南疆克里雅河绿洲发育和演化过程研究

文章以塔里木盆地中克里雅河绿洲为典型例子，分析现代绿洲发育与演变的证据，并以绿洲沉积物的绝对年龄数据作对照，演绎出绿洲演变的序列与过程，并就影响绿洲演变的三种因素，气候（温度为主）新构造性质和人类活动作出分析，三种因素在不同时期的耦合决定绿洲的性质和发展过程。     

地下河洞穴发育的系统演化

本文运用系统科学理论的某些基本原理和洞穴发育模拟实验研究成果，在我国南方喀斯特区多年研究实践的基础上，把一个地下流域看作一个物质与能量的输入─输出系统。将这一系统的洞穴发育分为流入（输入）洞穴，流出（输出）洞穴和含水层洞穴三大部分。分析和讨论了它们的发育机制、基本特征、相互关系及整体系统有序化的演化过程。     

The Neoproterozoic assembly of Gondwana and its relationship to the Ediacaran–Cambrian radiation

The assembly of the Gondwana supercontinent during the waning stages of the Proterozoic provides a tectonic backdrop for the myriad biological, climatological, tectonic and geochemical changes leading up to, and including, the Cambrian radiation. A polyphase assembly of Gondwana during the East Africa, Brasiliano, Kuungan and Damaran orogenies resulted in an extensive mountain chain which delivered nutrients into a shifting oceanic realm. An analysis of key evolutionary events during this time period reveals the following (a) several fauna show well established endemism that may be rooted in a cryptic evolutionary pulse (c). 580 Ma (b) the margins of the Mirovian and Mawson Oceans formed the locus of radiation for the Ediacaran fauna (c) the margins of the Iapetan and Mirovian oceans form the olenellid trilobite realm (d) the margins of the Mawson and Paleo-Asian oceans are the birthplace of the so-called Gondwana Province fauna (e) evolutionary events associated with the Cambrian radiation were likely driven by internal (biological) changes, but radiation was enhanced and ecosystems became more complex because of the geochemical, ecological and tectonic changes occurring during Ediacaran–Cambrian periods.     

New data on the zoogeography of Aphanius sophiae (Teleostei: Cyprinodontidae) in the Central Zagros (Southwest Iran)

The clade of the Iranian freshwater Aphanius species from endorheic and exorheic drainage basins contains three subclades, of which the Aphanius sophiae subclade with seven species is the most specious one. Recently, two previously not known populations of Aphanius were discovered in two isolated basins; one in the Arjan Wetland (Helleh subbasin), and the other in the Semirom spring (Karun Basin), both are located in the Central Zagros Mountains (SW Iran). The objective of this study is to investigate their taxonomic status, to elucidate their phylogenetic relationships and to contribute to future conservation strategies and habitat management of the freshwater species of Aphanius in Iran. Methods include analysis of genetic data based on mtDNA (cyt b), combined with meristics, morphometrics, scale sizes (J-indices) and otolith data. The results based on cyt b clearly indicate that two species are present in the Arjan Wetland, one is closely related to A. sophiae (currently thought to be restricted to the Kor Basin), the other represents Aphanius shirini (previously only known from its type locality Paselari spring). However, significant phenotypic differences are not present between these two species. The second population from the Semirom spring is sister to A. sophiae (Kor Basin) according to cyt b data, but differs significantly from this species with regard to the phenotype. The presence of A. shirini in the Arjan Wetland is most likely be explained by man-made introduction because of the recent droughts. The similarity of the two species present in the Arjan Wetland may be due to phenotypic plasticity, but also hybridization could have played a role. The isolation of populations of A. sophiae is discussed in the context of the active geological history and climate change, and it is likely that their divergence happened in the Early or Middle Holocene (c. 11,700–4000 y. ago). The presence of A. sophiae in the Helleh subbasin and Karun Basin extends the currently known zoogeographic range of this species, which previously has only been reported from the Kor Basin. Such knowledge is important for future conservation strategies and habitat management.     

