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1.
The thermochronology based on a combination ofradiometric age and closure temperature (Tc) is widelyaccepted as a sensitive method to provide constraintson tectonic evolution of the orogen, and numerousadvances as a result of thermochronological applica-tions have been made recently in the Dabieshan oro-gen[1—5]. Zircon U/Pb, hornblende Ar/Ar and biotiteAr/Ar ages with Tc= 800—300℃[6] will yield a wealthof information on the cooling and exhumation of rockscrossing crustal levels of 30—1…  相似文献   

2.
During late Mesozoic subduction of paleo‐Pacific lithospheric plates, numerous gold vein deposits formed in the Dabie–Sulu Belt of east‐central China plus its east‐Asian extensions, and in the Klamath Mountains plus Sierran Foothills of northern California. In eastern Asia, earlier transpression and continental collision at about 305–210 Ma generated a high pressure–ultrahigh pressure orogen, but failed to produce widespread intermediate to felsic magmatism or abundant hydrothermal gold deposits. Similarly in northern California, strike‐slip ± minor transtension–transpression over the interval of about 380–160 Ma resulted in the episodic stranding of oceanic terranes, but generated few granitoid magmas or Au ore bodies. However, for both continental margin realms, nearly head‐on Cretaceous destruction of oceanic lithosphere involved sustained underflow; reaching magmagenic depths of about 100 km, the descending mafic‐ultramafic plates dewatered, producing voluminous calc‐alkaline arc magmas. Ascent of these plutons into the middle and upper crust released CO2 ± S‐bearing aqueous fluids and/or devolatilized the contact‐metamorphosed wall rocks. Such hydrothermal fluids transported gold along fractures and fault zones, precipitating it locally in response to cooling, fluid mixing, and/or reactions with wall rocks of contrasting compositions (e.g. serpentinite, marble). In contrast, where sialic crust was subducted to depths of about 100 km, only minor production of granitoid melts occurred, and few major coeval Au vein deposits formed. The mobilization of precious metal‐bearing fluids in continental margin and island arc environments apparently requires long‐continued, nearly orthogonal descent of oceanic, not continental, lithosphere.  相似文献   

3.
Origin of Mesozoic gold mineralization in South Korea   总被引：6，自引：0，他引：6  
Seon-Gyu  Choi  Sung-Tack  Kwon  Jin-Han  Ree  Chil-Sup  So  Sang Joon  Pak 《Island Arc》2005,14(2):102-114
Abstract   The Mesozoic gold–silver deposits in South Korea are closely associated with the Mesozoic granitoids. The Jurassic gold–silver deposits can be distinguished from the Cretaceous ones in terms of occurrence, alteration style, gold fineness, associated mineral assemblage, fluid inclusion and stable isotopic compositions. The Jurassic deposits were formed in mesozonal environments related to deep-seated granitoids, whereas the Cretaceous ones were formed in epizonal environments related to shallow-level granitoids. The Jurassic auriferous deposits (about 165–145 Ma) show fluid characteristics typical of an orogenic-type gold deposit, and were probably generated in a compressional regime caused by an orthogonal convergence of the Izanagi oceanic plate into the Asiatic margin. However, strike-slip faults and caldera-related fractures, together with subvolcanic to volcanic activity, may have played an important role in the formation of Cretaceous gold–silver lode deposits (about 110–45 Ma) under a continental arc setting.  相似文献   

4.
Two alkaline syenite plutons, the Tieshan and Yangfang plutons, have recently been recognized within NE-trending fault zones in eastern Cathaysia, South China. The rocks are very enriched in K2O (6.28–9.39 wt.%), rare earth elements (REE; particularly light REE) and large ion lithophile elements, but are relatively low in high field strength elements. Isotopically, they are characterized by high initial 87Sr/86Sr (0.7093 to 0.7123) and low Nd(t) values (−5.64 to −10.63). The geochemical data suggest that the alkaline syenites most likely formed via fractional crystallization of enriched mantle-derived magmas. Sensitive High-Resolution Ion Microprobe zircon U–Pb dating indicates that these two intrusions have Late Permian (254±4 Ma) and Early Triassic (242±4 Ma) crystallization ages, respectively. Our data suggest that a tectonic regime dominated by transtension probably existed from at least the latest Permian into the Triassic and was responsible for the formation of the Tieshan and Yangfang alkaline syenites. When combined with previous paleomagnetic, structural, and sedimentology data, we suggest that the transtension along the NE-trending strike-slip fault zones was related to oblique subduction of the Pacific plate underneath South China.  相似文献   

