四川盆地晚二叠世沉积作用的比较沉积学分析

晚二叠世时,中国南方为一多岛环绕的受限陆表海。盆内多为深水谷道分割的碳酸盐台地。在四川盆地内,晚二叠世沉积物可以分为四种基本组合类型,均为同时异性相。 晚二叠世硅质岩为上升洋流沉积。上升流带来大量有机质,有利于生物礁的生长。生物礁主要分布在碳酸盐台地边缘接近上升流的一侧,华南晚二叠世沉积作用受海平面变化引起的峡口启闭作用控制。     

深水储层的地质特征

勘探和研究表明，在世界许多地区，深水大陆边缘具有极好的远景区、可能发现和开发大规模的油气藏。亚洲和太平洋边缘带发育很好的深水远景区带，南海的几个地区正在成为勘探热点。     

Meiofauna as descriptor of tourism-induced changes at sandy beaches

Tourism has long been considered as a 'clean industry' with almost no negative effects on the environment. This study demonstrated, in two different coastal systems (Mediterranean and Baltic), that tourism related activities are particularly affecting the sandy beach meio- and nematofauna in the upper beach zone, the specific ecotone in which many meiofauna species from both the marine and the terrestrial environment congregate. Tourist upper beaches are characterized by a lower % total organic matter (%TOM), lower densities, lower diversities (absence of Insecta, Harpacticoida, Oligochaeta, terrestrial nematodes and marine Ironidae nematodes) and higher community stress compared to nearby non-tourist locations. The %TOM was found to be the single most important factor for the observed differences in meiofauna assemblage structure at tourist versus non-tourist beaches in both the Mediterranean and the Baltic region. The free-living nematode assemblages from tourist upper zones depart significantly from expectations based on random selections from the regional nematode species pool. Furthermore upper zone assemblages are characterised by a low species diversity consisting of taxonomically closely related nematode species with r-strategist features. Generally, faunal differences between tourist and non-tourist beaches are decreasing towards the lower beach zones.     

现代黄河三角洲的结构、发展过程和形成模式

对现代黄河三角洲典型河道－钓口流路的不同钻孔剖面分析，阐明现代黄河三角洲单个流路所形成的三角洲叶片体的沉积物与沉积相的空间分布特征。结合单流路河道的小循环演化规律，划分现代黄河三角洲的发育过程为四个阶段，提出了三角洲的河口坝沉积相间分布的横向沉积序列、主河道型与同汊口河道型两个不同的纵向沉积序列及河口坝型与口坝侧湾型两个不同的垂向沉积序列。在此基础上，提出了现代黄河三角洲的形成模式。     

长江三角洲地区晚第四纪古土壤中的植物硅酸体及其古环…

长江三角洲地区晚第四纪古土壤层，即以前所谓的“暗绿色硬粘土层”过去被看作是“哑地层”，本文首次发现该层中含有丰富的植物硅酸体，且各种类型的硅酸体在地层中均有出现，并在剖面上有较大的变化。在定量统计分析的基础上，利用其组合特征，并进一步利用对应分析方法，探讨了本区晚第四纪古地理、古环境变迁历史，认为该层形成于一种弱草甸环境，且在其形成过程中有四次气候冷－暖变化。     

Spain. Regional differences in population density in 1986: the end of a process of increasing internal disequilibrium?

This is an analysis of regional differences in population trends in Spain during the twentieth century. Data are from a variety of official sources, including the censuses of 1900, 1960, 1970, and 1981. The author notes that up until 1975, interregional migration flows had acccentuated regional economic differences. However, the economic problems that have occurred since 1975, coupled with the political changes associated with greater regional autonomy, have resulted in new trends in internal migration that could have significant effects on the future distribution of the country's population.     

基于Hoek-Brown准则的节理岩体能量参数估算

岩体变形和破坏可以看作能量耗散和释放的过程.由于节理岩体结构复杂且难以开展室内试验,因此无法通过试验直接求取其能量学参数.基于Hoek-Brown准则和岩石能量理论,提出了节理岩体在临界状态能量学参数的估算方法.针对含贯通节理(或层面)岩体,通过修正岩块单轴抗压强度以体现贯通节理的方向效应.采用PFC3D分别模拟小尺寸岩样(Φ50mm×100mm)和大尺寸岩体(Φ2m×2m)的三轴压缩试验,通过岩石三轴试验结果拟合岩石数值模拟的细观参数并应用于节理岩体的模拟.根据节理岩体模拟得到应力应变曲线和能量流,验证了Hoek-Brown准则对节理岩体能量参数估算的合理性.