印支运动以来中国海陆地势演化及阶梯地貌特征

地势是地面高低起伏的形势,是地球内营力和外营力共同作用的结果,是地壳内部结构、构造及其发展在地表的反映.空间重力异常与地形、地貌密切相关,反映地壳内部结构和构造的变化.均衡原理认为高山下面地壳厚,平原下面地壳薄,即地势的起伏同莫霍面的起伏呈镜像关系.中国海陆地质地球物理系列图编制了大地构造格架图和大地构造格架演化图等专题图件,对中国海陆各主要块体的时空演化进行研究,研究了中国海陆地势的"跷跷板"演化过程.本文根据中国海陆1:500万空间重力异常图和莫霍面深度图分析了海陆地貌特征,按照构造地貌的分类原则,将中国海域和陆域作为一个整体进行地貌分类,在中国大陆地势呈三个地貌阶梯的基础上,总结出中国海陆地貌总体特征为西高东低,呈五级阶梯分布.     

龙木错地区泽错岩体演化历史及构造意义:来自地球化学和年代学的约束

沿大型断裂带出露的深成岩体记录并保存了形成时的大地构造活动及后期演化和变形的重要信息。为了更好地理解羌塘西部花岗岩的成因机制和演化历史,本文选取了龙木错断裂南部的泽错岩体进行地球化学、SHRIMP锆石U-Pb年代学及云母和钾长石~(40)Ar/~(39)热年代学分析。全岩地球化学判别图显示花岗岩样品为高钾钙碱性系列至钙碱性系列和过铝质。矿物组合表明无角闪石且含白云母。以上特征均显示出明显的S型花岗岩趋势。锆石U-Pb年龄为123±1. 7Ma至107±1. 4Ma,表明岩浆侵位的时代为早白垩世,此时班公-怒江洋仍在向北俯冲。云母和钾长石~(40)Ar/~(39)年龄及前人低温热年代学数据显示,侵位后岩体至少有四个阶段的冷却,包括120～90Ma、90～38Ma、38～26Ma和26～0Ma。第一阶段在侵位后10Myr内快速冷却至低于～320℃,而随后以相对较慢的速率冷却至～220℃。从90Ma到38Ma期间经历了较长时期极为缓慢的冷却,该阶段构造活动趋于静止,表明羌塘地体-拉萨地体碰撞应发生在90Ma之前。中新世受控于龙木错断裂左旋走滑的影响,最后一期的构造变形以东西向伸展为主,深成岩逐渐剥露至地表。龙木错断裂可能作为中新世以来高原物质向东运移西部边界的一条新的应力释放途径。     

水库诱发地震时空演化与库水加卸载及渗透过程的关系 ——以紫坪铺水库为例

为了解水库蓄水过程中,水库诱发地震活动的动态响应机制,本文建立了针对水库诱发地震(Reservoir-induced seismicity,RIS)定量化研究的数理模型,并以紫坪铺水库为例,对库区地质构造及水文地质结构条件、水库蓄水后库区小震活动时空演化特征进行了详细的研究.在此基础上,利用有限元方法计算了水库蓄水过程中弹性附加应力场、有效附加应力场、孔隙压力和断层稳定性的动态变化,讨论了RIS时空演化与库水加卸载及渗透过程的动态响应关系.结果表明:(1) RIS诱发机制的定量化模型可分为2个层次:一是以孔隙介质为载体的流体渗流对岩体变形和稳定性的影响,由流-固耦合形式的岩体变形与孔隙渗流模型进行描述;二是对断层相关的RIS定量研究可将水库附加水头压力沿断层面(区)的扩散与断层库仑应力变化联系起来.两种形式模型方法的结合能为RIS定量研究提供一个相对宏观的力学框架;(2) 断裂渗透结构对孔隙压力变化下断裂的力学响应具有重要的影响,研究区主干断裂可能属于一种上盘破碎带导水、下盘地层及断层核阻水的"下阻上导型"的渗透结构类型,不同程度的具有使地表水体向深部渗流的通道性.库区深部岩体渗透稳定性的差异在很大程度上导致了诱发地震活动对岩性条件的依赖.(3) 紫坪铺水库蓄水后,小震活动在空间分布上呈现出条带状分布、丛集分布和地震迁移的特点,小震震源深度优势分布在地下4~10 km范围内,在通济场断裂与安县-灌县断裂的深部汇聚区域震源分布最为密集.同时,小震活动主要集中发生在脆性程度高、渗透稳定性低的碳酸盐岩地层中,而在岩性较软弱、渗透稳定性高的三叠系须家河组砂泥岩和煤系地层中很少有地震发生.在水库蓄水后地震活动的时间响应特征上,水库西南侧和东北侧两个丛集区的小震活动可能属于"快速响应型"RIS,而都江堰小震群活动可能属于"滞后响应型"诱发地震活动;(4) RIS的发生与库水加卸载及渗透过程中库底岩体有效应力的变化密切相关.在以挤压为主的构造应力环境中,库体荷载作用的结果一般会使库底断层更趋向稳定,而水库附加水头压力扩散的效应则是促使断层趋向失稳,正是这个矛盾双方相互制约与平衡的动态过程,控制了断层库仑应力变化的取向,从而决定了RIS时空演化的规律.     

