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1.
The western Yunnan area is a natural laboratory with fully developed and best preserved Tethyan orogen in the world. Seismic tomography reveals a slab-like high velocity anomaly down to 250 km beneath the western Yunnan Tethyan orogen, to its west there is a low-velocity column about 300 km wide. In the region from Lancangjiang to Mojiang an obvious low velocity in the lower crust and uppermost mantle overlies on the slab. Synthesizing the available geological and geochemical results, the present paper demonstrates that this slab-like high velocity anomaly is a part of the subducted plate of Yangtze continental segment after the closure of Paleotethys. The collision of India and Eurasia continent starting from 50–60 MaBP might trigger thermal disturbance in the upper mantle and cause the uprising of asthenosphere, in that case the subducted Yangtze plate could be broken off, causing Cenozoic magmatic activities and underplating in the Lancangjiang-Mojiang region.  相似文献   

2.
Seismic tomography reveals that a subducted ancient block has been preserved beneath the Moho of the Dabie-Sulu orogenic belt. Taking into account of geological and geochronological data, we inferred from the tomographic images that the Yangtze block was subducted northward beneath the Sino-Korean block and broken off at the depth <200 km during 200—190 Ma. The slab breakoff of the Yangtze block is the most important dynamic mechanism to control the exhumation of UHP rocks.  相似文献   

3.
Based on detailed field investigations and petrographic observations, we discovered Neoproterozoic-emplaced granite from the metavolcanics of the Dingyuan Formation in the western Beihuaiyang zone, the Dabie orogen. This study reports the results of zircon U-Pb dating and preliminary petrographic observations on two metagranite samples. The studied rocks experienced epidote-amphibolite facies metamorphism and strong structural deformation. Their U-Pb ages are 726 ± 6 and 758 ± 12 Ma, respectively, similar to those for the Luzhenguan complex in the eastern segment of the Beihuaiyang zone. In combination with previously determined 635 ± 5 Ma low-grade metagabbro, this study suggests the occurrence of at least two types of Neoproterozoic intrusive rocks in the Beihuaiyang zone, the northern margin of the South China Block (SCB): 726–758 Ma metagranite and 635 Ma metagabbro. These rocks occur within the metamorphosed Ordovician volcanic zone (originally named the Dingyuan Formation) and are in tectonic contact to each other, but they formed in different tectonic settings. The protolith ages for the Neoproterozoic low-grade metaigneous rocks are in good agreement not only with ages for two episodes of mid- and late-Neoproterozoic mafic and felsic magmatism in the Suizhou and Zaoyang area, Hubei Province, but also agree with protolith ages of ultrahigh-pressure metaigneous rocks in the Dabie-Sulu orogenic belt. In view of their tectonic relationships to country rocks, it appears that these Neoproterozoic low-grade rocks are exotic and they may have been detached and scraped from subducting SCB crust in the early Triassic during the initial continental subduction, and thrusted over Paleozoic metamorphosed rocks in the southern margin of the North China Block during continental collision.  相似文献   

4.
秦汉时期云南西部疆域的确立   总被引:1,自引:0,他引:1  
文章探讨了秦汉时期云南西部疆域的变迁.此间,随着秦开"五尺道"、西汉"开西南夷"置郡县和东汉置永昌郡,自东向西,云南西部疆域逐步推进到澜沧江、怒江以西直至高黎贡山西麓、伊洛瓦底江东岸广大地区,为后世我国西南边疆的空间范畴奠定了基本格局.  相似文献   

5.
扬子陆块西缘康定杂岩的形成时代和构造环境   总被引:1,自引:0,他引:1  
攀西麻粒岩是扬子陆块西缘康定杂岩的重要代表.通过对麻粒岩Rb-Sr、Sm-Nd、40Ar/39Ar和铬石U-Pb测年结果的比较,结合麻粒岩的变质演化历史和岩石地球化学特征分析,认为角闪岩相退变质作用对麻粒岩的Rb-Sr、Sm-Nd和40Ar/39Ar同位素计时体系产生了重要影响.多个岩体锆石U-Pb测年结果的一致性,表明康定岩浆-变质杂岩形成于新元古代(860~750 Ma).岩石的地球化学性质还指示了康定杂岩形成于扬子陆块西缘新元古代活动大陆边缘的岛弧环境.  相似文献   