5.
The Xiaoxinancha Au-rich copper deposit is one of important Au-Cu deposits along the continental margin in Eastern China. The deposit consists of two sections: the Beishan mine (North), composed of altered rocks with veinlet-dissemination sulfides and melnicovite-dominated sulfide-quartz veins, and the Nanshan mine (South), composed of pyrrhotite-dominated sulfide-quartz veins and pure sulfide veins. The isotope compositions of noble gases extracted from fluid inclusions in ore minerals, i.e. ratios of 3He/4He, 20Ne/22Ne and40Ar/36Ar are in the ranges of 4.45―0.08 Ra, 10.2―8.8 and 306―430, respectively. Fluid inclusions in minerals from the Nanshan mine have higher 3He/4He and 20Ne/22Ne ratios whereas those from the Beishan mine have lower 3He/4He ratios. The analysis of origin, and evolution of the ore fluids and its relations with the ore-forming stages and the ages of mineralization suggests that the initial hydrothermal fluids probably come from the melts generated by partial melting of oceanic crust with the participation of fluids from the mantle (mantle-plume type)/aesthenosphere. This also corresponds to the continental margin settings during the subduction of Izanagi ocaneic plate towards the palaeo-Asian continent (123―102 Ma). The veinlet-dissemination ore bodies of the Beishan mine were formed through replacement and crystallization of the mixed fluids generated by mixing of the ascending high-temperature boiling fluid with young crustal fluid whereas the melnicovite-dominated sulfide-quartz veins were formed subsequently by filling of the high-temperature ore fluid in fissures. Pyrrhotite-dominated sulfide-quartz veins in the Nanshan mine were formed by filling-deposition-crystallization of the moderate-temperature ore fluids and the pure sulfide veins were formed later by filling-deposition-crystallization of ore substance-rich fluids after boiling of the moderate-temperature ore fluids. The metallogenic dynamic processes can be summarized as: (1) formation of fluidand ore substance-bearing Adakitic magma by degassing, dewatering and partial melting during subduction of the Izanagi plate; (2) separation and formation of ore fluids from the Adakitic magma; and (3) success-sive ascending of the ore fluids and final formation of the Au-rich Cu deposit of veinlet-dissemination and vein types by secondary boiling.  相似文献   

6.
Lode gold deposits are among the most economically important types of gold deposits in the world. Globally, they formed mainly in three time intervals, 2.8 to 2.5 Ga, 2.1 to 1.8 Ga, and 700 Ma to the present. Sources of ore-forming fluids and other components are of critical importance in a better understanding of the genesis and the geodynamic controls of these deposits. Although ore-forming fluids were mostly derived from devolatization of sedimentary and/or volcanic sequences during greenschist to amphibolite facies metamorphism associated with orogenic deformation, magmatic hydrothermal fluids have been increasingly shown to be important in many gold deposits in various regions. In this review paper, we summarize the major features of lode gold deposits, possible sources of ore-forming fluids, and mechanisms of gold mineralization. While we acknowledge the critical role of metamorphically derived fluids in the genesis of such deposits worldwide, we emphasize that mantle-or basaltic magma-derived fluids may have been much more important than commonly thought. We use the Liaodong peninsula of the North China Craton as an example to demonstrate the significance of mantle-derived fluids. Integrating earlier studies and new data, we show that some of the late Mesozoic lode gold deposits in the North China Craton may have formed from magmatic hydrothermal fluids due to the extension and partial melting of the hydrated, metasomatized subcontinental lithosphere mantle, as best exemplified by the Wulong gold deposit.  相似文献   

