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31.
辽东海岸带黄土   总被引:19,自引:1,他引:19  
本文论述了辽东海岸带黄土的成因,它主要由低空气流搬运的近源物质组成,其次为高空气流携带的内陆远源物质,主要物源地是辽东湾。冰期时,海平面下降,辽东湾干口渤海裸露成陆而发生沙漠化,海底沉积物经强劲的西北风作用,被搬运到东侧海岸带沉降下来,与大气环流系统自内陆携带而至的风尘物质混合在一起,形成海岸带黄土。  相似文献   
32.
New hadrosaurid material is recorded from Fontllonga (Ager syncline, province of Lleida), in the Catalonian Pyrenees, comprising a dentary with part of the dental battery, recovered from Late Maastrichtian strata (Tremp Formation), close to the presumed Cretaceous/Tertiary boundary. This hadrosaurid is more derived than is Telmatosaurus transsylvanicus from the Haeg Basin (Romania), but lacks a number of features that diagnose the clade Hadrosaurinae plus Lambeosaurinae. It is attributed to the Euhadrosauria on the basis of the following synapomorphies: dentary teeth not recurved distally, narrow dentary crowns, and denticles not supported by subsidiary ridges. The phylogenetic relationships of the best-known iguanodontids and hadrosauroids are evaluated using mandibular and dentary tooth characters. On the basis of a cladistic analysis, the family of Hadrosauridae is diagnosed by more than 29 dentary tooth positions, parallel-sided vertical furrows formed by dentary alveoli, and absence of caudal secondary ridges. Within Hadrosauridae, successive sister-groups of Hadrosaurinae plus Lambeosaurinae are the Fontllonga taxon and Telmatosaurus. The clade Hadrosaurinae plus Lambeosaurinae is characterised mainly by a coronoid process inclined rostrally and by the absence of secondary ridges on dentary crowns. The Fontllonga find suggests the diversity of European hadrosaurids at the end of the Cretaceous to have been greater than previously thought. Moreover, the primitive character of European hadrosaurids as compared to western North American and Asian relatives may be explained in terms of geographical isolation during the Late Cretaceous.  相似文献   
33.
1 INTRODUCTIONTropical cyclones (TCs) moving north and gettingto the Liaodong Peninsula and waters of the Yellowand Bohai Seas are in their late phase of life cycle.While weakening rapidly, TCs carry a large amount ofwarm and humid air that forms heavy ra…  相似文献   
34.
徐征和  陈吉亭  刘健勇  樊向阳 《地下水》2006,28(3):78-80,104
胶东半岛滨海区由于水资源的综合开发利用不合理,地下水位大幅度下降,形成区域性的下降漏斗,海水入侵严重,导致一系列生态环境问题产生.本文集成利用地下水回灌补源生态修复技术,通过自然或人工工程补源技术进行地下水储存,实现了区域地表水、地下水资源联合调度时空调配运用,取得了水资源利用经济、社会和环境等综合效益的高效统一.  相似文献   
35.
Considerable debate on whether and how the Sulu Orogenic Belt extends eastward to the Korean Peninsula has remained over the past decade. New results reported here include the following: (1) an eclogite and retrograded eclogite-bearing complex (Hongseong Complex) is discovered in South Korea, in which the eclogite occurs as lenses in circa  810–820 Ma granitic gneiss. SHRIMP zircon dating of the eclogite yields  230 Ma for the metamorphic age and  880 Ma for the protolith age; (2) The basement of the Rangnim, Gyeonggi and Yeongnam massifs have affinities to the basement of the North China Block (NCB). However the Gyeonggi Massif encloses a minor amount of large or small slabs of the Hongseong Complex that are similar to the rocks of the Sulu Belt. (3) Two main Paleozoic basins within the Rangnim and Gyeonggi massifs have a similar Paleozoic tectono-stratigraphy to the NCB. (4) The Imjingang and Ogcheon belts do not exhibit any metamorphic characteristics of collisional orogenic belts. Based on these facts, we propose a crustal-detachment and thrust model and suggest that the collision belt between the Yangtze Block (YB) and NCB (Sino–Korea Craton) is preserved along the western margin of the Korean Peninsula. The lower part of the UHP metamorphosed lithosphere of the YB was subducted under the Korean Peninsula and not uplifted to the surface. The lower crust of the YB (the Hongseong Complex) was detached from the subducted lithosphere and thrust over the Korean Peninsula, and inserted into the basement rocks of the Gyeonggi Massif. The upper crust of the YB possibly was detached from the lower crust and overthrusted along the Honam and Chugaryong shear zones. The Imjingang and Ogcheon belts possibly represent the detached upper crust of YB and their present occurrences are controlled by a Mesozoic strike–slip shear structure. All these detached lower and upper crustal slabs were strongly deformed during the Late Jurassic and Early Cretaceous tectonic event leading to their present geological distribution and characteristics.  相似文献   
36.
