首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 26 毫秒
1.
The presence of zircons of crustal origin in the dunites of Kytlym, a subduction-related concentrically zoned dunite–clinopyroxenite–gabbro massif of the Urals Platinum-Bearing Belt, may provide the first direct evidence of the recycling of continental crust into the mantle. Zircons were part of subducted sediments that melted to produce silicic magmas with entrained restitic zircons. These melts induced partial melting in the overlying mantle, which later crystallized as the Kytlym massif. Zircons rapidly captured into early formed dunites were prevented from dissolving completely and underwent different degrees of recrystallization. A few crystals still record their original ages, which range from ∼410 Myr to ∼2800 Myr, thus revealing a different origin. The majority, however, recrystallized in the presence of a limited amount of melt and record the diapir formation, 350–370 Ma, which was coeval with the Uralian high-pressure metamorphism. Lastly, several grains record an age of ∼330 Myr, which is identical, within error, to the Rb–Sr age of the tilaitic gabbros, (337 ± 22 Myr), and may, therefore, represent the crystallization age of the last melts formed during the evolution of Kytlym.  相似文献   

2.
SHRIMP U–Pb data from two samples of foliated anatectic leucogneiss bracket the high-grade metamorphic history of metasediments from southern Prydz Bay, East Antarctica. Magmatic zircons in these two samples have mean crystallization ages of 535 ± 13 and 536 ± 35 Myr, and provide a good estimate for the timing of peak metamorphism and partial melting. Low-Th monazite grains in the same samples have mean ages of 528 ± 4 and 527 ± 11 Myr, which are within error of the zircon ages but may reflect a lower blocking temperature. High-Th monazite rims with younger mean ages of 518 ± 3 and 512 ± 13 Myr occur around low-Th cores in both samples, and were precipitated from hydrous fluids released during the crystallization of residual melts. These magmatic fluids were channelled along the retrograde foliation present in both samples. All mineral assemblages and fabrics preserved in the metasediments reflect intense Pan-African metamorphism and deformation, associated with high degrees of partial melting and significant vertical displacements of the crust. Continental reconstructions assuming limited Pan-African tectonism in East Antarctica should be reassessed in the light of these new data.  相似文献   

3.
A U–Pb zircon age of 91.2 ± 0.2 Myr from western India (St. Mary islands) confidently links India with the Late Cretaceous magmatic province in Madagascar (≈ 84–92 Ma), and the U–Pb age is within analytical error of the U–Pb age of the Analalava gabbro pluton (91.6 ± 0.3 Myr) in northeastern Madagascar. Palaeomagnetic data from India and Madagascar allow us to postulate a new India–Madagascar fit (Euler latitude = 14.24°, longitude = 38.8° and rotation angle = –69.2°). This fit is applicable to the Late Cretaceous, directly prior to and during the early phase of Madagascar–India separation. In our Late Cretaceous reconstruction, south-west India runs roughly subparallel with the first known break-up related magnetic anomaly (A34); it maintains a close connection between Mada-gascar and India, but places India slightly rotated compared to the eastern margin of Madagascar and more northerly compared with some reconstructions. St. Mary magmatism is linked to the initial break-up between India and Madagascar, and magmatism probably resulted from rift-related extensional processes initially induced by the Marion hotspot underlying southern Madagascar during the Late Cretaceous.  相似文献   

4.
早白垩世岩浆活动对辽东半岛五龙地区金矿形成可能具有明显的制约作用,并可能为含金流体提供了热源及动力.五龙金矿南、北早白垩世三股流岩体和五龙背岩体角闪石-斜长石温压计计算结果表明,这2个岩体角闪石结晶温度为640.8~757.4 ℃,对应岩浆的侵位深度为5.9~9.7 km.角闪石TiO2-Al2O3图解表明,三股流和五龙背岩体岩浆源区为壳幔混源.三股流和五龙背岩体侵位深度的差异表明,晚白垩世晚期至早始新世和晚始新世至渐新世五龙地区发生的两期强烈的差异性隆升和剥露过程使五龙岩体、三股流岩体及五龙背岩体在研究区大面积出露,含金矿脉随着区域性隆升到达近地表.考虑到辽东半岛与胶东半岛的相似构造背景,认为五龙地区具有进一步金矿勘探的价值.   相似文献   