7.
While the high-temperature exhumation process in the Dabie Mountain has been well documented, the low-temperature exhumation of this area since Cretaceous, especially since Late Cretaceous, is relatively less studied. Low-temperature thermochronology provides one of the important approaches to solve this problem. Based on the data of fission track and (U-Th)/He analysis of apaptites and zircons from the granitoid and metamorphic rocks in the Dabie Mountain, this paper applies Mancktelow’s and Braun’s methods to estimating the exhumation rates and to drawing the regional differential exhumation pattern since Cretaceous, especially since Late Cretaceous by taking into consideration factors such as heat transport, heat advection, topography and heat production, which could influence geothermal field in the shallow crust. Since Cretaceous, the exhumation rate (0.08-0.10 km/Ma) in the region around Tiantangzhai and in the south of Tanlu fault zone is larger than the rate (0.04-0.07 km/Ma) in other areas of the Dabie Mountain. The regional differential exhumation pattern might be related to the push-up effect caused by differential strike-slip movement along NNE-trending faults.  相似文献   

8.
The control of synchronous structures on formation of superlarge stratabound ore deposits is immense. Based on studies of ore deposits in South Qiniing, northern Guangdong, Langshan and other areas, three new ideas in comparison with examples of ore control of synchronous structures both in China and abroad are proposed: (i) multiorder ore control of synchronous structures, which means that synchronous structures of different orders display different controls on ore deposits; (ii) synchronous structures in different stages of basin evolution display different controls on basin fluid system and ore-forming system; (iii) synchronous strurture accompanying hydrothermal mineralization as a preexisting weak surface in earth crust often reactivate in later tcctono-thermal event to be a channelway for magma or thermal fluids which superimposed on and reformed preexisting ore beds to form large or superlarge composite ore deposits.  相似文献   

9.
Cenozoic high-K magmatism was vigorously activated in eastern Tibet and controlled by the Early Tertiary pull-apart basins induced by strike-slip faults or Late Tertiary-Quaternary rift basins. These small plutons, dykes and volcanic rocks spatially appea…  相似文献   

10.
The Yarlung Tsangpo Grand Canyon region is located in the frontal zone of the eastern Himalayan syntaxis, where neo-tectonics and seismicity are intensive and closely related to each other. In the region, two sets of fault structures have developed, striking NNE-NE and NWW-NW, respectively. Investigation shows that they differ markedly in terms of scope, property, active times and intensity. The NWW-NW trending faults are large in size, and most are thrust and thrust strike-slip faults, formed in earlier times. The NEE-NE-strike faults are relatively small in size individually, with concentrated distribution, constituting the NNE-trending shear extensional fault zone, which is relatively younger with evident late Quaternary activities. Strong earthquakes occur mainly in the areas or zones of intensive differential movement of the Himalayas, e.g. along the deep and large fault zones around the crustal blocks. Most earthquakes of M≥7.0 are closely related to tectonics, where large-scale Holocene active faults are distributed with complicated fault geometry, or the faults of multiple directions intersect. Among them, earthquakes of M≥7.5 have occurred on the NW and NE-trending faults with a greater strike-slip component in the fault tectonic zones.  相似文献   

11.
The Litang fault zone (LFZ) is an important active fault within the northwestern Sichuan sub-block. To-gether with the Garzê-Yushu, Xianshuihe, and An-ninghe fault zones on its northern, eastern and south-eastern sides, the LFZ constitutes the lateral extrusion tectonic system in the southeastern part of the Qing-hai-Tibetan Plateau[1,2] (Fig. 1). According to instru-mental records, historical recordings and field investi- gation, an earthquake (Ms7.3) occurred on its middle to south se…  相似文献   

12.
Independent of Indochina extrusion, the South China Sea experienced a process from passive continental rifting to marginal sea drifting. According to the fault patterns in the Beibu Gulf basin and the Pearl River Mouth basin, the continental rifting and early spreading stage from 32 to 26 Ma were controlled by extensional stress field, which shifted clockwise from southeastward to south southeastward. From 24 Ma on, the sea spread in NW-SE direction and ceased spreading at around 15.5 Ma. Integrated geological information with the assumption that the South China Sea developed along a pre-Cenozoic weakness zone, we did analogue experiments on the South China Sea evolu- tion. Experiments revealed that the pre-existing weakness zone goes roughly along the uplift zone between the present Zhu-1 and Zhu-2 depression. The pre-existing weakness zone is composed of three segments trending NNE, roughly EW and NEE, respectively. The early opening of the South China Sea is accompanied with roughly 15° clockwise rotation, while the SE sub-sea basin opened with SE extension. Tinjar fault was the western boundary of the Nansha block (Dangerous Ground), while Lupar fault was the eastern boundary of the Indochina, NW-trending rift belt known as Zengmu basin developed between above two faults due to block divergent of Indochina from Nansha. In the experiment, transtensional flower structures along NW-trending faults are seen, and slight inversion occurs along some NE-dipping faults. The existence of rigid massifs changed the orientations of some faults and rift belt, and also led to deformation concentrate around the massifs. The rifting and drifting of the South China Sea might be caused by slab pull from the proto South China Sea subducting toward Borneo and/or mantle flow caused by India-Asia collision.  相似文献   

