阿中地块南缘晚元古代火山岩地质特征及构造环境分析

阿中地块南缘晚元古代索尔库里群基性火山岩与滨浅海相细粒陆源碎屑岩、成熟度较高的石英砾岩和碳酸盐岩共生,这套火山-沉积岩发生浅变质强变形作用改造,其形成于大陆裂谷构造环境,基性火山岩为大陆裂谷拉斑玄武岩,火山岩-火山碎屑岩上覆岩系--碳酸盐岩中含大量小型叠层石,通过区域对比证明该套地层时代为晚元古代青白口纪,其沉积建造、岩相古地理环境与塔里木北缘库鲁克塔格地区同时代地层特征相似,说明青白口纪时南、北塔里木就有了统一的盖层.     

湘南晚二叠世生物礁钙质海绵古生态特征及造礁机制探讨

湘南晚二叠世生物礁造礁生物主要是钙质海绵．通过野外礁组合露头观察、实测剖面及室内对钙质海绵的系统研究，在讨论造礁海绵的形态、生长发育与藻类的关系后认为：钙质海绵底栖固着生活，适宜在盐度正常，中等动荡循环水流，光照充足，温暖的较远岸的浅水海洋环境．藻类对海绵造礁有重要作用，一方面，从群落生态看。藻类和海绵是互利的，藻类附着在活着的大型海绵上，增强海绵的抗浪性；另一方面，覆盖在死亡、倒伏的海绵上。加固了礁基底，为新一代海绵幼虫提供硬基底，完成海绵原地世代更替，形成独特的藻—海绵造礁机制．     

云南元谋晚中新世真角鹿化石一新种及其古环境探讨

系统记述了在近几年对元谋古猿地点哺乳动物化石的整理研究过程中发现的粗壮真角鹿新种(Euprox robustus sp. nov.). 真角鹿是一类最早的具有进步角的鹿, 新种是在我国发现的第3种真角鹿. 从新种的形态特征推测, 新种的食物主要为浆液较多的双子叶植物的嫩叶, 因此在它所生存的时代元谋盆地的植被为南亚热带常绿阔叶林, 气候环境温暖湿润并有较强的季节性. 这种季节性气候形成的主要原因是季风的影响, 其次才是纬度的作用.     

农作物的主要代表——稻的技术和文化发展

在我国,至今已发现稻作遗址170多处,目前所知世界上最早稻谷遗存是在湖南道县玉蟾岩和江西万年仙人洞.其中,玉蟾岩发现少量稻谷壳,保留部分野生稻特征,属栽培不久籼粳尚未完全分化的古稻,样品年龄为12000～9900 aBP;仙人洞遗址的上层年龄为12000～9000 aBP,有大量栽培稻的植硅石.这些稻作遗存表明,稻是我国最早栽培的作物之一.     

Extinction pattern of reef ecosystems in latest Permian

Studies of two Permian-Triassic boundary (PTB) sections on top of a Changhsingian reef in Ziyun, Guizhou Province, southwestern China indicate that the end-Permian mass extinction of reef ecosystems occurred in two steps. The first step is the extinction of all stenotropic organisms such as calcisponges and fusulinids in the latest Permian (in the Clarkina yini conodont zone). The biota after the first extinction is simple, comprising eurytropic organisms including microgastropods, ostracods, and some small burrowing organisms, or only algal mats. At the beginning of the Early Triassic (i.e. the beginning of the Hindeodus parvus zone), the environments became anoxic, and the microgastropod dominated biota or algal mats disappeared, which constituted the second episode of the mass extinction. The biota after the second extinction comprises small spherical microproblematica, some kinds of specialized organisms tolerant of anoxic or oxygen-poor conditions. As the environments became oxygenated, the specialized biota was replaced by a microgastropod-dominated simple biota. When the environmental conditions improved further, the simple biota was replaced by a diverse biota with normal-sized ammonoids, bivalves, and gastropods, representing restoration of normal oceanic condi- tions. Comparison with PTB sections in Dolomites, Italy and Meishan, Zhejiang Province shows that non-reef ecosystems had a similar first episode of mass extinction in the latest Permian. In the case that oceanic anoxia happened, non-reef ecosystems had a second extinction episode similar to that of reef ecosystems.     