5.
This study provides new constraints on fast cooling and exhumation rates of high-pressure metamorphic rocks in young active mountain belts. Ion microprobe (SHRIMP) U–Pb analysis of zircon in a pyroxenite layer of the Cerro del Almirez ultramafic rocks (Nevado-Filábride Complex, southern Spain) gave an age of 15.0 ± 0.6 Myr (95% c.l.). Mineral inclusions demonstrate that zircon formed close to the high-pressure peak. Combined with previous fission track data, the 15 Myr age suggests high cooling (˜ 80 °C Myr−1) and exhumation (˜1.2 cm yr−1) rates for the unit. The new results indicate that both the Nevado-Filábride Complex and the overlying Alpujárride Complex, with somewhat higher ages and exhumation rates, underwent similar metamorphic evolutions at different times. This implies that the Alpujárride rocks were exhumed when the Nevado-Filábride was subducting and that the same tectonic scenario propagated from one portion of the Betic Cordilleras to another.  相似文献   

6.
Early Paleozoic granitoids of autochthonous and allochthonous facies in the Baikal area (Ol’khon Island, Khamar-Daban Ridge) are in close spatial association with gneisses, migmatites, and plagiogranites and are usually confined to granite–gneiss domes. They are virtually not subjected to magmatic differentiation. Formation of granitoids of the Solzan massif and Sharanur complex lasted 26–28 Myr, which might be considered an indicator of collisional granitoid magmatism. Collisional granitoids of different provinces have a series of indicative features: They are peraluminous and highly potassic and are enriched in crustal elements (Rb, Pb, and Th) but sometimes have low contents of volatiles. In contrast to collisional magmatism, petrogenesis of intraplate granitoids does not depend on the composition and age of the enclosing rocks. The geochemical evolution of intraplate granitoid magmatism in the Baikal area is expressed as an increase in contents of F, Li, Rb, Cs, Sn, Be, Ta, Zr, and Pb and a decrease in contents of Ba, Sr, Zn, Th, and U during the differentiation of multiphase intrusions. The geochemical diversity of these granitoids formed both from crustal and from mantle sources and as a result of the mantle–crust interaction, might be due to the effect of plume on the geologic evolution of intraplate magmatism. The wide range of compositions and geochemical types of igneous rocks (from alkali and subalkalic to rare-metal granitoids) within the Late Paleozoic Baikal magmatism area suggests its high ore potential.  相似文献   

7.
We provide new geological and isotope geochemical constraints on the evolution from continental rifting to sea-floor spreading along a segment of the Jurassic Tethyan margin exposed in the Platta and Err nappes (eastern Central Alps). Field observations show that the ocean–continent transition zone is characterized by oceanward-dipping detachment faults leading to the exhumation of subcontinental mantle rocks subsequently intruded by gabbro bodies and dolerite dikes, and covered by pillow basalts and radiolarites. Zircons extracted from gabbros and albitite yield concordant U–Pb ages of 161 ± 1 Ma; their initial ɛHf (+ 14.4 to + 14.9) as well as bulk rock ɛNd values of from gabbros and basalts (+ 7.3 to + 9.5) point to a MORB-type depleted mantle source. These data suggest that the onset of magmatic activity coincides with the latest phase of mantle exhumation along low-angle detachment faults and may be controlled by upwelling asthenosphere beneath a zone of exhumed continental mantle.  相似文献   

8.
Bosch  & Bruguier 《地学学报》1998,10(5):274-279
U–Pb zircon data from a felsic gneiss located at the contact zone with the central peridotite body of Zabargad Island (Red Sea, Egypt) provide an age of 23.2 ± 5.9 Myr consistent with the 238U–206Pb age of the youngest concordant grain (22.4 ± 1.3 Myr). Concordant grains indicate new zircon growth and/or resetting whereas slightly discordant analyses suggest participation of an older zircon component whose age cannot be defined precisely. SEM back-scattered imaging further reveals the occurrence of zoned domains almost completely erased by complex internal structures attributed to extensive recrystallization under metamorphic conditions. The 22.4 Myr Miocene age is thus interpreted as dating a high-temperature metamorphic event. The proximity between the studied sample and the peridotite supports previous conclusions which regard parts of the peridotites from Zabargad Island as an asthenopheric mantle diapir which intruded the thinned Pan-African continental crust during the early stages of the Red Sea opening.  相似文献   

