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1.
Qiu-Ming Pei Shou-Ting Zhang Ken-ichiro Hayashi Dong Li Li Tang 《International Geology Review》2018,60(9):1172-1194
The Xing’an–Mongolia orogenic belt is located in the southeastern segment of the Central Asian Orogenic Belt. Its tectonic evolution, especially during the Late Palaeozoic to Early Mesozoic, remains controversial. Here, we report new zircon U–Pb dates, whole-rock geochemistry, and Hf isotopes of representative samples from four plutons in the Linxi area of Northeast China to provide new constraints on this issue. Zircon U–Pb dating indicates that the intrusions were emplaced in two stages: (1) Late Permian to Early Triassic (the Banshifangzi and Xinangou plutons (252 ± 3)–(246.3 ± 3.3) Ma); and (2) Late Triassic (the Baoshan and Hada plutons (220.8 ± 2.7)–(211.4 ± 2.6) Ma). Their positive εHf(t) values (6.6–14.1), coupled with their geochemical characteristics, suggest that the provenance of investigated granitoids were most likely to be dominated by juvenile crustal materials. Based on these new data and previous studies, we propose three stages of tectonic evolution during the Late Palaeozoic–Early Mesozoic in the XMOB: (1) Late Carboniferous–Early Permian (330–270 Ma): double-sided subduction of the Palaeo-Asian Ocean; (2) Middle Permian–Middle Triassic (270–237 Ma): the closure of the Palaeo-Asian Ocean and subsequent continent–continent collision between the North China Craton and the South Mongolia Terrane; and (3) Late Triassic (237–211 Ma): post-collisional extension. 相似文献
2.
《地学前缘(英文版)》2020,11(4):1415-1429
As the southernmost segment of the Central Asian Orogenic Belt (CAOB), the northern Alxa orogenic belt (NAOB) connects the southeastern and southwestern segments of the CAOB. The NAOB amalgamated with the closure of the Paleo-Asian Ocean; however, the closure time of the Paleo-Asian Ocean is still on great debate. In this study, we reported new detrital zircon U–Pb geochronology and Hf–O isotopes for the Permo–Carboniferous sediments in the northern Alxa to constrain the provenance and its tectonic implications. The Permo–Carbonifereous Amushan Formation is composed of volcanic-carbonite-clastic rocks and was deposited in a shallow marine environment. Based on the zircon U–Pb geochronology, the Amushan Formation was deposited in the late Carboniferous to early Permian, but some outcrops of volcanic and clastic rocks in the Quaganqulu area were likely formed in the middle to late Permian. The integrated zircon age spectrum for the clastic rocks shows a wide range from late Archean to Paleoproterozoic, Mesoproterozoic (with a peak age at 1458 Ma), early Neoproterozoic (with peak ages of 988 Ma and 929 Ma), early Paleozoic (with a peak age at 447 Ma) and late Paleozoic (with a peak age at 294 Ma). Combined with the zircon Hf–O isotopes, the provenance was considered to be the Alxa Block, the Shalazhashan terrane and the Zhusileng–Hangwula block (and the southern Beishan orogenic belt). The multiple source regions to the south and north of the Paleo-Asian Ocean indicate the closure of this ocean before the late Carboniferous. The absence or small proportion of depositional age-approximated zircons in most samples makes their age spectra similar to extensional basins. Combined with the intra-plate volcanism, the deposits were considered to be formed in extensional settings. Accordingly, after the closure of the Paleo-Asian Ocean, the NAOB stepped into an extensional stage. 相似文献
3.
ABSTRACTThe Circum–Balkhash–Junggar area, including mostly Kazakhstan, NW China, Russia, Kyrgyzstan, Tajikistan, Uzbekistan, and Mongolia, occupies an important tectonic position of the Central Asian Orogenic Belt (CAOB) (Figure 1). Tectonically, this vast area records the complicated geodynamic processes, among which the most prominent stages are the formation of the U-shaped Kazakhstan Orocline and its interactions with adjacent Altai (Altay), Junggar (West Junggar, Junggar Basin, and East Junggar), and Tianshan orogenic collages in the Palaeozoic, bearing large-scale mineral deposits. The formation of the Late Palaeozoic mineral deposits is related to the tectonic evolution of the Devonian and Carboniferous–Permian volcano-magmatic arcs in the region. However, the link between the metallogeny and the evolution of the volcano-magmatic arcs is not well understood and existing geodynamic models have not explained satisfactorily the mechanism of the huge metallogenic belt. Therefore, this special issue focuses on the formation of the Late Palaeozoic porphyry Cu deposits and their link to the tectonic evolution of the Devonian and Carboniferous–Permian volcano-magmatic arcs with emphasis on comparative studies across the international borders. 相似文献
4.
