台西南盆地岩石圈伸展及裂后沉降特征分析

计算有效弹性厚度和不同尺度的拉张因子,并结合裂后的沉积记录可以反映一个伸展性盆地的形成演化特征.运用基于弹性梁模型和挠曲均衡原理的二维构造模拟软件重点对横穿台西南盆地的一条地震地质剖面进行模拟.分析结果表明:1.5km为台西南盆地最合适的有效弹性厚度;岩石圈尺度的拉张因子在1.2～4.8之间,上地壳尺度的拉张因子在1.0～1.2之间,全地壳尺度的拉张因子在1.1～3.0之间,岩石圈伸展具有横向的非均质性和深度的依赖性;台西南盆地裂后阶段受陆架坡折形成、东沙运动两期构造运动影响较大,不同于典型伸展性盆地裂后沉降模式,沉降特征无明显规律性.     

断陷盆地不整合结构定量预测地质模型

探讨地层不整合结构的定量预测问题.通过对济阳拗陷古近系不整合发育特征的研究,将不整合结构划分为3种类型,并进一步明确了不整合结构发育的4种主要控制因素;综合地质和岩心分析测试研究成果,应用模糊判识的方法,确定了评价因素集、权重因素集和隶属函数,建立了用于表征不整合结构特征的模糊识别模型;结合样品分析测试结果,确定了地质模型定量预测不整合结构类型的评价标准.研究表明,断陷盆地不整合结构定量预测地质模型具有较好的适用性.     

辽吉裂谷沉积建造特征分析

为了对辽吉裂谷沉积建造特征认识,结合吉南地区的资料将辽吉裂谷划分为三套沉积建造:早期(下部)陆源砂泥质—火山碎屑岩建造;中期(中部)碳酸盐建造和晚期(上部)碎屑岩,建造清楚地反映了辽吉裂谷从拉张断陷快速沉降到慢速沉降直至消亡收缩的从海进至海退的整个大的沉积旋回的演变过程。这一理论在辽吉裂谷寻找矿具有广泛重要意义。     

安宁河裂谷的“活化”

安宁河裂谷位于"攀西裂谷"的中轴部位,近期研究发现,裂谷区有显著的地壳引张作用,存在地幔隆起与热对流。通过野外实地调查,结合地球物理、断裂、沉积、地震、地应力和地形变等资料,认为安宁河裂谷区现在正处于明显的构造活化状态。这种活化受上地壳塑性流动产生的水平挤压和地幔隆起产生的应力张量的共同作用。据此提出一个新的裂谷活化地壳力源模型,认为在研究区特定的地球动力环境下,以安宁河裂谷为中心,再现岩浆活动和地壳裂陷并非不可能。     

Lithospheric thermal-rheological structures of the continental margin in the northern South China Sea

Thermal structures of three deep seismic profiles in the continental margin in the northern South China Sea are calculated, their "thermal" lithospheric thicknesses are evaluated based on the basalt dry solidus, and their rheological structures are evaluated with linear frictional failure criterion and power-law creep equation. "Thermal" lithosphere is about 90 km in thickness in shelf area, and thins toward the slope, lowers to 60-65 km in the lower slope, ocean crust and Xisha Trough. In the mid-west of the studied area, the lithospheric rheological structure in shelf area and Xisha Islands is of four layers: brittle, ductile, brittle and ductile. Because of uprising of heat mantle and thinning of crust and lithosphere in Xisha Trough, the bottom of the upper brittle layer is only buried at 16 km. In the eastern area, the bottom of the upper brittle layer in the north is buried at 20 km or so, while in lower slope and ocean crust, the rheological structure is of two layers of brittle and ductile, and crust and uppermost mantle form one whole brittle layer whose bottom is buried at 30-32 km. Analyses show that the characteristics of rheological structure accord with the seismic result observed. The character of rheological stratification implies that before the extension of the continent margin, there likely was a ductile layer in mid-lower crust. The influence of the existence of ductile layer to the evolution of the continent margin and the different extensions of ductile layer and brittle layer should not be overlooked. Its thickness, depth and extent in influencing continent margin's extension and evolution should be well evaluated in building a dynamic model for the area.     

