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 共查询到16条相似文献,搜索用时 78 毫秒
1.
Several thrust faults have been mapped in theYanshan belt ,as the thrust structure was first iden-tified by Wong (1928) (Ji et al .,2005 ; Wang et al .,2005a ;Davis et al .,2001 ,1998 ; Yang et al .,2001 ;Zheng et al ., 2000 ; Chen, 1998 ; Zhang et al .,1986 ; He ,1957 ;Chern and Hsiung,1935) .Becausethe Archean basement was widely involved in thethrust systemof the Yanshan belt ,domestic popularrecognition emphasized the thick-skinned characteris-tics and li mited horizontal displacement…  相似文献   

2.
A New Ornithocheirid from the Early Cretaceous of Liaoning Province, China   总被引:5,自引:0,他引:5  
Based on a nearly complete skeleton with skull from the Early Cretaceous of Liaoning Province, a new ornithocheirid pterosaur: Boreopterus cuiae gen. et sp. nov. is erected. Boreopterus cuiae is different from other pterosaurs preserved with skulls known from the western Liaoning Province and its neighboring areas. Tiffs new oterosaur has more and larger teeth than those in other ornithocheirids. Its anterior nine pairs of teeth are larger than other teeth. The fourth pair of upper and lower teeth are slightly larger than the third pair. Overall, Boreopterus cuiae shows much small range of tooth size variation than Anhanguerapiscator and Coloborhynchus robustus. The new taxon shares with other ornithocherids in having a relatively large size of the third and fourth pairs of teeth.  相似文献   

3.
A new species of Huaxiapterus: H. benxiensis sp. nov. is erected based on the new specimen. The diagnostic characters of Huaxiapterus benxiensis are well-developed premaxillary crest and parietal spine, the crest and spine parallel and extending posterodorsally, and a shallow groove present on the dorsal surface of the anterior portion of the mandibular symphysis. The different skull morphologies of Chinese tapejarid pterosaurs indicate that they are much more diverse than the previous thought.  相似文献   

4.
《福建地质》2012,31(1)
永安小磉调查区大面积出露外来推覆体即寒武系中一下统林田组、上统东坑口组,泥盆系上统天瓦崃组、桃子坑组,石炭系下统林地组、中统黄龙组、上统船山组,利用推覆构造理论,并结合深部钻探验证,推覆体下保存较厚煤系(童子岩组)和可采煤层,找煤潜力大,推覆构造理论对指导深部找煤具有重要意义。  相似文献   

5.
A new species of tapejarid pterosaur, Huaxiapterus coroUatus sp. nov. is erected on the basis of a nearly complete skull and postcranial skeleton from the Lower Cretaceous Jiufotang Formation of Liaoning Province, China. Huaxiapterus coroUatus sp. nov. is characterized by a hatchet-shaped rectangular process on the premaxilla, whose short axis is perpendicular to the anterior margin of the premaxillae. Except for this process, other characters of the skull such as the breadth of the snout between the anterior margin of the nasoantorbital fenestra and the anterior margin of the premaxilla are similar to that of Huaxiapterus jii. Huaxiapterus and a second Chinese tapejarid, Sinopterus, share several unique cranial characters in common with Tapejara and these three genera appear to be more closely related to each other than to other azhdarchoids. The Chinese tapejarids (Sinopterus and Huaxiapterus) have relatively elongate skulls and weakly developed cranial crests and seem to be less derived than Tapejara, with its shorter, deeper skull and large cranial crest. Tupuxuarids (Tupuxuara and Thalassodromeus) have often been associated with tapejarids in the family Tapejaridae, but this relationship is controversial because some phylogenetic analyses have supported the pairing of tupuxuarids with Azhdarchidae. We propose that Tapejaridae be restricted to Tapejara, Sinopterus and Huaxiapterus.  相似文献   

