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81.
Until now, no satisfactory geodynamic model has been delivered concerning the three main West African orogens: Panafrican 1 (Bassaride belt), Panafrican 2 (Rokelide belt) and Hercynian (Mauritanide belt). However, since the last synthetic paper (Villeneuve, 2008), new geological, geophysical and geochronological data, from the Moroccan Sahara to Sierra Leone, allow us to propose a new geodynamical model. It includes the two Panafrican events in a single model very similar to the present western Pacific margin. An old “West African Neoproterozoic ocean” (WANO) was limited by a set of island arcs separated from the West African craton by a series of “back arc basins”. The closure of this first round of back arc basins around 650 Ma led to the Bassaride belt (Panafrican 1). Then the WANO was subducting underneath the island arcs (between 650 and 550 Ma) meanwhile a new generation of “back arc basins” opened to the east between the arcs and the craton margin. The closure of the WANO and associated island arcs and back arc basins (550 to 500 Ma) led to the Rokelide belt (Panafrican 2). The Hercynian structures involving a Palaeozoic cover (made with continental material) associated to a “greeenschist facies” metamorphism is ascribed to an intracontinental belt.  相似文献   
82.
和凯里生物群一样,贵州寒武系杷榔动物群也含有丰富的棘皮动物始海百合化石,包括两个属种即俞氏贵州始海百合 GuizhoueocrinusyuiZhao,ParsleyetPeng,2007及殷氏原始球状始海百合(新属新种)Protogloboeocrinusyini(gen.etsp. nov.).其中新属种是近期在杷榔组分布区南部贵州麻江下司淑里村杷榔组上部发现的,是凯里组中球形球状始海百合(GloboeocrinusglobolusZhao, ParsleyetPeng,2008)的原始属种,两者均具有发育的吸盘、长的茎、近于球形或椭球形的萼及较长 的腕.但新属种茎呈倒长锥柱形,缝孔长卵形,腕枝数少,两者区别明显.Protogloboeocrinusyini(gen.etsp.nov.)的发现及研 究,不仅追溯到凯里组球形球状始海百合的原始属种,了解两者演化规律是茎变短,萼变球形,缝孔变为圆形,腕枝数量增加, 捕食能力增强.而且还增添了杷榔组始海百合的多样性及其分区性:杷榔组分布区北部仅见Guizhouocrinusyui,南部仅见 Protogloboeocrinusyini(gen.etsp.nov.)   相似文献   
83.
The paper describes an early and primitive sauropod dinosaur, Gongxianosaurus shibeiensis (gen. et sp. nov.), from the Dongyuemiao Member of the Lower Jurassic Ziliujing Formation in Shibei Township, Gongxian County, Sichuan Province, China, which is one of the 5 dinosaur fossils discovered in Gongxian in 1997. Except the skull which is incomplete, the fossils are well preserved. It has some features of both sauropods and prosauropods. It is an intermediate type in the evolution of dinosaurs from prosauropods to sauropods and provides materials for the study of the origin and evolution of the sauropod dinosaur fauna. The discovery of this new sauropod furnishes a way for the stratigraphic correlation between the Early Jurassic Ziliujing Formation in the Sichuan basin and the Lower Jurassic Lufeng Formation in the Central Yunnan basin.  相似文献   
84.
Paraelectrentomopsis chenyangcaii gen. et sp. nov. from the Cretaceous Burmese amber is characterized, described, illustrated and its position is discussed. This fossil taxon is the second compsocid barklouce to be described from the Burmese amber and constitute one of the earliest records of the family. A checklist of known Compsocidae is given. Identification keys of all known Compsocidae are provided. A palaeobiogeography scenario is proposed.  相似文献   
85.