浅谈砖砌体裂缝的成因及防治措施

砖砌体因整体性较差,极易产生裂缝。本文针对砖砌体裂缝的产生原因进行了分析,并提出了一些防治措施,供设计、监理、施工人员参考。     

混凝土裂缝产生的原因及预防对策

在工业与民用建筑中,混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题．对混凝土工程中常见的一些裂缝问题进行了探讨分析,并提出了一些预防对策．     

里约奥运会世界体坛实力版图研究

通过文献资料法、数理统计法等方法对里约奥运会奖牌分布情况分析发现:世界体坛实力版图美国一枝独秀,英国金牌榜排名超过中国跃居第二。第二集团保持稳定发展态势,排名略有变化;第三集团整体竞技实力明显提升;奖牌分布不均衡性日趋突出,欧洲依然是世界体坛最强版块,亚洲竞技实力虽有所下滑但仍位于第二位,北美洲竞技实力持续上升,进一步缩小与亚洲的差距,位列第三,南美洲提升幅度明显,非洲实力下滑,大洋洲略有上升。     

Magma-maintained rift segmentation at continental rupture in the 2005 Afar dyking episode

Seafloor spreading centres show a regular along-axis segmentation thought to be produced by a segmented magma supply in the passively upwelling mantle. On the other hand, continental rifts are segmented by large offset normal faults, and many lack magmatism. It is unclear how, when and where the ubiquitous segmented melt zones are emplaced during the continental rupture process. Between 14 September and 4 October 2005, 163 earthquakes (magnitudes greater than 3.9) and a volcanic eruption occurred within the approximately 60-km-long Dabbahu magmatic segment of the Afar rift, a nascent seafloor spreading centre in stretched continental lithosphere. Here we present a three-dimensional deformation field for the Dabbahu rifting episode derived from satellite radar data, which shows that the entire segment ruptured, making it the largest to have occurred on land in the era of satellite geodesy. Simple elastic modelling shows that the magmatic segment opened by up to 8 m, yet seismic rupture can account for only 8 per cent of the observed deformation. Magma was injected along a dyke between depths of 2 and 9 km, corresponding to a total intrusion volume of approximately 2.5 km3. Much of the magma appears to have originated from shallow chambers beneath Dabbahu and Gabho volcanoes at the northern end of the segment, where an explosive fissural eruption occurred on 26 September 2005. Although comparable in magnitude to the ten year (1975-84) Krafla events in Iceland, seismic data suggest that most of the Dabbahu dyke intrusion occurred in less than a week. Thus, magma intrusion via dyking, rather than segmented normal faulting, maintains and probably initiated the along-axis segmentation along this sector of the Nubia-Arabia plate boundary.     

大体积混凝土裂缝成因及预防措施

混凝土在浇筑过程中出现裂缝是极其普遍的现象,然而大体积混凝出现裂缝更为普遍。施工中混凝土出现裂缝,会影响到建筑物的整体性和耐久性,本文对混凝土施工裂缝产生的原因和预防裂缝的措施等进行阐述。     

松辽盆地长岭断陷火山岩储层特征

松辽盆地南部长岭断陷火山岩储层主要发育于下白垩统营城组,在火石岭组部分发育.通过对钻井岩心样品的观察研究,确认储集空间主要有孔隙和裂缝两大类,孔缝组合类型有:孔隙型、裂缝孔隙型、孔隙裂缝型和裂缝型.实测的储层孔隙度为0.14%～26.00%,渗透率为(0.01～79.30)×10-3 μm2,表明储层物性相差大、非均质性强.从压汞曲线数据获得的孔隙度为2%～10%,渗透率为(0.06～0.26)×10-3 μm2,表现为中低孔、特低渗储层.原地火山角砾岩为物性最好的火山岩储层,其次是凝灰岩和流纹岩.     

中国东部新生代陆相断陷盆地层序的构成样式

选取我国东部跨不同古构造、古气候和古地理单元的多个陆相断陷盆地,如济阳凹陷、南阳和泌阳凹陷、南堡凹陷、歧口凹陷、江汉盆地、东濮凹陷、百色盆地和苏北盆地等,以层序界面和层序单元的精细划分为基础,对古近系-新近系的构造地层格架和层序结构特征进行对比分析,总结出犁式断坳型和陡倾式断坳型2种类型层序地层格架和断坡带型、弯折带型、枢纽带型(或斜坡型)3种典型的层序构成样式。不同级次的构造控制着层序的发育和层序样式特点,在此基础上建立了对储集体展布和烃源岩潜力具有重要预测功能的层序地层模式,从而为我国东部具有地域及地质特色的陆相含油气盆地内隐蔽油气藏的寻找和评价提供了一套新的思维框架。     