山东胶东半岛地区断裂最新活动性研究   总被引:5,自引:2,他引:5  
山东胶东半岛地区发育有北北东-北东向和北西西向两组断裂,前者分属蓬莱-栖霞断裂系和即墨-牟平断裂带,为半岛的主体断裂构造;后者分布在半岛北缘及其北侧海域,由多条断裂组成。实地调查表明,断层在第四纪期间是活动的,控制着附近山地和盆地的构造演化与地貌发育,最新活动主要发生在第四纪早期,垂直活动幅度可达百米以上;第四纪晚期,断裂活动性迅速减弱,甚至停止,但依然发现北北东-北东向断裂的多个局部段落还在活动,明显地错断了晚更新世地层,垂直断距最大为10m左右。  相似文献   
37.
1975年中国海城7.3级地震波及整个朝鲜半岛,乃至日本九州地区. 本文系统收集了该震有关资料,并通过整理分析勾画出其烈度分布,以探讨该震的震害特点. 在半岛的北部, 除局部地区为Ⅵ度之外,大部分地区为Ⅴ度区,其震害情况与相同烈度的典型特征基本相符; 半岛南部大部分地区为Ⅳ度区. 然而,韩国首尔等大城市,除高层建筑强烈振动之外,还有人出现眩晕症状等特别的感觉,个别街区变压器跳闸造成一时停电. 这些可能是大震的长周期波在远场的效应所致.   相似文献   
38.
We interpreted marine seismic profiles in conjunction with swath bathymetric and magnetic data to investigate rifting to breakup processes at the eastern Korean margin that led to the separation of the southwestern Japan Arc. The eastern Korean margin is rimmed by fundamental elements of rift architecture comprising a seaward succession of a rift basin and an uplifted rift flank passing into the slope, typical of a passive continental margin. In the northern part, rifting occurred in the Korea Plateau that is a continental fragment extended and partially segmented from the Korean Peninsula. Two distinguished rift basins (Onnuri and Bandal Basins) in the Korea Plateau are bounded by major synthetic and smaller antithetic faults, creating wide and considerably symmetric profiles. The large-offset border fault zones of these basins have convex dip slopes and demonstrate a zig-zag arrangement along strike. In contrast, the southern margin is engraved along its length with a single narrow rift basin (Hupo Basin) that is an elongated asymmetric half-graben. Analysis of rift fault patterns suggests that rifting at the Korean margin was primarily controlled by normal faulting resulting from extension rather than strike-slip deformation. Two extension directions for rifting are recognized: the Onnuri and Hupo Basins were rifted in the east-west direction; the Bandal Basin in the east–west and northwest–southeast directions, suggesting two rift stages. We interpret that the east–west direction represents initial rifting at the inner margin; while the Japan Basin widened, rifting propagated southeastward repeatedly from the Japan Basin toward the Korean margin but could not penetrate the strong continental lithosphere of the Korean Shield and changed the direction to the south, resulting in east–west extension to create the rift basins at the Korean margin. The northwest–southeast direction probably represents the direction of rifting orthogonal to the inferred line of breakup along the base of the slope of the Korea Plateau; after breakup the southwestern Japan Arc separated in the southeast direction, indicating a response to tensional tectonics associated with the subduction of the Pacific Plate in the northwest direction. No significant volcanism was involved in initial rifting. In contrast, the inception of sea floor spreading documents a pronounced volcanic phase which appears to reflect asthenospheric upwelling as well as rift-induced convection particularly in the narrow southern margin. We suggest that structural and igneous evolution of the Korean margin, although it is in a back-arc setting, can be explained by the processes occurring at the passive continental margin with magmatism influenced by asthenospheric upwelling.  相似文献   
39.
辽东半岛南部早古生代地层发育,其中馒头组—冶里组的沉积过程,具有完整的陆源碎屑岩—碳酸盐岩堆积特点。从层序划分、沉积环境演化、古气候变迁等方面分析,馒头组—冶里组反映了一个完整的碳酸盐岩台地的发展过程,可划分出准备阶段(形成碎屑岩垫板)、生长—发育阶段(形成碳酸盐岩缓坡)及衰亡阶段(发育白云岩盖层)。  相似文献   
40.
A heat flow isoline map is presented. Low and relatively constant heat flow has been observed in the old shield areas of the East European Platform (25–40 mW/m2). Increased heat flow (>50 mW/m2) has been found in the Dniepr-Donetz depression. The area south of the East European Platform is characterized by highly variable heat flow (55–100 mW/m2). Some geophysical implications are discussed.  相似文献   
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