13.
滇西南地区孟连断裂晚第四纪走滑速率的厘定   总被引：1，自引：1，他引：0       下载免费PDF全文
通过卫星影像解译和野外实地调查,获得滇西南地区孟连断裂的几何特征和活动性参数。孟连断裂总体走向NE-NEE向,不具有明显的分段性,连续性较好。断裂从单侧控制着沿线的勐滨、孟连和勐马三个新生代盆地的发育。断裂沿线地貌以线性较好的断层谷、断层崖和断层陡坎为主,并发育多级左旋位错的河流、冲沟和阶（台）地等,观测到的最小左旋位错约为7 m。采用高精度Li-DAR测量方法,对4处典型水平位错地貌进行精细测量,根据获得的相应地貌面年代,得到孟连断裂晚第四纪以来平均左旋走滑速率为2.2±0.4 mm/a。其结果与滇西南地区其他NE向左旋走滑断裂滑动速率相当,反映了区域构造活动的整体协调性。根据跨断层地质体最大左旋位错量9.5±1.8 km,估算断裂开始左旋走滑的时代为距今4.7±1.6 Ma左右,即中新世中晚期。  相似文献   

14.
Opening of the Japan Sea back arc basin was accompanied by extensional tectonics in the drifting southwest Japan arc. Various trends of Early Miocene grabens in the arc suggest multi-directional rifting, which necessarily involved strike-slip components of some of basin-margin faults. However, such components are not well understood. In this work we conducted a field survey in the Early Miocene Ichishi basin on the northern side of the Median Tectonic Line, central southwest Japan. We found that the basin was a compound of grabens that were formed along normal and sinistral strike-slip faults, the latter of which had northeast–southwest trends. The block faulting in this phase produced basement highs between sub-basins, which were filled with the lower part of the Ichishi Group. We found a low-angle angular unconformity at a middle horizon in the group, with which we define the upper and lower part of the group. The upper part onlapped both the basement highs and the lower part. It means that the transtensional basin formation ceased sometime between 18 and 17.5 Ma in the Ichishi area. The Ichishi basin turned subsequently into a sag basin subsided due to normal faulting probably along the Nunobiki-sanchi-toen fault zone. The transtension and the basin sag were driven by ENE–WSW extensional stress. This arc-parallel extension produced grabens various areas including Ichishi in the Early Miocene. The extensional deformation was eventually localized to the deep rift along the Fossa Magna to make the lithosphere under southwest Japan decoupled from that under northeast Japan. The decoupling allowed the rapid rotation of southwest Japan from ~17.5 Ma. The cluster of those grabens around the Ise bay probably determined the southeastern margin of the Kinki triangle.  相似文献   

15.
The three-dimensional arrangement of volcanic deposits in strike-slip basins is not only the product of volcanic processes, but also of tectonic processes. We use a strike-slip basin within the Jurassic arc of southern Arizona (Santa Rita Glance Conglomerate) to construct a facies model for a strike-slip basin dominated by volcanism. This model is applicable to releasing-bend strike-slip basins, bounded on one side by a curved and dipping strike-slip fault, and on the other by curved normal faults. Numerous, very deep unconformities are formed during localized uplift in the basin as it passes through smaller restraining bends along the strike-slip fault. In our facies model, the basin fill thins and volcanism decreases markedly away from the master strike-slip fault (“deep” end), where subsidence is greatest, toward the basin-bounding normal faults (“shallow” end). Talus cone-alluvial fan deposits are largely restricted to the master fault-proximal (deep) end of the basin. Volcanic centers are sited along the master fault and along splays of it within the master fault-proximal (deep) end of the basin. To a lesser degree, volcanic centers also form along the curved faults that form structural highs between sub-basins and those that bound the distal ends of the basin. Abundant volcanism along the master fault and its splays kept the deep (master fault-proximal) end of the basin overfilled, so that it could not provide accommodation for reworked tuffs and extrabasinally-sourced ignimbrites that dominate the shallow (underfilled) end of the basin. This pattern of basin fill contrasts markedly with that of nonvolcanic strike-slip basins on transform margins, where clastic sedimentation commonly cannot keep pace with subsidence in the master fault-proximal end. Volcanic and subvolcanic rocks in the strike-slip basin largely record polygenetic (explosive and effusive) small-volume eruptions from many vents in the complexly faulted basin, referred to here as multi-vent complexes. Multi-vent complexes like these reflect proximity to a continuously active fault zone, where numerous strands of the fault frequently plumb small batches of magma to the surface. Releasing-bend extension promotes small, multivent styles of volcanism in preference to caldera collapse, which is more likely to form at releasing step-overs along a strike-slip fault. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