华北克拉通北缘早白垩世岩石圈减薄: 钾玄岩的Pb同位素证据

内蒙古四子王旗地区出露的早白垩世玄武岩属于钾玄岩。岩石富集大离子亲石元素（LILE）、轻稀土元素（LREE）,亏损高场强元素（HFSE）,其地球化学特征总体与洋岛玄武岩(OIB)相似。w(Rb)/w(Nb)、w(K)/w(Nb)、w(Zr)/w(Nb)、w(Th)/w(Nb)和w(Th)/w(La)比值主要落在EM1-OIB范围内。w(²⁰⁶Pb)/w(²⁰⁴Pb)、w(²⁰⁷Pb)/w(²⁰⁴Pb)和w(²⁰⁸Pb)/w(²⁰⁴Pb)分别变化在17.18～17.81, 15.40～15.50和37.54～38.05之间,岩石的Pb同位素组成接近EM1型地幔端元。随着Pb含量(质量分数)的增加,Pb同位素比值几乎没有变化,表明四子王旗钾玄岩没有经历明显的地壳物质混染。钾玄质母岩浆源于软流圈地幔的减压低度部分熔融。四子王旗钾玄岩是华北克拉通岩石圈减薄事件的产物。     

新疆北山晚古生代克拉通裂谷火山作用特征

新疆北山构造带克拉通裂谷活动期火山活动频繁,火山作用较强烈.区内晚古生代火山岩分布广泛,集中发育于下石炭统上部、上石炭统和下二叠统,与正常沉积岩呈断续间互层状产出.据岩石地层研究、火山岩产状及接触关系,划分为4个火山旋回,共9个火山喷溢韵律.在对区内火山岩地质特征、岩石类型、岩石化学和稀土元素地球化学特征研究基础上,探讨了火山岩的演化特点和形成环境.     

羌塘晚三叠世-早白垩世裂陷盆地基底构造

探讨羌塘盆地基底构造,为油气远景评价提供依据.通过对十多年来积累的地质、地球物理资料和物性资料的研究,在羌塘盆地识别出2个基底界面,一是前寒武系结晶基底顶面的密度(重力异常)界面,二是上三叠统顶部的磁性(航磁异常)界面.根据最新的航磁异常资料,对晓三叠世-早白垩世被动大陆边缘裂陷-拗陷盆地的基底构造单元进行分析,划分出2个Ⅰ级构造单元,4个Ⅱ级构造单元,23个Ⅲ级构造单元.在此基础上识别出3个裂陷槽、2个隆起带,圈定出3个相对应的生烃凹陷,2个发育礁、滩相碳酸盐岩储集层的隆起带,圈定了3个油气运移集聚的远景区.     

Geology and palaeontology of the Late Miocene Middle Awash valley, Afar rift, Ethiopia.

The Middle Awash study area of Ethiopia's Afar rift has yielded abundant vertebrate fossils (approximately 10,000), including several hominid taxa. The study area contains a long sedimentary record spanning Late Miocene (5.3-11.2 Myr ago) to Holocene times. Exposed in a unique tectonic and volcanic transition zone between the main Ethiopian rift (MER) and the Afar rift, sediments along the western Afar rift margin in the Middle Awash provide a unique window on the Late Miocene of Ethiopia. These deposits have now yielded the earliest hominids, described in an accompanying paper and dated here to between 5.54 and 5.77 Myr. These geological and palaeobiological data from the Middle Awash provide fresh perspectives on hominid origins and early evolution. Here we show that these earliest hominids derive from relatively wet and wooded environments that were modulated by tectonic, volcanic, climatic and geomorphic processes. A similar wooded habitat also has been suggested for the 6.0 Myr hominoid fossils recently recovered from Lukeino, Kenya. These findings require fundamental reassessment of models that invoke a significant role for global climatic change and/or savannah habitat in the origin of hominids.     

里约奥运会女子20km竞走运动员战术节奏研究

运用文献资料法、比较分析法、数理统计及观看录像等研究方法,对里约奥运会女子20 km竞走比赛中个人最好成绩或赛季最好成绩在1:29:00以内的17名运动员的战术节奏进行研究。研究发现:17名运动员整体竞技水平没有表现出来;前8名运动员在各区段速度节奏变换的方式及速度存在差异,后半程差异明显,全程速度节奏均以积极节奏为主,采用适合个人竞技特点的速度节奏对竞走比赛结果有着重要的影响;冠军刘虹全程速度变化幅度及离散程度最大,第8名最小,速度变化的幅度及离散程度与名次成负相关;17名选手比赛中位置变化存在交替、前移或后退状态,交替型位置节奏更利于"团队协作",为众多选手所采用。