9.
Some granites, granitoid dykes and volcanic rocks of the Southern Black Forest were dated by U–Pb techniques using zircon and monazite. An effusive rhyolite, which is interbedded in upper Visean sedimentary sequences of the Badenweiler-Lenzkirch zone, was dated at 340 ±2?Ma. This weakly metamorphic zone of supracrustal rocks borders high-grade gneiss terrains in the north and the south, which are intruded by a series of granitoid intrusions: the strongly sheared Schlächtenhaus granite is dated by monazite at 334±2?Ma and the hypothesis of a Devonian emplacement is therefore discarded. The emplacement of all other granites, crosscutting dykes and of an ignimbrite were all within analytical uncertainty: St. Blasien granite 333±2?Ma; Bärhalde granite 332±3?Ma; Albtal granite 334±3?Ma; and a porphyry dyke at Präg 332+2/-4?Ma. Deformation and thrusting of the basement units near the Badenweiler-Lenzkirch zone occurred after the emplacement of the Schlächtenhaus granite, but before the intrusion of the other granitoids, and may therefore be constrained to the time period unresolved between 334±2 and 333±2?Ma. The ignimbritic rhyolite of Scharfenstein was deposited in a caldera 333±3?Ma ago. This age coincides within error limits with published U–Pb monazite and Rb–Sr small slab ages of mimatitic gneisses, Ar–Ar hornblende ages of metabasites and Sm–Nd mineral isochron ages of eclogitic rocks in the underlying basement. This suggests that exhumation and cooling of this basement unit must have been active at rates of approximately 20?km and a few 100°C per million years. The silicic melts are interpreted to be of hybrid crust/mantle origin and their formation was most likely linked to these exhumation tectonics. A phase of mantle upwelling and heat advection into the crust is proposed to be the reason for this short-episodic magmatic pulse.  相似文献   

10.
The Neogene kinematics of the Giudicarie fault (part of Periadriatic lineament, NE Italy) have been re-examined using apatite fission-track analysis. Twenty samples were collected along two geological sections; the first one crossing the Tertiary Corno Alto pluton (Adamello batholith) and the Variscan basement (Southalpine domain) adjacent to the South Giudicarie fault, the second one close to the North Giudicarie fault, in the Variscan basement of the Tonale nappe (Austroalpine system). Samples from the southern section show short tracks and ages between 14.7±1.2 Myr and 22.5±2.2 Myr along 1570 m of the profile; samples from the northern profile present long tracks and ages between 11.3±1.3 Myr and 14.7±3.4 Myr along 1225 m of the vertical profile. In the former, the presence of short tracks might indicate either a long permanence of the rocks in the apatite partial annealing zone, or a more complex thermal history; in the latter case we are dealing with rocks which experienced more rapid cooling.
  The two differing segments of the Giudicarie fault can be explained either as two completely independent tectonic features or, more likely, by hypothesizing a single fault active in its southern and northern parts at different times. Fission track data support a first exhumation of this single fault c. 15 Ma along the North Giudicarie, with a final exhumation towards the south, in the Adamello area, at c. 8–10 Ma (Mid Tortonian). This age fits with the so-called 'Giudicarie' phase, during which σ1 in the stress field was orientated N280–290°.  相似文献   

11.
Four samples from the metamorphic aureole around the Beni Bousera ultramafic massif were studied in detail for U–Th–Pb electron microprobe dating on monazite. The samples include three meta-sedimentary granulites (kinzigites), collected at variable distance from the peridotites, and one kyanite-bearing leucosome in the kinzigite. Two types of monazite were identified in thin section, using SEM. The main population consists of interstitial grains, 20–70  μ m in size, while the second population consists of small grains (<20  μ m), included in garnet. A total of 64 U–Th–Pb electron microprobe measurements on 53 monazite crystals were undertaken. Most crystals have a Pb content lower than the Pb detection limit, indicating that they crystallized, or were reset, during a young event, probably Cainozoic in age. Few crystals, all entirely included in garnet, have Hercynian age, the best estimate of which is 284±27 Ma. This is a direct demonstration of the shielding effect of garnet for the U–Th–Pb system in monazite. The grains in inclusion in garnet are not reset by the post-Hercynian events, despite the high temperature reached at this time (>850 °C). Thus, the monazite closure temperature depends on its textural position in the host rock. The data also show that a Hercynian event occurred in the Beni Bousera granulitic metapelites, which equates with a high- P , high- T  event. The emplacement of the peridotite in the Cainozoic may be linked a low- P , high- T  event, followed by a low- P , low- T  retrogression. These two events reset the U–Th–Pb system in almost all monazite grains, except for the few crystals shielded by garnet.  相似文献   