5.
Doklady Earth Sciences - New results of U–Pb geochronological and geochemical studies of rocks that form two structurally different massifs in the Mamyn Terrane are presented here. It has... 相似文献
6.
Ji Zejia Zhang Zhicheng Chen Yan Li Ke Yang Jinfu Qian Xiaoyan 《International Journal of Earth Sciences》2018,107(6):2143-2161
International Journal of Earth Sciences - The southeastern part of the Central Asian Orogenic Belt (CAOB), which records the collision of the North China Block (NCB) with the South Mongolian... 相似文献
7.
Ovchinnikov R. O. Sorokin A. A. Kotov A. B. Sal’nikova E. B. Kovach V. P. Sorokin A. P. 《Doklady Earth Sciences》2019,484(2):151-155
Doklady Earth Sciences - 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... 相似文献
8.
A.A. Sorokin A.B. Kotov E.B. Sal’nikova N.M. Kudryashov I.V. Anisimova S.Z. Yakovleva A.M. Fedoseenko 《Russian Geology and Geophysics》2010,51(5):563-571
According to U–Pb dating, the granitoids of the Tyrma–Bureya complex in the northern Bureya–Jiamusi superterrane of the Central Asian fold belt are not of Paleozoic, as previously thought, but of Mesozoic age (Nizhnyaya Stoiba massif, 218 ± 2 Ma; Talakan and Ust’-Dikan massifs, 185 ± 1 Ma). They formed at the early stages of collision between the North Asian and Sino-Korean cratons and the intervening Amur superterrane. 相似文献
9.
The Laoshankou Fe–Cu–Au deposit is located at the northern margin of Junggar Terrane, Xinjiang, China. This deposit is hosted in Middle Devonian andesitic volcanic breccias, basalts, and conglomerate-bearing basaltic volcanic breccias of the Beitashan Formation. Veined and lenticular Fe–Cu–Au orebodies are spatially and temporally related to diorite porphyries in the ore district. Wall–rock alteration is dominated by skarn (epidote, chlorite, garnet, diopside, actinolite, and tremolite), with K–feldspar, carbonate, albite, sericite, and minor quartz. On the basis of field evidence and petrographic observations, three stages of mineralization can be distinguished: (1) a prograde skarn stage; (2) a retrograde stage associated with the development of Fe mineralization; and (3) a quartz–sulfide–carbonate stage associated with Cu–Au mineralization. Electron microprobe analysis shows that garnets and pyroxenes are andradite and diopside-dominated, respectively. Fluid inclusions in garnet yield homogenization temperatures (Th) of 205–588 °C, and salinities of 8.95–17.96 wt.% NaCl equiv. In comparison, fluid inclusions in epidote and calcite yield Th of 212–498 and 150–380 °C, and salinities of 7.02–27.04 and 13.4–18.47 wt.% NaCl equiv., respectively. Garnets yield values of 6.4‰ to 8.9‰ δ18Ofluid, whereas calcites yield values of − 2.4‰ and 4.2‰ δ18Ofluid, and − 0.9‰ to 2.4‰ δ13CPDB, indicating that the ore-forming fluids were dominantly magmatic fluids in the early stage and meteoric water in the late stage. The δ34S values of sulfides range from − 2.6‰ to 5.4‰, indicating that the sulfur in the deposit was probably derived from deep-seated magmas. The diorite porphyry yields LA–MC–ICP–MS zircon U–Pb age of 379.7 ± 3.0 Ma, whereas molybdenites give Re–Os weighted mean age of 383.2 ± 4.5 Ma (MSWD = 0.06). These ages suggest that the mineralization-related diorite porphyry was emplaced during the Late Devonian, coincident with the timing of mineralization within the Laoshankou Fe–Cu–Au deposit. The geological and geochemical evidence presented here suggest that the Laoshankou Fe–Cu–Au deposit is a skarn deposit. 相似文献
10.