6.
Based on the new data of isotopic ages and geochemical analyses, three types of Mesozoic granites have been identified for the Xiong'ershan-Waifangshan region in western Henan Province: high-Ba-Sr I-type granite emplaced in the early stage (~160 Ma), I-type granite in the middle stage (~130 Ma) and anorogenic A-type granite in the late stage (~115 Ma).Geochemical characteristics of the high-Ba-Sr I-type granite suggest that it may have been generated from the thickened lower crust by partial melting with primary residues of amphibole and garnet. Gradual increase of negative Eu anomaly and Sr content variations reflect progressive shallowing of the source regions of these granites from the early to late stage. New 40Ar/39Ar plateau ages of the early-stage Wuzhangshan granite (156.0±1.1 Ma, amphibole) and middle-stage Heyu granite (131.8±0.7 Ma, biotite) are indistinguishable from their SHRIMP U-Pb ages previous published, indicating a rapid uplift and erosion in this region. The representative anorogenic A-type granite, Taishanmiao pluton, was emplaced at ~115 Ma. The evolution of the granites in this region reveals a tectonic regime change from post-collisional to anorogenic between ~160 Ma and ~115 Ma. The genesis of the early- and middle-stage I-type granites could be linked to delamination of subducted lithosphere of the Qinling orogenic belt, while the late-stage A-type granites represent the onset of extension and the end of orogenic process. In fact, along the Qinling -Dabie-Sulu belt, the Mesozoic granitoids in western Henan, Dabieshan and Jiaodong regions are comparable on the basis of these temporal evolutionary stages and their initial 87Sr/86Sr ratios,which may suggest a similar geodynamic process related to the collision between the North China and Yangtze cratons.  相似文献   

7.
Recognized in the Xianghualing region,South Hunan are three major types of granitoids,i.e.,biotite granite,zinnwaldite-albite granite and xianghuagite,which evolved form the same granitic magma,but were formed at different stages.These granitoid rocks constitute a complete magmatic evolutionary series.With the evolution of magma,REE contents and negative Eu anomalies tend to decrease progressively,and LREE become more and more enriched relative to HREE .The facts mentioned above show that the tendency of REE evolution in granitoid rocks in the region studied is different from that in other regions.Evidence indicates that the granitic magma system became more and more depleted in Si(K Na),but richer and richer in Al,Li,F and H2O^ during the process of its evolution,re-sulting in relatively weak acidity and strong alkalinity .It may be the most important factor leading to a specific REE evolutionary trend for the granitoid rocks in this region.In addition,the changing oxidation-reduction environments at different evolutionary stages of this magma system may be anoth-er important factor which should be taken into consideration.  相似文献   

8.
汪洋  姬广义 《地球学报》2007,28(4):324-334
为更好理解燕山带的构造,作者在燕山地区开展了构造填图.在近年的构造填图中于辽宁省绥中县永安堡地区识别出大型的构造窗,其原始的逆掩推覆构造系统上盘由太古宇片麻岩及上覆岩系组成,而下盘由强烈韧性变形的张家口组火山岩系组成.填图结果表明,永安堡地区并不是一个张家口组岩层形成的宽缓向斜,也不是大型古火山机构.燕山地区在早白垩世张家口组火山岩喷发之后仍然存在强烈的区域挤压变形作用.基于野外观察和填图工作,我们认为国内已发表的地质图件未能真实反映燕山带的区域构造基本特征.  相似文献   

9.
A new Early Cretaceous enantiornithine bird from Liaoning Province of northeastern China, Shengjingornis yangi, gen. et sp. nov., is reported. This new bird possesses the following unique combination of features: a long rostrum, with some teeth in the front; short nasal; slender jugal; Y-shaped furcula, with expanded distal end of the hypocleidum; cake-like sternum, with a low and caudally distributed keel; strut-like and caudally concave coracoid. The derived features of the scapula and the wings suggest a powerful flapping flight capability.  相似文献   

10.
Sapeornithidae is a basal pygostylian family of Early Cretaceous primitive birds, in which only one genus and species, Sapeornis chaoyangensis, was reported before. This paper deals with a new genus and species of this family, Didactylornis jii gen. et sp. nov., which was unearthed from the Early Cretaceous Jiufotang Formation in western Liaoning. According to our phylogenetic analyses, both Didactylornis gen. nov. and Sapeornis form a sister group, which is basal to the clade formed by Confuciusornis and all the more derived birds, and more closely related to the short-tailed pygostylian birds than to the long-tailed avialian birds. The early history of pygostylian birds is poorly documented except for the studies of Confuciusornis and Sapeornis. The discovery ofDidactylornisjii gen. et sp. nov. adds the new material for the study on the early evolution of birds.  相似文献   

11.
河南商城汤家坪铝质A型花岗岩位于大别碰撞造山带,岩石组合为正长花岗斑岩、碱长花岗岩。地球化学上,岩石具有富硅(SiO2=72.94~77.90%)、富碱(ALK=7.9—9.66%),铁镁比值较高(FeO^τ/(FeO^τ+MgO)=0.84—0.97),CaO、MgO含量低,富含Zr、Nb、Ce、Ga、稀土元素(REE)、Y等,贫Sr、P、Ti,镓铝比值高(10^4×Ga/A1=3.78~4.36),轻重稀土分馏明显((La/Yb)N=18.12~23.56),中等程度负铕异常(8Eu=0.45~0.51)等特点。在花岗岩成因类型判别图解中,它们均投影在A型花岗岩区域,在微量元素蛛网图上,岩石表现出较明显的Ba、Sr、P、Ti的负异常,保留有先期“弧”岩浆作用的地球化学印记,在微量元素构造环境判别图解中,它们均投影在板内花岗岩区域内,反映其形成于非造山的板内环境,这与它们具有的A型花岗岩性质相一致。根据对岩石地球化学组成及产出地质背景的分析,表明岩体应形成于造山期后的伸展构造背景。  相似文献   