16.
There are two main ocean-ridge discontinuities in Iceland: the Tjörnes Fracture Zone (TFZ) and the South Iceland Seismic Zone (SISZ). The TFZ is a 120-km-long and as much as 70-km-wide WNW-trending zone of high seismicity. It has three main seismic lineaments: the Husavik-Flatey Fault (HFF), the Dalvik lineament, and the Grimsey lineament. The HFF, a dextral strike-slip fault and active as a transform fault for about 9 Ma, has a cumulative transform-parallel displacement of some 60 km. Offshore, the HFF is marked by a transform (fracture-zone) valley, 5–10 km wide and 3–4 km deep. Onshore the Flateyjarskagi Peninsula the HFF is marked by a 3–5-km-wide zone of intense crustal deformation with numerous strike-slip and normal faults, transform-parallel dykes, dense sets of mineral veins, and subzones of completely crushed rocks, that is, fault cores. Where the HFF comes on land on Tjörnes there is a similar, but much thinner, zone of crushed rocks. The seismic lineaments are located a few tens of kilometres south (Dalvik) and north (Grimsey) of, and run subparallel with, the HFF. Both lineaments are composed of sets of NNW-trending sinistral faults arranged en echelon.The SISZ is a 70-km-long and 10–20-km wide zone of almost continuous seismicity located between the overlapping West and East Volcanic Zones. It produces the largest earthquakes in Iceland, some of which exceed M7, during which the N–S width of the zone may be as great as 50–60 km. The SISZ is partly covered with Holocene lava flows where the seismogenic faults occur as dextral NNE-trending and sinistral ENE-trending conjugate arrays with push-ups between their nearby ends. The same fault-segment trends occur in the Pleistocene pile north of the Holocene lava flows.The HFF is neither perpendicular to the nearby ridge segments nor parallel with the spreading vector. As a consequence, the North Volcanic Zone has propagated to the north and the Kolbeinsey Ridge to the south during the past 1 Ma, resulting in the development of the Grimsey and Dalvik lineaments. Similarly, the tip of the East Volcanic Zone has been propagating rapidly to the southwest during the past 3 Ma. The tip has been at its present location for no more than several hundred thousand years, thus making the SISZ less stable than the HFF. If the propagation of the tip of the East Volcanic Zone continues, it will eventually reach the Reykjanes Ridge, whereby either the West or the East Volcanic Zone becomes extinct. Then the SISZ dies out as a major seismic zone.  相似文献   

17.
The Kuoerzhenkuola gold field (including the Kuo- erzhenkuola and the Buerkesidai gold deposits), lo- cated 68 km east of Jimunai County in northern Xing- jiang, China, is an important component of the Sawuer gold belt which is the eastward extending part of the Zarma-Sawur gold-copper belt in Kazakhstan. Some studies are concerned with the geology of the gold ores[1―3], the associated volcanic rocks[4], radiogenic isotope[5―8], and the ore-forming environment[8]. Most researchers inferr…  相似文献   

