the Tethian South Mongolian and Inner Mongolian oceanic basins (Paleotethys I and Paleotethys II). The spatial position
of the South Altai and South Gobi metamorphic belts is caused by the asymmetric structure of the Tethian basins, where active
continental margins are expressed most distinctly along their northern parts, while passive margins extend along the southern
parts (in present-day coordinates). 相似文献
14.
A. N. Didenko V. S. Zakharov G. Z. Gil’manova T. V. Merkulova M. V. Arkhipov 《Russian Journal of Pacific Geology》2017,11(2):123-133
The fractal dimension of the epicentral field of earthquakes (D = 1.6) is determined for the Sikote Alin orogen and adjacent areas. According to this parameter, the region occupies the position between the Kamchatka Peninsula, Kuril Islands (1.61 and 1.69), the East China area, and the Lake Baikal region (1.55 and 1.40). Differentiation of the studied area based on the fractal dimension of the number of earthquakes and on the released energy calculated per unit square shows that the most active crustal areas are associated with the Kharpi–Kur–Priamur’e zone of the northeastern orientation, which is the northern segment of the Tan-Lu transregional fault system. Analysis of the time series of seismic events (MLH ≥ 2.4) in the Sikhote Alin and adjacent areas in the period from 1960 to 2013 shows that the “harmonic” with a 10.5-year period is most clearly displayed. This period (11–13 years) was previously distinguished by B.V. Levin and coauthors from the study of the largest number of earthquakes with M ≥ 4.4 for the period of 1971–2003. 相似文献
15.
Didenko A. N. Nosyrev M. Yu. Shevchenko B. F. Gilmanova G. Z. 《Doklady Earth Sciences》2017,477(1):1368-1372
Doklady Earth Sciences - The depth of the base of the magnetoactive layer and the geothermal gradient in the Sikhote Alin crust are estimated based on a method determining the Curie depth point of... 相似文献
16.
A. N. Didenko S. Otoh V. V. Golozubov M. V. Arkhipov A. V. Kudymov A. Yu. Peskov M. Nagata K. Yamamoto 《Doklady Earth Sciences》2018,481(2):1000-1003
New results of dating of detrital zircons from the Kema and Silasa Formations (Albian, Sikhote–Alin Orogenic Belt) permit determination of the provenance sources and geodynamic settings of sediment deposition. The Silasa Formation was deposited in outer island arc settings, separated by a forearc basin from the inner island arc, where the Kema Formation sediments were accumulated. The significant depth and width of the forearc basin hindered input of continent-derived debris to the area of sedimentation of the Silasa Formation. 相似文献
17.
V. G. Nevstruyev N. V. Berdnikov A. N. Didenko B. G. Saksin N. A. Lavrik 《Doklady Earth Sciences》2018,482(1):1203-1206
A genetic relationship is shown for the noble-metal mineralization (up to 11.3 g/t of Pt and platinoids and 2.58 g/t of Au) discovered in the Poperechnoe Fe–Mn deposit and the fluid–explosive breccias. The composition of platinoid minerals is in agreement with the characteristics of ore and placer formations of the Ural–Alaskan type and corresponds to the isoferroplatinum–osmium igneous paragenesis. The noble metals were crystallized at the conditions that should take place at the crust–mantle boundary under partial melting of the slab rocks. The near-surface occurrence of these metals is caused by the rising of high-mobile fluid flows. The data obtained testify to the expedience of searches for noble metals associated with occurrences of fluidolites. 相似文献
18.
A. N. Didenko A. Yu. Peskov A. V. Kudymov I. P. Voinova A. I. Tikhomirova M. V. Arkhipov 《Izvestiya Physics of the Solid Earth》2017,53(5):733-749
The results of the paleomagnetic investigation of the sediments pertaining to the Silasinskaya Formation of the Kiselevka–Manoma terrane within the Sikhote Alin orogenic belt are presented. The ancient prefolding magnetization component is revealed: Decs = 271.7°, Incs = 52.2°, Ks = 13.5, and a 95s = 5.1° (positive fold and reversal tests); and the coordinates of the corresponding paleomagnetic pole for ~103 ± 10 Ma are calculated: Plat = 26.3°, Plong = 70.5°, dp = 4.8°, and dm = 7.0°. As a result of this study, the geodynamical settings and paleolatitudes of the formation of three objects in the northern part of Sikhote Alin orogen are established: (a) the Kiselevskaya Formation of the Kiselevka–Manoma terrane was formed 133 Ma ago at 19° N under the seamount condition on the Izanagi Plate; (b) the Silasinskaya Formation of the Kiselevka–Manoma terrane was formed 103 Ma ago at 35° N under the oceanic island arc conditions; and (c) the Utitskaya Formation of the Zhuravlevsk–Amur terrane was formed 95 Ma ago at 54° N in the active continental margin conditions. It is found that the transform continental margin of Eurasia developed in the time interval from 105 to 65 Ma ago in the regime of a left-lateral submeridional shear from 30° to 60° N. The complete attachment of the studied rocks of the Kiselevka–Manoma terrane to the Eurasia’s margin (to the Zhuravlevsk–Amur terrane) occurred at the boundary of 60–70 Ma. Simultaneously, the sense of the displacement in the submeridional shears changed from left-lateral to right-lateral with the formation of pullapart type basins (Lake Udyl’). 相似文献
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20.
The main stages of the evolution of newly formed structural elements are considered against the background of breakup of the
epi-Grenville Rodinia supercontinent, which started about 950 Ma ago. The paleomagnetic data on pathways of the traveling
of Rodinia’s fragments are analyzed and evidence for their geology, magmatism, and sedimentation are integrated with special
emphasis on the evolution of the continental margins. A series of paleotectonic maps with elements of paleogeography for time
intervals of 950–900, 850–800, 750–700, 650–630, and 570–550 Ma ago has been compiled on the basis of palinspastic reconstructions
with allowance for new paleomagnetic data primarily concerning the position of Siberia in the Late Precambrian. Objects all
over the world, not only in Russia, are involved in the analysis, though with less thoroughly described paleogeography. The
structural elements of the Paleoasian ocean are included into the system of global paleooceans and framing paleocontinents.
The history of the Paleoasian ocean is traced through 400 Ma from the breakup of the Rodinia supercontinent to the origin
of the new Paleogondwana supercontinent about 550 Ma ago. 相似文献