12.
New Tapejarid Pterosaur from Western Liaoning, China   总被引:5,自引:1,他引:5  
A new tapejarid pterosaur Huaxiapterus jii gen. et sp. nov. is erected based on a nearly complete skeleton with a skull. The skull morphology of Huaxiapterus jii gen. et sp. nov. appears transitional between the skulls of Sinopterus and Tapejara. The skull morphology (low crest) of Huaxiapterusjii indicates that Huaxiapterus is more closely related to Sinopterus than to Tapejara, which has a high crest. The relatively long and shallow skull of Sinopterus indicates that it is a primitive form. Huaxiapterus is more derived than Sinopterus but more primitive than Tapejara.  相似文献   

13.
辽西义县组的地质时代   总被引:9,自引:0,他引:9  
长期以来辽西义县组地质时代存在争论。通过对义县组命名地义县上底家沟—砖城子剖面义县组下部玄武岩的定年 ,获得K Ar年龄 131.2± 2 .6Ma ,坪年龄tp130 .4± 1.0Ma ,总气体年龄ttg130 .1± 1.3Ma ,等时年龄tI130 .5± 1.5Ma。这一结果表明 ,辽西义县组的地质时代应属早白垩世 ,其时代可与浙西劳村组、江苏宁芜盆地龙王山组、安徽庐枞盆地砖桥组对比。  相似文献   

14.
新反鸟化石(Gracilornis jiufotangensis gen. et sp. nov.)产于辽宁省朝阳地区早白垩世九佛堂组。根据该反鸟的骨骼细弱、肢骨关节发达、胸骨与躯干相比较小(胸骨宽与躯干长比率约为0.11;胸骨长与躯干长比率约为0.13)等不同于其他已知反鸟的特征,建立一新属种,归于华夏鸟科(Cathayornithidae)。  相似文献   

15.
辽西早白垩世早期热河生物群沉积环境及古地理综合研究   总被引:6,自引:2,他引:6  
巩恩普  梁俊红  李小冬  王春红  崔显德 《地质学报》2007,81(1):1-8,图版Ⅰ-图版Ⅱ
辽西地区早白垩世早期义县组以产出精美的热河生物群而闻名于世,热河生物群研究的每一个重要进展都引起国内外科学家的极大关注。然而热河生物群产出的古地理环境和盆地沉积特征的研究由于受到后期构造破坏和风化作用的影响,难以开展详细的野外工作,研究程度较低。本次系统的野外沉积学工作表明,辽西地区义县组6个沉积层形成于被动大陆边缘向前陆盆地演化过程中的各个阶段,区域沉积环境属于冲积扇-辫状河-曲流河-湖泊沉积体系。从老公沟层到金刚山层经历了沉积环境的频繁变化,岩相类型和岩石组合频繁更替,碎屑供给充分,快速沉积的演化过程,最终完成了盆地充填。全部沉积环境可进一步分为河流和湖泊两大类。河流沉积相在义县组各沉积层的早期占据主体部分,每一盆地构造演化旋回的沉积阶段都是从洪积扇到河流相开始的,并受当时的地质、地理和气候条件的差异分别向淡水湖泊沉积和咸水湖沉积演化。在以河流沉积为主的盆地充填阶段主要由洪(冲)积扇组合、洪泛平原组合和湖岸平原-三角洲组合三种组合模式构成。湖泊沉积主要由静水深湖沉积模式和半咸水湖的(膏盐)碳酸盐沉积模式构成。  相似文献   

16.
This paper describes an avialian bird from the Early Cretaceous Jiufotang Formation in Yixian county, western Liaoning, China, which is named as Shenzhouraptor sinensis by Ji et al. on July 15, 2002. Shenzhouraptor sinensis is characterized by no teeth in its mouth, the forelimbs longer than the hindlimbs, a long tail with more than 23 caudal vertebrae, U-shaped wishbone, and remiges longer than the total length of ulna and manus. It is certain that the new avialian bird is really capable of powerful flight, representing a missing link between theropod dinosaurs and birds.  相似文献   

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