18.
最新GPS观测资料研究表明喜马拉雅东构造结周边主要断裂带在不同构造部位其运动特征不同.雅鲁藏布江断裂总体表现为右旋挤压运动,东构造结以西走滑速率为2~4 mm/a、挤压速率为1~4 mm/a,东构造结附近走滑速率为6~7 mm/a、挤压速率为1~4 mm/a;嘉黎断裂带从东构造结以西的右旋走滑运动,到东构造结附近的弱右旋走滑运动,转变为东构造结东南部的左旋走滑运动,走滑速率分别为4~6 mm/a、1~2 mm/a和3~5 mm/a.怒江断裂带在构造结以西主要为挤压运动,运动速率1~2 mm/a;在东构造结及其东南部则表现为右旋挤压运动,走滑速率为2~3 mm/a、挤压速率1~2.5 mm/a.以上结果表明,尽管东构造结形成于中生代,但现今对周边主要断裂带的运动仍有一定的影响;嘉黎断裂带东南段可能不是青藏高原右旋剪切带的南部边界.  相似文献   

19.
对白垩纪-古近纪洞庭盆地东部湘阴凹陷的北部进行了地表地质调查与研究。凹陷呈NE走向,沉积岩层倾向南东,且自南东往北西倾角变陡。凹陷南段宽、北段窄,其南东边界分别为倾向NW的公田断裂和忠防断裂,两断裂之间以走向NW、倾向南西的白羊田断裂和石姑桥断裂相连接。公田断裂为正断裂,白羊田断裂和石姑桥断裂为右旋平移正断裂,忠防断裂为左行平移正断裂;公田断裂和石姑桥断裂均经历了自韧性→脆性的转变过程。凹陷内部发育NE~NNE向小型同成盆正断裂。上述信息表明：①湘阴凹陷为箕状断陷盆地;②公田断裂和忠防断裂的拉张活动控制了凹陷的形成和发展,区域N（N）E向左旋走滑应力场对凹陷北段有一定影响;③白羊田断裂和石姑桥断裂属横向调整断裂;④凹陷发展及其沉积充填,与南东面幕阜山隆起的抬升与剥蚀（包括沉积剥蚀和构造剥蚀）相耦合。结合区域资料,讨论认为湘阴凹陷形成的伸展构造环境受本地区特有的地幔上隆深部构造背景与中国东南部区域张性构造环境的双重制约,并以前者为主;凹陷走向主要受区域NNE向左行走滑应力场的控制。  相似文献   

20.
基于活动块体的基本概念,综合对研究区内活动断裂带空间展布、地震活动性等资料的分析将巴颜喀拉块体东部及邻区划分为巴颜喀拉块体（I）、华南块体（Ⅱ）、川滇块体（Ⅲ）和西秦岭块体（IV）等4个一级块体.利用GPS形变场、地球物理场等资料结合F检验法,将巴颜喀拉块体划分为阿坝（I1）、马尔康（I2）和龙门山（I3）3个次级块体,将西秦岭块体划分为岷县（IV1）和礼县（IV2） 2个次级块体.利用分布在各个块体内部的GPS测站,计算各活动块体及块体边界断裂带的运动变形特征.结果表明：各活动块体的整体运动包括平移和旋转运动;东昆仑断裂带、甘孜—玉树断裂带和鲜水河断裂带的滑动速率明显高于龙门山断裂带的滑动速率;巴颜喀拉块体东部走向北西或北西西的边界断裂表现出左旋拉张的特性;走向北东的边界断裂带,除成县—太白断裂带外,均表现出右旋走滑兼挤压的活动特征.巴颜喀拉块体的东向运动存在自西向东的速度衰减,衰减主要被龙日坝断裂带和岷江断裂带分解吸收,其中龙日坝断裂带的水平右旋分解非常明显,约为~4.8±1.6 mm/a,岷江断裂带的水平分解较弱.龙门山断裂带被马尔康、龙门山和岷县等次级块体分成南、中、北三段,龙门山断裂带中段上的主压应变率要明显小于龙门山断裂带南段上的应变率,其北西侧变形幅度从远离断裂带较大到靠近断裂带逐渐减小,表明其在震前已经积累了较高的应变能,有利于发生破裂滑动.汶川地震后,地表破裂带和余震分布揭示的断裂带运动性质自南西向北东由以逆冲运动为主,逐渐转为逆冲兼走滑的特征可能与龙门山断裂带中段所受主压应力方向自南西向北东的变化有关.马尔康、龙门山和岷县3个次级块体与华南块体之间较低的相对运动速度以及龙门山断裂带低应变率、强闭锁的特征都决定了汶川地震前龙门山断裂带低滑动速率的运动特征.  相似文献   

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