12.
For many economically important deposits, precise duration and age of hydrothermal ore-formation are poorly known. We tackle these questions for the large Trimouns talc-chlorite deposit by U–Pb analyses of xenotime and monazite, which crystallized within cm-size geodes in the hanging wall dolostones. Formation of geodes and REE-minerals occurred in relation to 300–350°C/0.2–0.3 GPa metasomatism along a host shear zone. Sixteen xenotime fragments, broken off from four single euhedral grains, define an age-range from 112 to 97 Myr, and a monazite age of 99 Myr. Some ages of individual fragments are grain-specific, whereas others show the same range of dates. Given the analytical uncertainties on individual fragments (about ± 1 Myr), the absence of inherited components, and the fact that no thermal event has affected these crystals after their formation, these ages are interpreted to record continuous crystallization between 112 and 97 Ma. This means that the Trimouns deposit was produced by hydrothermal activity lasting for at least 16 million years, occurring along a shear zone through which fluids continuously (or episodically) circulated to allow ion transport from the country gneisses to the deposit locality. Persistent deformation and high heat flow, related to the transtensional regime that opened the Bay of Biscay, seems to be the most likely tectonic scenario to explain this activity.  相似文献   

13.
ABSTRACT Volume diffusion and dislocation creep at T  ∼ 800 °C led to high finite strain in granulite and orthogneiss of the Ohře crystalline complex (North Bohemian shear zone). Intragranular creep by volume diffusion is indicated by (i) lobate phase boundaries between feldspar and quartz, and (ii) removal of perthite lamellae and precipitation of tiny, aluminium-rich needles at the margins of K-feldspar. The striking diffusional-creep structures imply high interfacial free energy that has been preserved from equilibration as a result of rapid cooling. U–Pb dating of monazite (342 ± 1 Ma) and 40Ar–39Ar dating of muscovite (341 ± 4 Ma) of Kadaň orthogneiss result in a cooling rate of 50 + 25/−17 °C Myr−1. This high value is attributed to collapse-related 'elevator-style' movements along the North Bohemian shear zone, resulting in the juxtaposition of upper crustal rocks of the Tepla–Barrandian unit against lower crustal rocks of the Erzgebirge crystalline complex.  相似文献   

14.
Larson  Tullborg  Cederbom  & Stiberg 《地学学报》1999,11(5):210-215
Fission-track thermochronology has been applied to apatite, zircon and titanite from various depths of the Baltic Shield. Burial due to Sveconorwegian (Grenville) and Caledonian foreland sedimentation is revealed.
Titanite and zircon fission-track ages from surface samples (from eastern Sweden) do not vary significantly and average ∼ 850 Myr. It is suggested that Sveconorwegian sediments reached a thickness of at least 8 km in eastern Sweden. Exhumation of these sediments was succeeded by deposition of Lower Palaeozoic cover rocks. Apatite fission-track ages along a transect from SW to NE across the shield, increase from ∼ 300 Myr to ∼ 900 Myr and yield the Phanerozoic history of subsidence and exhumation. Apatite fission tracks, in the basement of the thickest parts of the foreland basin, were totally annealed. These results suggest a > 600 km wide Caledonian foreland basin filled by Devonian sediments that were > 2.5 km thick in southern and western Sweden, thinning to the east (in Finland).  相似文献   

