Diurnal variation of phytoplankton community in a high frequency area of HABs: Daya Bay, China

Phytoplankton community was investigated in the cage culture area of Daya Bay during a diurnal cycle. Two rainfalls occurred during the course of the experiment and decreased the surface seawater salinity in the aquaculture area. A total of 38 species were identified, of which the dominant species included Pseudo-nitzschia spp. and Skeletonema costatum. Water stratification obstructed the vertical migration of dinoflagellates. Statistical analysis indicated that Synechococcus showed negative relationship with silicate and ammonia, which indicated that Synechococcus adapted to grow at oligotrophic environment. Phytoplankton community structure implied the risk of Pseudo-nitzschia spp. blooms in the aquaculture area of Daya Bay.     

内蒙古苏尼特左旗第三纪地层研究新进展

本文探讨了内蒙古苏尼特左旗地区第三纪地层划分问题，阐明了区调工作中所取得的新进展。利用新发现的哺乳动物化石证明了始新统伊尔丁曼哈组的存在，并将中新统通古尔组细分为三段。运用不整合面、古地磁、孢粉和化学分析资料对必鲁图东南的新第三系进行了分解，从原定的通古尔组中划分出了宝格达乌拉组。对原定的宝格达乌拉组进行了重新认识，将其更名为塔木钦塔拉组，其时代为中更新世晚期。     

运用信息技术 提高管理水平

本文针对目前我国勘察设计企业管理现状，指出信息技术的应用在勘察设计企业管理中的促进作用；它可使管理者树立规范化、制度化的工作方法，并在许多方面为勘察设计企业创造价值和效益。     

Thermal and petrological structure of the lithosphere beneath Hannuoba, Sino-Korean Craton, China: evidence from xenoliths

Deep-seated xenoliths entrained in the Hannuoba basalts of the northern Sino-Korean Craton include mafic and felsic granulites, mantle wall-rock from spinel– and garnet–spinel peridotite facies, and basaltic crystallisation products from the spinel-pyroxenite and garnet-pyroxenite stability fields. The mineral compositions of the xenoliths have been used to estimate temperatures and, where possible, pressures of equilibration, and to construct a geothermal framework to interpret the upper mantle and lower crustal rock-type sequences for the region. The xenolith-derived paleogeotherm is constrained in the depth interval of 45–65 km and like others from areas of young basalt magmatism, is elevated and strongly convex toward the temperature axis. Two-pyroxene granulites give the lowest temperatures and garnet pyroxenites the highest, while the spinel lherzolites fall between these two groups. The present-day Moho beneath the Hannuoba area is defined at 42 km by seismic data, and coincides with the deepest occurrence of granulite. Above this boundary, there is a lower crust–upper mantle transition zone about 10-km thick, in which spinel lherzolites and mafic granulites (with variable plagioclase contents) are intermixed. It is inferred that this underplating has resulted in a lowering of the original pre-Cenozoic Moho (then coinciding with the crust–mantle boundary, CMB) from about 30 km to its present-day position and was due to intrusions of basaltic magmas that displaced peridotite mantle wall-rock and equilibrated to mafic granulites. Trace element patterns of the diopsides (analysed by laser ablation-ICPMS) from the Cr-diopside series spinel lherzolites and associated layered xenoliths (spinel lherzolites and pyroxenites) indicate a fertile uppermost mantle with moderate depletion by low degrees of partial melting and little evidence of metasomatic activity. The similarity in major and trace element compositions of the minerals in both rock types suggests that the layered ultramafic xenoliths formed by mantle deformation processes (metamorphic segregation), rather than by melt veining or metasomatism.     

