太古宙陆壳的地质和地球化学演化

引言因为现代大陆壳的大部分(可能大于50％)看来是在太古宙(>25亿年)期间形成的,所以试图认识导致太古宙地壳发展的岩浆和构造作用是重要的。但还存在许多问题。为什么在大约38亿年以前没有形成地壳?或是它再循环回到地幔系统,以致没有残留物吗?太古宙高级片麻岩、麻粒岩区和低级花岗岩一绿岩区之间的主要差别是什么?它们是否代表太古宙不同的构造环境?这种环境是太古宙独有的,或已发现了现代的相     

PCB-containing paint and plaster caused extreme PCB-concentrations in biota from the Sørfjord (Western Norway)--a case study

The Sørfjord (Western Norway) has a long history of industry and pollution, and has been monitored for several decades. The environmental monitoring has comprised analyses of different contaminants in sea water, mussel, fish, seaweed and sediments. Measurements of polychlorinated biphenyls (PCBs) in blue mussels (Mytilus edulis) some 17 years ago indicated a local source. In 2001 severe concentrations were measured in blue mussels and further investigations disclosed the primary source of PCBs in the Sørfjord. In 2002, extreme PCB-concentrations were found in cod (Gadus morhua) from the same area. However, no induction of EROD activity was detected, indicating the limitations of this assay as marker for PCB contamination. A future scientific challenge will be to understand the specific mechanisms and effects of such PCB accumulation in fish.     

地震学中的统计学原理（二）

3.4 模型检验模型检验即检查选用模型的特征与实际样本特征是否一致。选择模型与检验模型采用不相交的数据集较为理想。在做不到这一点的地方,检验需要考虑到模型已被调整到尽可能与数据密切拟合的事实,至少在某种意义上如此。     

国际矿物学协会新矿物及矿物命名委员会（CNMMN,IMA）1998年批准的新矿物

本文的资料是国际矿物学协会新矿物及矿物命名委员会提供的,以资矿物学家在新矿物研究工作中参考和对比。ＣＮＭＭＮ鼓励其成员将本文提交其所在国家的有关刊物发表。中译文由中国新矿物及矿物命名委员会供稿。文中所列的已经批准的新矿物的名称及其详细资料,将由每个新...     

泰国东北呵叻府苏拉娜里地区新生代硅化木及其古环境意义

摘要: 泰国东北部新生代硅化木十分丰富且保存完好。经对23 件木化石标本研究,已鉴定出真双子叶植物6 科7 属约13 种,包括Canarium sp． ( Burseraceae) ; Terminalia sp． vel Combretum sp． ,Terminalia sp． ( Combretaceae) ; cf． Irvingia sp． ( Irvingiaceae) ; Cynometroxylon holdeni,Cynometroxylon sp． ,cf． Cynometroxylon spp． ,cf． Millettia spp． ( Leguminosae) ; Careya spp. ( Lecythidaceae) ; Azadirachta sp． ( Meliaceae) ; 以及其他4 个分类群( 分类位置待定) 。这些高度分化的古植物群显示出与泰国东北部现存的混合落叶林、干旱阔叶林和干旱常绿林非常相似的特征,反映了该地区当时的古气候是近于湿润的热带疏林草原气候( 热带干湿气候) 。     

Distribution and controlling factors of phytoplankton assemblages in a semi-enclosed bay during spring and summer

The phytoplankton assemblages' patterns and their correlation to environmental factors were studied in Bohai Bay during spring and summer. Two zones, the northern (NWA) and southern (SWA) water area, were identified by cluster analysis based on their physical and chemical properties. Principal component analysis (PCA) showed that more phytoplankton species was found in the SWA with low nutrient concentration, while high phytoplankton abundance occurred in the NWA with high nutrient concentration. The seasonal variability in phytoplankton can be explained by water temperature, nutrient, and hydrodynamic conditions (includes mixing during spring and stratification during summer). Results of redundancy analysis (RDA) showed that silicate (SiO(4)) and soluble reactive phosphorus (SRP) were the most important environmental factors influencing the phytoplankton distribution during spring and summer, respectively. Hydrodynamics condition plays a key role in controlling variation of the environmental factors, which determined phytoplankton distribution in Bohai Bay.     

雅鲁藏布中新生代深水沉积盆地形成和演化(Ⅰ)——喜马拉雅造山带沉积特征及演化

通过对喜马拉雅三叠纪到第三纪区域沉积特征分析,阐明了雅鲁藏布喜马拉雅特提斯造山带从裂谷—被动大陆边缘—前陆盆地的沉积盆地演化史。随着以雅鲁藏布带为代表的喜马拉雅特提斯打开,三叠纪到早侏罗世为特提斯早期裂开的大陆边缘裂谷盆地。早期裂谷中心部位不是现在大陆缝合线的雅鲁藏布一带,而在低分水岭带。晚侏罗世到早白垩世,雅鲁藏布江南测为典型被动大陆边缘,其沉积盆地沉降、海平面变化与沉积作用相吻合。晚白垩世到第三纪为前陆盆地演化阶段,从沉积作用可以识别出晚白垩世晚期为造山第一暮,第三纪初为第二幕。     

Discovery of High Proper-Motion Ancient White Dwarfs: Nearby Massive Compact Halo Objects?

We present the discovery and spectroscopic identification of two very high proper-motion ancient white dwarf stars, found in a systematic proper-motion survey. Their kinematics and apparent magnitude clearly indicate that they are halo members, while their optical spectra are almost identical to the recently identified cool halo white dwarf WD 0346+246. Canonical stellar halo models predict a white dwarf volume density that is 2 orders of magnitude less than the rho approximately 7x10-4 M middle dot in circle pc-3 inferred from this survey. With the caveat that the sample size is very small, it appears that a significant fraction, approximately 10%, of the local dark matter halo is in the form of very old, cool, white dwarfs.