15.
Abstract A metasomatic diopside rock occurs at the top of the dolomitic Connemara Marble Formation of western Ireland and contains titanite and K-feldspar in addition to around 90% diopside ( X Mg= 0.90–0.97). U–Pb isotopic measurements on this mineral assemblage show that the titanite is both unusually uranium-rich and isotopically concordant, with the result that a precise U–Pb age of 478 ± 2.5 Ma can be determined. The age is identical within error to a less precise Rb–Sr age of diopside–K-feldspar of 483 ± 6 Ma. Petrological evidence indicates that the assemblage crystallized at c . 620° C close to or below the closure temperature of titanite. The age thus provides a precise estimate of the time of metamorphism; this age is 11 ± 3 Ma younger than the 490 Ma age for nearby gabbroic plutons which has previously been used to constrain the peak metamorphic age. This difference accords well with geological evidence that the gabbros were emplaced prior to the metamorphic peak. Analysis of minerals with high closure temperature from assemblages whose crystallization is unambiguously associated with a specific episode of fluid infiltration at the peak of metamorphism provides the basis for a new approach to dating metamorphism. The success of this approach is demonstrated by the results from Connemara.  相似文献   

16.
The Strona-Ceneri Zone (Southern Alps) contains folds with moderately to steeply inclined axial planes and fold axes, and amplitudes of up to several kilometres (so-called 'Schlingen'). These amphibolite facies folds deform the main schistosity of Late Ordovician metagranitoids and are discordantly overlain by unmetamorphic Permian sedimentary rocks. Mutually cross-cutting relationships between these folds and garnet-bearing leucotonalitic dykes indicate that these dykes were emplaced during folding. Sm–Nd systematics and the strongly peraluminous composition of these dykes point to an anatectic origin. Pb step leaching of magmatic garnet from a leucotonalitic dyke yielded a 321.3±2.3  Ma intrusive age. Rb–Sr ages on muscovites from leucotonalitic dykes range from 307 to 298  Ma, interpreted as cooling ages during retrograde amphibolite facies metamorphism. Conventional U–Pb data of zircons from an older granodioritic dyke that pre-dates the Schlingen folds yielded discordant U–Pb ages ranging from 371 to 294  Ma. These ages reflect a more complicated multi-episodic growth history which is consistent with the observed polyphase structural overprint of this dyke. Schlingen folding was accompanied by prograde amphibolite facies metamorphism, during the thermal peak of which the leucotonalitic dyke material was generated by partial melting in a deeper source region from where these S-type magmas intruded the presently exposed level. Because partial melting may occur in a relatively late stage of a clockwise P–T–t path, or even during decompression on the retrograde path, we do not exclude the possibility that Schlingen folding had already started in Early Carboniferous time. Schlingen folds also occur in Penninic and Austroalpine basement units with a very similar pre-Alpine history, indicating that Variscan folding affected large segments of the future Alpine realm.  相似文献   

17.
Quantitative thermobarometry in pelites and garnet amphibolites from the Bitterroot metamorphic core complex, combined with U–Pb dating of metamorphic monazite and zircon from footwall rocks, provide new constraints on the P – T  – t evolution of footwall rocks. The thermobarometric and geochronological results, when correlated with observations from other regions bordering the Bitterroot batholith, define a regional metamorphic history for the northern margin of the Bitterroot batholith consisting of three distinct events beginning with early prograde metamorphism (M1) coincident with arc-related magmatism and crustal shortening at c .  100–80 Ma. Magmatism and crustal thickening led to regional upper-amphibolite facies metamorphism (M2) and anatectic melting between 64 and 56 Ma. Mineral textures related to high-temperature isothermal decompression (M3), coincident with late stages of magmatism in the Bitterroot complex footwall (56–48 Ma), are only preserved in areas adjacent to extensional structures. The close temporal relationship between peak metamorphism and the onset of footwall decompression indicates that thermal weakening was an important factor in the initiation of Early Eocene regional extension and tectonic denudation of the Bitterroot complex and possibly the Boehls Butte metamorphic terrane. The morphology of the decompressional P – T  – t path derived for Bitterroot footwall rocks is similar to other trajectories reported for Cordilleran core complexes and may represent a transition in the deformational style of core-bunding detachments responsible for exhumation.  相似文献   