A tooth of Archaeopterygidae (Aves) from the Lower Cretaceous of France extends the spatial and temporal occurrence of the earliest birds

The Late Jurassic Archaeopterygidae, comprising the iconic genus Archaeopteryx, is altogether among the earliest, basalmost and best-known Mesozoic avian taxa. The geographic distribution of Archaeopteryx is hitherto restricted to a limited region of southern Germany, probably due to preservation biases. Here we describe a tooth sorted among the more than 35,000 isolated teeth found by sieving sediments from the Cherves-de-Cognac locality (western France, Lower Cretaceous). This tooth crown is morphologically similar to teeth of the German specimens of Archaeopteryx (sensu lato), despite minor differences. The Cherves-de-Cognac tooth differs much more importantly from all other known taxa. It shares with different specimens of Archaeopteryx the general tooth size, recurved shape affecting apical third of crown, thin apical-mesial carina, constriction at base of crown giving distinctive S shape of distal edge in profile, absence of other ornamentation or serration, and shape of crown section. Incidentally, former assignments of teeth from the Upper Jurassic of Guimarota (Portugal) to cf. Archaeopteryx are unwarranted, as those teeth markedly differ from the Archaeopterygidae in several crucial features. We assign the new tooth to the family Archaeopterygidae, the earliest European birds, making it the first member of the family in Europe outside Germany, and extending its temporal occurrence to the early Cretaceous.     

Origin and evolutionary history of Anglonautilus (Nautilida,Cymatoceratidae) and a new species from the lower Aptian of Spain

The cymatoceratid nautilid genus Anglonautilus is distinguished from most other post-Triassic nautiloids by the occurrence of pronounced fold-like undulating ribs on the phragmocone and early body chamber. Anglonautilus praeundulatus n. sp. is described from the lower Aptian of eastern Spain. It is the first record of this genus from Spain and constitutes the oldest definite representative of the genus. This places the new species at the base of the evolutionary history of Anglonautilus. Its ornamental features confirm the previously assumed close relationship between Anglonautilus and Cymatoceras. An analysis of the ornamental pattern of all species hitherto referred to Anglonautilus indicates that there is an evolutionary lineage leading to the type species of the genus, A. undulatus, and a single successor (A. subalbensis). Several Late Cretaceous species hitherto identified as Anglonautilus (A. japonicus, A. mamiyai, A. suciensis) bear fold-like ribs superficially similar to typical representatives of Anglonautilus. The pattern of ornament in these taxa is very different at closer inspection, though. This suggests that these species developed independently from Cymatoceras. The undulations present in these taxa are interpreted here as a result of convergent evolution. They are therefore excluded from the genus Anglonautilus and provisionally referred to as “Anglonautilus” spp.     

基于RS技术的北江下游河道岸滩演变分析

以1975～2001年共7个时相的遥感影像作为数据源,在GIS支持下采用动态分析方法,对比各个时期北江下游河道岸滩形态及位置变化,结合河道的地质、地貌、水文泥沙、整治工程等信息,分析洲滩消长的原因,获取河道横向演变特性,预测岸滩变化趋势以及整治工程效果.对比该时段内北江下游河道纵向演变情况,得出河道的纵向变形影响横向变形,总体变化两者成反比关系,河势向着稳定的趋势发展.