The Tuva–Mongolian terrane of the Central Asian Orogenic Belt is a composite structure with a Vendian–Cambrian terrigenous–carbonate cover. The Sangilen block in the southern part of the belt is a smaller composite structure, in which tectono–stratigraphic complexes of different age that were produced under various conditions were amalgamated in the course of Early Paleozoic tectonic cycle. The P–T parameters of the Early Paleozoic metamorphism in the western part of the Sangilen block corresponded to the amphibolite facies. The gneisses of the Erzin Complex contain relict granulite-facies mineral assemblages. The granulites are dominated by metasediments typical of deep-water basins on passive continental margins. The only exception is granulites of the Lower Erzin tectonic nappe of the Chinchlig thrust system: these rocks are metatholeiites, tonalites, and trondhjemites, whose REE patterns are similar to those of MORB. The composition of these granulites and their high Sm/Nd ratios indicate that the rocks were derived from juvenile crust that had been formed in an environment of a mature island arc or backarc basin. It is reasonable to believe that these rocks are fragments of the Late Riphean basement of the Sangilen block. The average 206Pb/238U zircon age of the garnet–hypersthene granulites is 494 ± 11 Ma. With regard for the zircon age of the postmetamorphic granitoids, the granulite-facies metamorphism occurred within the age range of 505–495 Ma. The peak metamorphic temperature reached 910–950°C, and the pressure was 3–4 kbar, which corresponds to ultrahigh-temperature/low-pressure (UHT–LP) metamorphism. The garnet–hypersthene orthogranulites were formed at a temperature that decreased to ~850°C and pressure that increased to ~5.5?7 kbar. It can be hypothesized that the earlier UHT–LP granulites were produced at an elevated heat flux and were later (in the course of continuing collision) overlain by a relatively cold tectonic slab, and this leads to a certain temperature decrease and pressure increase. This relatively cold slab could consist of fragments of the Vendian elevated-pressure metamorphic belt whose development terminated at the Vendian–Cambrian boundary before the onset of the Early Paleozoic regional metamorphism. 相似文献
11.
Fossil capybaras were long regarded as composed of numerous taxa, each one endemic to a particular area, a scenario completely different from the one shown by the living species. The interpretation of the record according to new criteria of ontogenetic change has demonstrated that they are useful for biocorrelation because their members have short biochrons with wide geographic distribution. The levels with capybaras of each locality would represent a short lapse within the bearing lithostratigraphic units. In turn, they would also represent short intervals within the temporal extension proposed for each Stage/Age or SALMA. All the late Miocene–Pliocene records of capybaras were analyzed and a chronological scheme was built mainly for Argentina, where records are most abundant. Numerical ages and magnetostratigraphic studies contribute to correlate this scheme with the global time scale. The Chasicoan SALMA would be correlated with part of the Tortonian Stage/Age; the Huayquerian SALMA with the late Tortonian-Messinian, and it could even extend to the earliest Zanclean. The Montehermosan SALMA would be restricted to the Zanclean. The Chapadmalalan SALMA would be correlated with the late Zanclean-early Piacenzian. 相似文献
12.
In this paper we consider the results of geological interpretation of 3DV (Tommot–Skovorodino segment) and Tynda–Amurzet geophysical transects crosscutting the Aldan Shield and the Stanovoi Granite–Greenstone Domain of the Siberian Platform; the Selengino–Stanovoi, Mongolia–Okhotsk, and Gobi–Hinggang foldbelts; and the Argun and Mamyn microcontinents with a total extent of sections of about 1000 km and depth of about 40 km. The data of previous studies and follow-up electric conductivity information have been used. The data of geological mapping, subject studies, and insights into the deep-seated structure of the considered territory obtained with a complex of geophysical methods are discussed. It is shown that Mesozoic strike-slip and thrust faults play the leading role in the present-day structure of the territory and in control rifting and mantle diapirism. It is suggested that Californian-type metamorphic nuclei, which are of structure-forming significance for adjacent territories in the west, have also developed in the studied region. 相似文献
13.