Summer sea-surface temperatures and climate events on the North Icelandic shelf through the last 3000 years

Diatom data from core MD992271 on the North Icelandic shelf record a cooling trend through the last 3000 years. This is indicated by a general decrease in warm water species and an increase in cold water taxa. The relative abundance of these two diatom groups changed periodically, suggesting that the climate also fluctuated within this time period. The results of diatom-based transfer function calculation show that the summer sea-surface temperatures (SSTs) before 1400 cal. a BP were generally higher than the mean value for the last 3000 years and the summer SSTs fluctuated around the mean between 1400 and 700 cal. a BP, and dropped to the values below the mean after 700 cal. a BP. Four cooling events were distinguished, centered at around 2600, 1900, 1300 and 600 cal. a BP respectively. The results are not only consistent with the data from neighbouring cores HM107-03 and MD992275, but also comparable with those from the GISP2 ice core and from other marine sediment records in the North Atlantic. This suggests that changes in the summer SSTs reflect regional climate variations in the North Atlantic. On the North Icelandic shelf, the summer SST variation is a result of changes in the in-teraction between the cold and the warm currents in the area.     

生态条件对籼粳稻杂交后代亚种特性与经济性状的影响

以两个典型的籼粳交重组自交系F6群体(RILSA:中优早8号/丰锦、RILSB:七山占/秋光)为试材,分别在四川和辽宁同年种植,研究亚种特性和经济性状变化规律及其相互关系的结果表明,不同生态条件下籼粳交后代的亚种特性和经济性状都发生了显著的变化.生态条件对程氏指数和构成性状的影响因群体和性状而异,RILSA群体在四川和辽宁都呈偏粳分布,RILSB群体在辽宁接近正态分布,在四川呈偏粳分布,总体上四川表现比辽宁更加偏粳.与辽宁相比,四川穗数、结实率和千粒重降低,因而产量极显著下降,而穗粒数在不同地区和不同群体间差异不显著.程氏指数和构成性状与产量和经济性状有正相关的趋势,据此进行人工选择可能是北方稻区籼粳稻杂交育成品种仍然基本保持粳亚种特性的重要原因.此外,还讨论了籼粳分化与生态条件的关系等相关问题.     

龙潭楔叶的再研究——兼论华南晚泥盆世楔叶目的演化

基于安徽省巢湖市狮子口剖面上泥盆统(法门阶)五通组的标本,对龙潭楔叶Sphenophyllum lungtanense Gothan et Sze的叶形和脉式等重要特征取得了新认识。华南晚泥盆世楔叶目的起源和演化分异模式不同于劳俄大陆的同类植物,它们兼有原始和进化的营养器官(枝状、线状或片状叶)和生殖器官(缺少或具有孢子叶),显示出较高的形态多样性和镶嵌演化。     

贵州关岭三叠系中一奇特的楯齿龙类

记述了产自贵州省关岭县法郎组瓦窑段一豆齿龙类新属种——多板砾甲龟龙（Psephochelys Polyosteoderma gen et sp nov)。标本为完整的头骨、背甲和部分四肢骨骼。砾甲龟龙的头骨综合体现了欧洲Psephoderma和Placochelys两个属的共同特征，而背甲和腹部的结构则完全与众不同。砾甲龟龙的腹部由分布于两则部分的一系列松散的长形骨板和中部的密集的腹肋组成，这种结构是任何其他豆齿龙所不具备的。另外，该标本头骨中部的一些结构十分奇物，目前还很难对其作出确定的解释，这些结构主要涉及鼻骨与前额骨的界限以及额骨、后额骨与顶骨三者间的关系。就目前的标本看，此前从未在豆齿龙亚目（Cyamodontoidea)中被记录过。这些罕见特征的最终确立还有待于更多标本来加以证实。     

北淮阳晚中生代火山岩定年及火山砾石地球化学:对大别灰色片麻岩隆升和中生代地层格架的约束

对北淮阳晚中生代火山岩的野外调查和K－Ar定年结果表明，该区发生过两期火山喷发作用：主要分布于金寨、鲜花岭和毛坦厂地区的原毛坦厂组火山岩，形成于149－138Ma；主要分布于舒城一带的原晓天组火山岩K－Ar年龄为132－116Ma。两者之间为含灰色片麻岩、榴辉岩和火山岩砾石的火山沉积砾岩层。砾岩层内火山砾石的地球化学特征与毛坦厂组火山岩一致，而有别于晓天组火山岩。该砾岩层于138－132Ma堆积而成，暗示135Ma前后北大别灰色片麻岩已从中上地壳折返至地表接受剥蚀，成为北淮阳中生代沉积盆地的重要蚀源区。结合北淮阳地区中生代火山－沉积特征，将该区中生代沉积地层依次划分为防虎山组（＞160Ma)、圆筒山组（三尖铺组中下部，约160－149Ma?)、毛坦厂组（周公山组／三尖铺组上部／凤凰台组，约149－135Ma，顶部为砾岩层）、晓天组（白大畈组／黑石渡组，底部为砾岩层，135－116Ma).