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1.
广东乐昌第四纪大熊猫-剑齿象动物群计有5目15属16种,主要属种有大熊猫洞穴亚种、东方剑齿象、中国犀、中国黑熊、水鹿和水牛等,这些都是南方大熊猫-剑齿象动物群的典型分子,与曲江马坝动物群、封开黄岩洞动物群比较接近,时代为中更新世末期或晚更新世早期.动物群反映的当时的生态环境除了森林比较茂密外,水草也比较丰富,气候温凉而不很干燥.该动物群是广东粤北地区继曲江马坝动物群、罗坑动物群以及灵溪暗岩动物群之后又一重要发现,对研究华南地区第四纪动物群的分布、变迁以及当时的古气候和古环境等具有一定意义.  相似文献   

2.
以山羊寨动物群中的食虫类为研究基础,讨论了中国Erinaceus,Sorex,Crocidura,Scaptochirus和Neomys5属食虫类更新世以来在中国的时空分布变化,并与相关现生属种的地理分布进行比较,结合现代动物地理、动物生态资料进行分析。研究表明,中国北方更新世以来的环境变化具有暖干化趋势。  相似文献   

3.
珠江三角洲是世界上主要河口三角洲之一,自晚更新世开始形成,其沉积物中保存了丰富的微体动物壳体,它们是重建晚第四纪古环境极为有效的指标。本文对珠江三角洲东部PRD17孔的微体动物群(有孔虫和介形类)进行了分析,共发现有孔虫14属29种,介形类14属17种,将其分别划分为3种生态类型。根据微体动物群的组成特征,并结合测年数据、岩性、沉积物粒度及颜色反射率等特征,重建了PRD17孔晚第四纪以来的环境演化。约43 400 cal a B.P.以前,钻孔所在地发育河流相沉积。晚更新世玉木亚间冰期开始,南海海平面回升,本区开始形成第四纪以来的第一个海相层位。从微体动物群的组成和丰度可识别出3次小规模的海平面波动。约35 400~30 900 cal a B.P.为晚更新世最大海侵时期,微体动物群的丰度和分异度都达到峰值。约25 900 cal a B.P.以后,海水逐渐退出。末次冰盛期的海平面大幅下降,导致本区上更新统沉积物暴露地表遭受风化剥蚀,形成珠江三角洲普遍发育的花斑状黏土层。由于钻孔所在地地势相对较高,受全新世海侵的影响较珠江三角洲其它地区晚,直到6 000 cal a B.P.左右才重新接受沉积,初期发育上潮间带沉积。约3 700 cal a B.P.开始,逐渐变为受潮水影响较显著的潮坪环境。  相似文献   

4.
临夏盆地位于甘肃省东南部,是青藏高原东北缘的一个山前凹陷盆地。其晚新生代地层非常发育,蕴藏着丰富的哺乳动物化石。中国科学院古脊椎动物与古人类研究所已在临夏盆地从晚渐新世至早更新世的各个层位中,发现和征集了大量的哺乳动物化石,其中以距今1500~1200万年的中中新世铲齿象动物群、1000~700万年的晚中新世三趾马动物群和约200万年的早更新世真马动物群的材料和种类最为丰富。已有的化石标本产自近50个化石地点,约1700多件哺乳动物头骨,以及大量牙齿和肢骨,代表了100多种哺乳动物;另有陆龟化石…  相似文献   

5.
甘肃环县楼房子晚更新世孢粉组合   总被引:6,自引:0,他引:6  
一九六三年初夏,我系黄土科研组,在环县楼房子附近,环河一级支流合道川柏林沟二级阶地沉积物中,发现了丰富的哺乳动物化石,经薜祥煦同志鉴定有:披毛犀(Coelodonta antiguitatis)、赤鹿(Cervus elaphus)、原始牛(Bos primigenius)、盘羊(Ovis ammon)等喜寒动物群。这个动物辟除缺象类化石外,其余与萨拉乌苏动物群相同,时代当属晚更新世。孢粉取样直接来自埋藏该动物群的剖面中。本文试图通过孢粉分析,了解当时的植被,再现古气候、古地理,不但具有一定的科学价值,也是寻找各种沉积矿产的一种值得注意的方法。  相似文献   

6.
赵店动物是作者近年来的一个新发现,本文对赵店动物群的化石类型,沉积特征、生态环境和地层时代等进行了初步研究,提出这一动物群生态于中更新世晚期(相当于大洋氧同位素阶段6)。赵店动物群的发现对研究这一时期生物演化及环境变化具有重要价值。  相似文献   

7.
重庆合川三汇坝晚更新世哺乳动物群   总被引:1,自引:1,他引:1  
对三汇坝牛尾洞发现的19种哺乳动物化石应用数理统计分析、铀系和含氟量测年分析、孢粉分析进行了研究.论证了它们是一个晚更新世时生活于亚热带暖热湿润气候中的乔木林-灌木林-湿草地动物群.通过它与四川盆地第四纪的几个典型动物群相比较,证明其性质仍是我国南方广义“大熊猫-剑齿象动物群”之一员.其特点鲜明,是该动物群演化发展过程中的一环,介于歌乐山与资阳两动物群之间.  相似文献   

8.
中国梅花鹿地理分布的变迁   总被引:6,自引:0,他引:6  
在综合化石记录、历史文献和野外资料的基础上对我国梅花鹿地理分布的变迁进行了探讨.早更新世,梅花鹿分布于华北区和台湾;中更新世至全新世,向北扩展到蒙新区的东部、东北区以及朝鲜、苏联西伯利亚东南部,向南经华中区的东部分布到广西和越南北部,另有一支经东部滨海平原迁移到了日本.川西高原的四川亚种是由华北区向西南延伸的一支演化而来.梅花鹿是适应性很强的林缘动物,其分布区急剧地缩减与晚更新世至全新世青藏高原的强烈抬升有关,更主要地是受冰期后人为活动的影响.  相似文献   

9.
山东蕨类植物区系   总被引:2,自引:0,他引:2  
山东蕨类植物有24科、39属、96种和9变种,以鳞毛蕨科、蹄盖蕨科、水龙骨科和鳞毛蕨属、卷柏属、铁角蕨属、蹄盖蕨属为优势科属、区系成分以东亚分布为主,达45种,占全部种类的42.9%,其中中国-日本成分35种,占33.3%;其次为中国有成分和山东特有成分,在起源上具古老性,并与热带区系有密切的关系;山东蕨类区系成分在早第三纪时已基本形成。  相似文献   

10.
江西武宁晚寒武世晚期三叶虫   总被引:1,自引:0,他引:1  
本文记述了江西武宁晚寒武世晚期三叶虫9科、11属、3亚属、20种,其中新种4个,未定种6个。从三叶虫组合特征分析可与东南区系江南—西北亚区上寒武统上部西阳山组的标准地区三叶虫动物群对比。对该区寒武纪三叶虫的研究,不仅丰富了寒武纪三叶虫资料,而且为进一步研究江南区寒武纪时的古地理范围,古生物分布特征,地层划分与对比以及对本区寒武系与奥陶系之间分界的研究,提供可靠依据。本文还就本区的晚寒武世地层和三叶虫动物群特征,与邻近地区作了对比和简要的讨论。  相似文献   

11.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

12.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

13.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

14.
Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to  相似文献   

15.
Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications (up to 574.8 km/ h test speeds or 380 km/h commercial speeds) in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.  相似文献   

16.
17.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

18.
Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.  相似文献   

19.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

20.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

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