6.
采用野外采样及室内分析的方法,选取人为干扰较小的旱冬瓜(Alnus nepalensis)林作为对照,对不同利用方式下的土壤生化活性进行分析。结果表明:不同利用类型土壤生化活性之间存在较大差异;土壤生化活性,能比较客观地反映土壤肥力质量的差异和退化程度;除了蔗糖酶活性,不同利用类型的其他土壤生化活性指标均达到了显著影响水平;由土壤生化活性均随着土层深度的增加而降低可以看出,土壤利用类型、人为活动对土壤生化活性的影响主要集中在表层(A层);除了氨化作用,不同土层对其他土壤生化活性指标均达到了显著影响水平。研究区旱冬瓜林土壤性状较好, 其他5 种利用类型土壤均存在不同程度的退化。  相似文献   

7.
云南壮剧的形成有着深厚的历史文化背景。位于滇桂黔泛珠三角地带的滇东南一隅是云南通往内地的重要通道,明清以来商业繁盛,各地客商云集,为云南壮剧的形成创造了条件;文山地区古老而丰富的歌舞艺术资源为云南壮剧的形成提供了取之不尽、用之不竭的艺术养料;明末内地戏曲艺术的传入为云南壮乡埋下了戏曲的种子;清代云南壮剧形成前后大量内地剧种特别是广戏各分支在云南壮乡的演出、传播、交流为云南壮剧的发展壮大奠定了坚实的基础。  相似文献   

8.
High-precision major element and Hf isotope data are reported for the Neoproterozoic Suxiong volcanic rocks along the western margin of the Yangtze Block. These volcanic rocks have variable εHf(T) values and Fe/Mn ratios. The relatively primitive basalts have high Fe/Mn ratios and high Hf-Nd isotopic compositions, indicating that they were generated by partial melting of garnet clinopyroxene in mantle plume at high pressure. Thus, the Suxiong basalts are genetically related to the proposed Neoproterozoic superplume. On the contrary, a few differentiated basalts have low Fe/Mn ratios and low Hf-Nd isotopic compositions. They are likely to experience assimilation-fractional crystallization process. The Suxiong rhyolites have consistent Hf and Nd model ages of 1.3-1.4 Ga. They are likely generated by shallow dehydration melting of pre-existing young arc igneous rocks associated with the basaltic underplating/intrusion in a continental rift.  相似文献   

9.
西方医学在近代云南的传播和发展过程经历了三个大的阶段:教会充当近代西医进入云南的开路先锋,滇越铁路通车后云南迎来了兴办西医院的高潮,抗日战争期间教会医院沿重要交通线加速发展。  相似文献   

10.
The model about block extrusion related to collision between Eurasia and India which is proposed by Tapponnier et al. has not been accepted so far in the field. Based on kinematics and chronology, the Gailigong dextral strike-slip fault in west Yunnan and Nabang dextral strike-slip fault which is the part of Mogok belt are the western boundary of extrusion blocks, as the eastern boundary Red River-Ailaoshan left-lateral fault. And more studies show that as the important way for absorbing the convergence between two continents, the age of blocks’ multistage extrusion is about 23 and 13 Ma.  相似文献   

11.
云南壮剧的语言多姿多彩,丰富生动,具有非常浓郁的民族特点。壮话、当地汉话、广话的综合运用,特殊的语言结构和押韵方式,以及语言艺术的表现方法等,都是别具一格的。  相似文献   

12.
结合《滇南矿厂图略》的内容(主要是下卷),并参考其他文献资料,从运输线路、运输成本、运输管理等方面.对清代云南铸币铜矿的运输问题进行了研究.并对运输线路的变迁作了初步分析.  相似文献   