日、月对孕震区的水平引潮力与震源机制的关系

根据计算日、月对孕震区水平引潮力方位角的表达式及美国哈佛大学提供的全球 Mw≥7.0的矩张量地震目录 ,选取了 1 980年 1月至 1 999年 1 2月全球发生的 (Mw≥ 7.0 ) 2 4 2次地震。利用地震目录中提供的地震矩张量参数 ,计算了每次地震发震应力场 P轴、T轴的方位角。同时计算了每次地震时日、月对震中区水平引潮力的方位角。将此方位角与 P轴、T轴以及二组断层面的走向进行对比分析。结果表明 ,日、月对震中区的水平引潮力方向与 P轴、T轴的方位角及二组断层面的走向互相平行或互相垂直 ,其平行或垂直的一致性非常好。平行或垂直相差在1 0°、2 0°、30°之内的发震概率分别达到了 0 .41 4、0 .736、0 .945。这个结果表明 ,日、月对孕震区的水平引潮力与大地震的发生密切相关。并进一步讨论了日、月对孕震区的水平引潮力对大地震发生的调制作用     

西安地裂成因力学问题初探

给出了西安地裂的构造模型,并用断裂力学原理分析了地裂的形成与扩展过程,准定量地比较了抽取地下水所引起的地面不均匀沉降以及构造运动所产生的地裂位移在地裂总位移中所占的比例。提出了构造对地裂发育不但有静态控制作用而且有动态控制作用。认为西安地裂是构造地裂,而西安地裂的致灾作用主要是由过量抽取地下承压水所引起的。     

两种Hannig加权的复量Burg算法及其在声达中的应用

本文提出两种自回归(AR)谱估计方法,它们是Hanning数据自适应加权和Hanning加权的复Burg方法(CHDAB和CHB)。它们的特性与当今最好的一类AR谱估计方法,即数据自适应加权的Burg方法(DAB)一样好,而且算法简单,易于选择初始的两个反射系数。本文把CHDAB和CHB两种方法应用于声达信号的谱估计,在单谱峰的情形下,获得的结果明显优于FFT。     

PROGRESS OF STUDIES ON THE INTERNAL TIDE GENERATED BY THE PASSAGE OF BAROTROPIC TIDE OVER CONTINENTAL SHELF/SLOPE

Various aspects of studies on internal tides are reviewed .Both beam-like structure and modal structure of internal tides may exist in the ocean . Bottom intensifications are caused by many factors .e.g. upstream blocking , which is the result of nonlinear interaction among waves . The energy may decay very fast so that internal tides are mostly locally generated .Internal tides may have considerable residual currents.In a 3-D frame, numerical study revealed that internal waves may interfere with each other to cause strong motions fer from the generation sources.The mechanism that determines how the lee waves break to form various nonlinear waves such as solitary waves, hydraulic jumps and internal surges or bores remains unclear. Analytic study is difficult , so numerical method may be effective . A radiation condition on the open boundary must be employed. A complete 3-D model may gain interesting result.Study on internal tides in China is limited to field observations and data analysis .     

计算井水位对固体潮和气压滞后响应的新方法

提出了一种计算井水位对固体潮和气压滞后响应的新方法.利用杜得森潮汐展开和泰勒级数展开,导出了计算井水位固体潮系数和气压系数以及滞后时间公式,并给出了考虑滞后影响的井水位固体潮和气压改正公式.利用该法处理了鲁03井水位和气压观测资料,求出该井水位固体潮系数为1.8mm/10~_(-3),水位对固体潮响应的滞后时间为1.53小时,气压系数为6.4mm/hPa,滞后时间为1.5小时。与以前的一般回归分析方法相比,改正后的水位中误差明显减小,改正效果较好。     

Quantitative correction of influence of rain on well water level

In this paper a new method of the quantitative correction of influence of the rain on the water level in a well is given. Using the faltung filtering and polynary regression, considering the effect of the rain on the well water level with the lag “memory”, the correction of the influence of the rain on the well water level is made. The result of correction of the water level in the well Lu-08 by the rain shows that the correction result of this method is better. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 202–207, 1993. This study was supported by the Chinese Joint Seismological Science Foundation. Thank The Seismic Office of Victory Oil Field for their help in gathering data of the well Lu-08.