澳大利亚阿得雷德地槽晚前寒武系的古地磁

本文叙述了阿得雷德地槽北部时限为 850～570百万年沉税岩和火山岩的古地磁研究成果。这些资料取自连续的地层剖面,但缺乏绝对年龄控制。褶皱检验和野外关系使笔者能够勾划出该时期相对简单和连续的视极移轨迹。原生磁化作用按年代可分为四个部分。自老到新:乌尔坦纳火山岩(λ=62S,φ=344 E;dp=16°,dm=18°);麦岭济纳冰碛岩(λ=45S,φ=346E,dp=06°,dm=11°),安捷派纳组(λ=33S,φ=344 E,dp=09°,dm=16°);布拉钦纳组(λ=33S,φ328E,dp=12°,dm=20°),业已鉴别出可能为早寒武世—奥陶纪的次生磁化作用有:乌尔坦纳火山岩(λ=36N,φ=087E,dp=13°,dm=26°),科普莱石英岩(λ=36S,φ=010E,dp=07°,dm=15°),麦岭济纳冰债岩(λ=01S,φ=065E,dp=08°,dm=14°),塔普莱山组(λ=33S,φ=344E,dp=08°,dm=15°),布耶劳组(λ=07S,φ=017E,dp=09°,dm=14°)。所研究的许多地层单元还可能存在第三纪或中生代的次生磁化作用。结合阿得雷德地槽南部古地磁研究成果,新资料证明,自中元古代以来,阿得雷德地槽没有发生明显的隆曲,地槽内的特殊S形构造是原生构造特征。新资料除能够阐述和澄清东南构造岩块的晚前寒武纪视极移轨迹史之外,还证实阿得雷德地槽的沉积作用在阿得雷德时期是发生于中至低纬度,因此证实该区晚前寒武纪冰川(或冰川海洋)沉积作用处于低纬度。     

Puziwan Gold Deposit in Shanxi, China: A Special Linear Cryptoexplosive Breccia Type Gold Deposit

The Puziwan gold deposit is a special linear cryptoexplosive breccia type deposit found in northeastern Shanxi, China, in recent years. The deposit is located in a secondary metallogenic. belt of the most famous Au-Ag polymetallic metallogenic belt along the north margin of the North China platform. The secondary metallogenic belt is a synmagmatic tension-shear fault-fracture belt of ENE linear trend. The Indosinian cryptoexplosive breccia body, quartz monzonitic porphyry (beschtauite breccia), quartz monzonite (243.7 Ma, K-Ar), Yanshanian granite-porphyry (105±6 Ma, Rb-Sr) and orebodies mostly occur as dykes or veins and short lenses along the structural fracture belt. The orebodies are emplaced in the fractured cryptoexplosive breccia body in the tectonomagmatic belt and their attitude is consistent with that of the breccia body. The orebodies have two types: one is shallow-seated thick and big ones, which are short-lenticular in plan and wedge-shaped in cross section, shallow buried, large in size a     

Sedimentary Features and Sea-Level Changes Reflected in Drill Holes in the Zhuhai Area

Experimental examinations and analyses have been made of the sediments from drill holes in the Zhuhai area, Guangdong Province. The studies show that there occurred four transgressions in this area over the historical times. The first transgression occurred at 7500 a B.P., with the maxium sea level up to about 1 m above the present level. The second transgression occurred at 5750 a B.P., with the sea level possibly 4 m higher than the present. The third and fourth transgressions took place at 4650 a B.P. and 2600 a B.P. respectively, which lasted for a long time with multiple fluctuations. The fifth transgression is in process. It could be predicted that the sea level at Zhuhai would rise by 15-20 cm in the coming 50 years.     

APPLICATION OF THE TRRL FLOOD ESTIMATION MODEL IN HYDROLOGICAL FORECASTING FOR CATCHMENTS WITH LIMITED DATA A CASE STUDY

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Urban growth in South Asia

The author discusses urbanization in Southern Asia during the period 1950-1980 using U.N. estimates. Urbanization in the region as a whole is compared with trends in other developing regions, and differences among the experiences of seven countries of Southern Asia are examined. Tabular information is provided on urbanization levels and urban population growth rates for Bangladesh, Bhutan, India, Maldives, Nepal, Pakistan, and Sri Lanka.     

Numerical simulation of organic chemicals in a marine environment using a coupled 3D hydrodynamic and ecotoxicological model

For ecotoxicological risk assessment in a marine ecosystem, we constructed a coupled three-dimensional hydrodynamic and ecotoxicological model (EMT-3D), and applied it to Tokyo Bay. The model was calibrated with field data obtained in 2002. The results of sensitivity analysis for dissolved Bisphenol A showed that biodegradation rate was the most important factor for concentration change. Bioconcentration coefficient was the most important factor for Bisphenol A in phytoplankton. Therefore, the parameters must be carefully considered in the modeling. The mass balance results showed that standing stocks of Bisphenol A in water, in particulate organic carbon and in phytoplankton are 7.85 x 10(4), 1.78 x 10(2) and 3.44 x 10(-1) g, respectively. With respect to flux, biodegradation in the water column had the highest value of 1.06 x 10(3) g/day, and next were effluent to the open sea, partition to particulate organic carbon, and bioconcentration in phytoplankton.     

太平洋西部中国沿岸海平面的变化

在有关世界大陆架地形和沉积的许多著作中,已对更新世冰期的低海平面作过研究。目前的残留海岸沉积和化石深度表明,冰川消溶前的海平面可能比现代低150米。海平面上升的大约深度和年代,是根据对残留的或准化石的海岸贝壳,和对从大陆架挖取或钻     

O,p'-DDT induction of vitellogenesis and its inhibition by tamoxifen in Nile tilapia (Oreochromis niloticus)

In order to investigate the mechanism by which o,p'-DDT disrupts endocrine functioning of Nile tilapia in vivo, the estrogenicity of o,p'-DDT was investigated in conjunction with 17beta-estradiol (E2) and tamoxifen. Mature, male tilapia were treated intraperitoneally with o,p'-DDT (60 mg/kg, one dose) or E2 (5 mg/kg, four doses) in the presence or absence of tamoxifen (5 mg/kg, six doses) for 12 days and then plasma vitellogenin (Vtg) (measured as alkaline-labile phosphorous), E2, and testosterone (T) were measured. Vtg levels were increased dramatically by E2 (1,744 +/- 171 microg/ml) and moderately by o,p'-DDT (82 +/- 15 microg/ml) compared with controls (23 +/- 3.5 microg/ml). Tamoxifen alone had no effect on Vtg production, but inhibited both E2 and o,p'-DDT stimulated vitellogenesis. T levels were reduced with E2 administration (1,688 +/- 383 pg/ml) and declined further with the combined treatment of E2 and tamoxifen (281 +/- 70 pg/ml), compared with controls (6,558 +/- 1,438 pg/ml). Tamoxifen or o,p'-DDT alone did not affect T levels, but their combined treatment did (2,069 +/- 647 pg/ml). The results of this study suggest that o,p'-DDT is weakly estrogenic in male tilapia, and that this activity may be mediated through the estrogen receptor.     

中印度洋强变形带内的洋底构造

由地震活动性、地球形状、重力异常和异常的热流反映出在赤道附近的中印度洋盆地内，沉积物和基底的强烈变形，显示出在长波长和短波长两方面的板内挤压岸石圈变形的明显证据．地震反射剖面显示，基底东西向线型波状起伏以及与地球形状不规则有关的基底高和低，