13.
植物寄生线虫造成的危害极大,开展捕食线虫真菌资源的研究是线虫生物防治的前提和基础.2006年至2007年间对云南西部云南松、华山松松树根际土中的捕食线虫真菌进行了调查,通过对分离到捕食线虫真菌土壤的地理位置、海拔的分析,结果表明:捕食线虫真菌在云南西部松树根际中广泛分布,从1000份样品中共分离、鉴定出捕食线虫真菌3个属(Arthrobotrys,Drechslerella,Dactylellina)21种和5个未产生捕食器的相关属Dactylella以及菌丝不分隔的捕食线虫真Stylopage属的1个种和Tridentaria属的1个种,其中2个为待定种.优势种为Arthrobotrys oligospora,Arthrobotrys musiformis,Arthrobotrys thaumasia,Dactylellina ellipsospora.在所分离到的捕食线虫真菌中,产生粘性菌网的菌种占优势.  相似文献   

14.
Based on the distribution of UHPM rocks on the surface in Sulu terrane, the surface suture between the NCB and SCB should be located along the Wulian fault (see Fig. 1, S1). However, based on the aeromagnetic data of eastern China, Li[1] first indicated that the subsurface suture between the NCB and SCB in the region east of the Tan-Lu fault should be located to the east of Nanjing City (see Fig. 1, S2), which south displaced about 400 km from the surface suture. This is contradicto…  相似文献   

15.
云南省县际经济差异及区域协调发展   总被引:1,自引:1,他引:0  
以云南省129个县市为研究的区域单元,以计量统计分析为基础,定性、定量描述云南县际经济差异状况,提出了县际经济发展类型,探讨县际经济差异随时间动态变化程度,对云南县际经济发展差异的影响因素进行分析,提出区域协调发展的调控措施.  相似文献   

16.
华北和扬子古陆块中新元古代聚合、伸展事件的比较研究   总被引:2,自引:0,他引:2  
区域地质比较研究表明 ,华北和扬子古陆块均具有在中元古代末—新元古代初 (1 1 0 0~ 80 0Ma)陆块聚合及在新元古代 (80 0±Ma)伸展裂解的地质记录 ,并与全球 Rodinia超大陆聚合、裂解的事件相一致 ,但据华北和扬子古陆基底形成的显著差异性 ,以及显生宙陆块漂移、旋转的构造作用推测 ,前震旦纪两古陆块可能不相邻接  相似文献   

17.
Recently ,theinterestinglowlatitudeandlowaltitudeSnowballEarthhypothesis[1,2 ] iswidelyreco gnized ,and greatlystimulatingthestudyoftheNeoproterozoicglaciations ,whichmaybecloselyre latedtothewell knownEarlyCambrianbio radiationevent.By 1980 ,theNeoproterozoicglaciationinSouthChinaisbelievedtobedividedintotwoglaciationsandoneinterglaciation[3~ 5] ,namely ,theearlyChang’anGlaciation ,lateNantuoGlaciationandFu luInterglaciation .However ,thereweredifferentwaysofcorrelation ,themostobvious…  相似文献   

18.
 采用标度变换法,对云南省西北部地区地震活动空间分布的关联维进行了计算,得到了云南西北部不同时段的地震活动空间分布关联维的等值线图.讨论了强震发生前后震中地区关联维演变过程和空间分布特征随时间变化,结果显示,M≥6.0强震发生前存在不同形式的降维过程.  相似文献   

19.
从时代发展角度考察现当代云南少数民族文学,可以看到四个明显进程,即现代文学的探索、新中国国家形象塑造、复苏后的选择和现代性与后现代性背景下的写作。它所展示的乃是时代发展对文学发展的深刻影响力量。在丰富的云南少数民族文学世界中,立足于时代变迁所形成的文化影响,在这种影响中看到文学的历史脉络,将有利于获得云南少数民族文学的历史价值和时代意义。  相似文献   

20.
新闻改革是中国改革开放的一个重要组成部分,因此,在某种意义上说云南媒体的发展历程也是云南省改革开放的一个缩影,正是根据时代发展潮流不断地进行媒体创新,适时地进行角色重构,云南媒体才能在激烈的媒体竞争中保持自己的竞争优势,不断地发展壮大。只有认真总结云南媒体的发展经验,才能更好地适应时代的变迁,使云南媒体业获得更大发展。  相似文献   

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