S. D. Velikoslavinskii A. B. Kotov V. P. Kovach A. M. Larin A. A. Sorokin A. P. Sorokin E. V. Tolmacheva E. B. Salnikova K. L. Wang B. M. Jahn S. L. Cung 《Doklady Earth Sciences》2016,468(2):561-565
The Gilyui Complex includes sedimentary and volcanic rocks metamorphosed to amphibolite and epidote–amphibolite facies, which constitute blocks confined to the main structural sutures of the Dzhugdzhur–Stanovoi superterrane in the Central Asian fold belt. In recent stratigraphic scales, they are considered as being Neoarchean in age with Nd model age values of 1.5–3.0 Ga. The youngest detrital zircons from metamorphosed mudstone of the Gilyui Complex yield a date of 285 ± 4 Ma, which determines the lower age limit for the formation of its protolith. The age of crystallization of rhyolites from the Gilyui Complex is determined to be 231 ± 4 Ma. If the rhyolites form volcanic flow units or sills, the Gilyui Complex is approximately 230 Ma or 231 ± 4 to 285 ± 4 Ma old, respectively. 相似文献
14.
Pedro Castiñeiras Carlos Villaseca Luis Barbero Cristina Martín Romera 《International Journal of Earth Sciences》2008,97(1):35-50
U–Pb SHRIMP ages obtained in zircons from the Sotosalbos and Toledo anatectic complexes in Central Spain give new constraints
to the evolution of the inner part of the Hercynian Iberian belt. Pre-Hercynian ages in zircons from the Sotosalbos complex
(∼464 Ma) are well preserved and reveal that an age diversity of the Lower Paleozoic magmatism in the area exists, as previous
data on westernmost orthogneisses yield significant older ages. Zircon ages in the pelite-derived granites from the Toledo
complex also show an important Neoproterozoic age component which points to a metasedimentary protolith deposited maximally
560 Ma ago. Younger zircon populations in both complexes at ∼330 Ma in the Sotosalbos region and ∼317 Ma in the Toledo complex
indicate an important diachronism between the anatectic processes in both areas but also that these processes are mainly unrelated
to the generation of the later Hercynian granite batholith of Central Spain, which could be of deeper crustal derivation.
In addition, as migmatization occurred late in the metamorphic cycle, after peak conditions were attained, the age of anatexis
is younger than the age of the main Hercynian metamorphic event, which still is not well constrained.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
15.
Chusi Li Mingjie Zhang Piaoer Fu Zhuangzhi Qian Peiqing Hu Edward M. Ripley 《Mineralium Deposita》2012,47(1-2):51-67
The Permian Kalatongke Ni–Cu deposits in the Central Asian Orogenic Belt are among the most important Ni–Cu deposits in northern Xinjiang, western China. The deposits are hosted by three small mafic intrusions comprising mainly norite and diorite. Its tectonic context, petrogenesis, and ore genesis have been highly contested. In this paper, we present a new model involving slab window magmatism for the Kalatongke intrusions. The origin of the associated sulfide ores is explained in the context of this new model. Minor amounts of olivine in the intrusions have Fo contents varying between 71 and 81.5?mol%, which are similar to the predicted values for olivine crystallizing from coeval basalts in the region. Analytic modeling based on major element concentrations suggests that the parental magma of the Kalatongke intrusions and the coeval basalts represent fractionated liquids produced by ~15% of olivine crystallization from a primary magma, itself produced by 7–8% partial melting of depleted mantle peridotite. Positive ε Nd values (+4 to +10) and significant negative Nb anomalies for both intrusive and extrusive rocks can be explained by the mixing of magma derived from depleted mantle with 6–18% of a partial melt derived from the lower part of a juvenile arc crust with a composition similar to coeval A-type granites in the region, plus up to 10% contamination with the upper continental crust. Our model suggests that a slab window was created due to slab break-off during a transition from oceanic subduction to arc–arc or arc–continent collision in the region in the Early Permian. Decompression melting in the upwelling oceanic asthenosphere produced the primary magma. When this magma ascended to pond in the lower parts of a juvenile arc crust, it underwent olivine crystallization and at the same time triggered partial melting of the arc crust. Mixing between these two magmas followed by contamination with the upper crust after the magma ascended to higher crustal levels formed the parental magma of the Kalatongke intrusions. The parental magma of the Kalatongke intrusions was saturated with sulfide upon arrival primarily due to olivine fractional crystallization and selective assimilation of crustal sulfur. Sulfide mineralization in the Kalatongke intrusions can be explained by accumulation of immiscible sulfide droplets by flow differentiation, gravitational settling, and downward percolation which operated in different parts of the intrusions. Platinum-group element (PGE) depletion in the bulk sulfide ores of the Kalatongke deposits was due to depletion in the parental magma which in turn was likely due to depletion in the primary magma. PGE depletion in the primary magma can be explained by a relatively low degree of partial melting of the mantle and retention of coexisting sulfide liquid in the mantle. 相似文献
16.