18.
The evolution of Late Paleozoic granitoid magmatism in Transbaikalia shows a general tendency for an increase in the alkalinity of successively forming intrusive complexes: from high-K calc-alkaline granites of the Barguzin complex (Angara–Vitim batholith) at the early stage through transitional from calc-alkaline to alkaline granites and quartz syenites (Zaza complex) at the intermediate stage to peralkaline granitoids (Early Kunalei complex) at the last stage. This evolution trend is complicated by the synchronous development of granitoid complexes with different sets and geochemical compositions of rocks. The compositional changes were accompanied by the decrease in the scales of granitoid magmatism occurrence with time. Crustal metaterrigenous protoliths, possibly of different compositions and ages, were the source of granitoids of the Angara–Vitim batholith. The isotopic composition of all following granitoid complexes points to their mixed mantle–crustal genesis. The mechanisms of granitoid formation are different. Some granitoids formed through the mixing of mantle and crustal magmas; others resulted from the fractional crystallization of hybrid melts; and the rest originated from the fractional crystallization of mantle products or the melting of metabasic sources with the varying but subordinate contribution of crustal protoliths. Synplutonic basic intrusions, combined dikes, and mafic inclusions, specific for the post-Barguzin granitoids, are direct geologic evidence for the synchronous occurrence of crustal and mantle magmatism. The geodynamic setting of the Late Paleozoic magmatism in the Baikal folded area is still debatable. Three possible models are proposed: (1) mantle plume impact, (2) active continental margin, and (3) postcollisional rifting. The latter model agrees with the absence of mafic rocks from the Angara–Vitim batholith structure and with the post-Barguzin age of peralkaline rocks of the Vitim province.  相似文献   

19.
Early Tertiary eclogite facies metamorphism in the Monviso Ophiolite   总被引：2，自引：0，他引：2  
Although crucial for the construction of tectonic models of the Alps the timing of high pressure metamorphism is still poorly determined and controversial. It is likely to vary from one tectonic unit to another depending on when each became involved in subduction. This in turn relates to palaeogeographic position with respect to the active ocean basin. Well defined, reliable geochronological data are too few to test this hypothesis. This paper extends the database by determining Sm–Nd mineral isochrons on two samples from the Monviso Ophiolite in the Piemonte Zone, carefully selected to minimize the problems of Sm–Nd dating of eclogites encountered elsewhere in the Alps. The dated samples have eclogite facies mineral assemblages typical of the Lago Superiore unit of the ophiolite; mineral compositions are similar to previously reported samples and indicate pressures of around 2  GPa and temperatures of 400–500  °C. Sm–Nd isochron ages of 60±12 and 62±9  Ma are defined by garnet and clinopyroxene, while the Rb–Sr age on phengite which is part of the high- P assemblage is 40±1  Ma. The new data fit an emerging pattern of ages in which high- P metamorphism in the oceanic realm is Early Tertiary, with slightly older ages in the overlying Sesia Zone and younger, Oligocene ages in the underlying internal basement massifs which only became involved in subduction when closure of the Piemont ocean was complete.  相似文献   

20.
Abstract The orthopyroxene-clinopyroxene, garnet-orthopyroxene and garnet-clinopyroxene geothermometers, and the garnet-orthopyroxene-plagioclase, garnet-clinopyroxene-plagioclase and anorthite-ferrosilite-grossular-almandine-quartz geobarometers are applied to metabasites and the garnetplagioclase-sillimanite-quartz geobarometer is applied to a metapelite from the Proterozoic Arendal granulite terrain, Bamble sector, Norway. P–T conditions of metamorphism were 7.3 ± 0.5 kbar and 800 ± 60°C.
This terrain shows a regional gradation from the amphibolite facies, into normal LILE content granulite facies rocks and finally strongly LILE deficient granulite facies gneisses. Neither P nor T vary significantly across the entire transition zone. The change in 'grade'parallels the increasing dominance of CO2 over H2O in the fluid phase.
LILE-depletion is not a pre-condition of granulite facies metamorphism: granulites may have either 'depleted'or 'normal'chemistries. The results presented herein show that LILE-deficiency in granulite facies orthogneisses is not necessarily related to variations in either P or T . The important mechanisms in the Arendal terrain were (a) direct synmetamorphic crystallization from magma, with primary LILE-poor mineralogies imposed by the prevailing fluid regime, and (b) metamorphic depletion, involving scavenging of LILEs during flushing by mantle-derived CO2-rich fluids. The latter process is constrained by U–Pb and Rb–Sr isotopic work to have occurred no later than 50 Ma after intrusion of the acid-intermediate gneisses, and was probably associated with contemporary basic magmatism in a tectonic environment similar to a present day cordilleran continental margin.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号