张抗 《地质科学》2009,44(4):1105-1112
断块说形成过程充分表现了张文佑先生广蓄并纳继承创新的治学思路。在1956~1958年主持编纂的1∶5 000 000中国大地构造图及其说明书《中国大地构造纲要》和20世纪80年代初期完成的1∶5 000 000中国及邻区海陆大地构造图及其说明书《断块构造导论》是其发展两大阶段的标志。古中国大陆在断裂体系影响下破碎分离再逐步拼合的过程中形成稳定断块与活动带相间的格局; 拉张造洋挤压造陆,洋、陆型地壳互相转化等两大学术观点的提出是其重大理论创新。断块说在解释中国及邻区大地构造中不断发展并融合了其它学术流派,断块开合说的提出即是其表现之一。立足亚洲-西太平洋复杂的地质构造断块说可望得到进一步发展。  相似文献   
86.
Basic magmatism in central Spain occurred sporadically during a long period of ca. 140 Ma. The geochemical data on representative samples from the five igneous episodes show that different mantle reservoirs were tapped. Crustal involvement (via recycling in mantle sources or by hybridization at emplacement levels) was important in the basic magmas related to the Hercynian orogeny (Gb1 to Gb3 suites). Samples occurring as later dykes have signatures ranging from OIB-like values (Gb4 alkaline lamprophyres) to those of a formerly enriched subcontinental lithospheric mantle (tholeiites Gb5). To cite this article: C. Villaseca et al., C. R. Geoscience 336 (2004).  相似文献   
87.
论漳州盆地的成因--是差异侵蚀盆地而非断陷盆地   总被引:1,自引:0,他引:1  
李国华 《地质论评》2008,54(2):199-206
依据漳州盆地及其外围诸多小盆地之盆地边界大多数与在盆地占位的花岗闪长岩体边界一致,且沉积层薄,山足面大,盆周高度主要受酸性—中酸性火山岩或超浅成酸性岩体控制,并缺乏控制盆地形成之正断层的直接地质证据,进而依据岩性差异剥蚀率,论证了漳州盆地为差异侵蚀成因,而不是断陷盆地。对该类盆地成因类型的确定,对该地区地震监测有重要意义。  相似文献   
88.
A partial skull comprising fused maxilla/premaxilla and palate of a ctenochasmatoid pterosaur from the Santana Formation of the Araripe Basin in NE Brazil is named as the new genus and species Unwindia trigonus gen. et sp. nov. on account of its long slender rostrum, isodonty with raised dental alveoli and dentition of seven tooth pairs restricted to the portion of the rostrum anterior to the nasoantorbital fenestra. Unwindia is assigned to the Ctenochasmatoidea, and is probably basal within the clade.  相似文献   
89.
Sinoprotodiplatys zhangi gen. et sp. nov. is described from the Lower Cretaceous Yixian Formation in Liaoning Province, near Beipiao City, China. It is one of the most recent representatives of the suborder Archidermaptera. The classification and synonymies among the archidermapteran families are reassessed. The palaeosynecological evolution of the Mesozoic earwigs is analysed using the new tool of the ‘Wagner Parsimony using Morphological Characters’ method (‘WAPUM’), suggesting that the evolution of the morphology of these insects was very progressive, perhaps owing to their way of life in the soil.  相似文献   
90.
SWAT模型在漳卫河流域应用研究   总被引:26,自引:0,他引:26  
漳卫河流域是海河流域重要组成水系, 也是我国北方地区水资源短缺和水环境恶化的典 型区域之一。本文基于SWAT(Soil and Water Assessment Tool)构建漳卫河流域分布式水文模型, 对模型的几个重要参数进行敏感性分析, 总结出其取值变化对模拟结果的影响规律。并应用 2000~2004 年的水文气象数据, 进行分布式水文过程模拟, 将模拟结果与8 个行政区划的水资源 公报数据进行对比分析。结果显示模拟相对误差在10%以内, 能够为水资源管理提供重要参考。 研究成果对于SWAT 模型在国内的应用和推广, 具有很好的示范性。也为海河全流域分布式水文 模型的研制奠定了基础。  相似文献   
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