A.N. Didenko A.S. Efimov P.A. Nelyubov A.S. Sal’nikov V.S. Starosel’tsev B.F. Shevchenko M.V. Goroshko V.A. Gur’yanov N.G. Zamozhnyaya 《Russian Geology and Geophysics》2013,54(10):1236-1249
An integrated geological and geophysical study was performed to investigate the region of junction of the eastern part of the Central Asian Fold Belt and the Siberian Platform in the Skovorodino–Tommot 3-DV reference profile line (52°–60° N, 122°–129° E), where the belt is separated from the Aldan–Stanovoi Shield of the Platform by a series of deep faults. The main results are as follows: Seismic, density, and geoelectric characteristics of rocks were obtained and used to determine (refine) the intracrustal boundaries of tectonic structures; large-block structure of the Earth’s crust, caused by mantle faults, and the difference between the layered structure of the crust for the shield and fold regions were established; and available paleomagnetic data were used to perform palinspastic reconstructions for 180 and 140 million years, the most productive metallogenic epoch in the region, coeval with collision processes at the closure of the Mongol-Okhotsk paleobasin. 相似文献
17.
Kanygina N. A. Tretyakov A. A. Degtyarev K. E. Kovach V. P. Plotkina J. V. Pang K.-N. Wang K.-L. Lee H.-Y. 《Geotectonics》2020,54(2):212-228
Geotectonics - Detrital zircons from quartzite–schist sequences of the Aktau–Mointy Massif (Central Kazakhstan), which occur in various structural positions relative to the Early... 相似文献
18.
19.
Bezrukova E. V. Reshetova S. A. Volchatova E. V. Kuzmin M. I. 《Doklady Earth Sciences》2022,506(1):687-692
Doklady Earth Sciences - The Central part of the Oka Plateau lying in the East Sayan Mountains is still a poorly studied area of southern Siberia as regards its paleogeography. This gap can be... 相似文献
20.
Daniela Rubatto Dieter Gebauer Mark Fanning 《Contributions to Mineralogy and Petrology》1998,132(3):269-287
The Zermatt–Saas-Fee ophiolites (ZSFO) are one of the best preserved slices of eclogitic oceanic crust in the Alpine chain.
They formed during the opening of the Mesozoic Tethys and underwent subduction to HP/UHP conditions during Alpine compression. A cathodoluminescence-based ion microprobe (SHRIMP) dating of different zircon domains
from metagabbros and oceanic metasediments was carried out to constrain the timing of formation and subduction of this ophiolite,
two fundamental questions in Alpine geodynamics. The formation of the ophiolitic sequence is constrained by the intrusion
ages of the Mellichen and the Allalin metagabbros (164.0 ± 2.7 Ma and 163.5 ± 1.8 Ma) obtained on magmatic zircon domains.
These data are in line with the maximum deposition age for Mn-rich metasediments which overlie the mafic rocks at Lago di
Cignana (161 ± 11 Ma) and at Sparrenflue (ca. 153–154 Ma). An Eocene age of 44.1 ± 0.7 Ma was obtained for whole zircons and zircon rims from an UHP eclogite and two metasediments at Lago di Cignana. One of the Eocene zircons contains a rutile inclusion indicating formation
at HP conditions. As the temperature and pressure peak of these rocks nearly coincide, the Eocene zircons probably constrain the
age for the deepest subduction of the ZSFO. This Eocene age for the UHP metamorphism implies that the ZSFO were subducted later than the Adriatic margin (Sesia-Lanzo Zone) and before the Late Eocene
subduction of the European continental crust below Apulia. A scenario with three subduction episodes propagating in time from
SE to NW is proposed for the geological evolution of the Central and Western Alps.
Received: 1 December 1997 / Accepted: 8 April 1998 相似文献