四角蛤蜊Mactra veneriformis对镉和汞污染胁迫的生理响应

本论文基于对我国沿海重金属污染加剧以及滩涂贝类资源衰退现象的关注，围绕典型滩涂贝类四角蛤蜊生物化学、细胞生物学和免疫学特征开展研究，调查了渤海湾天津近岸海域四角蛤蜊体内重金属含量和分布规律，以及四角蛤蜊对沉积物重金属的富集能力。室内模拟研究了四角蛤蜊对重金属镉和汞的富集能力及同化机制（assimilation mechanism）差异性，四角蛤蜊各组织对镉和汞的解毒机理和负载能力，以及重金属胁迫对四角蛤蜊血细胞结构和功能的损伤效应。研究结果可望为探讨四角蛤蜊受重金属胁迫细胞水平上的响应机制，揭示重金属污染和贝类资源衰退的关系，建立快速可靠的重金属污染生物标志物指标体系，开展生态健康评估和生境修复等提供科学依据。主要研究结果如下： 1．查明了渤海湾天津近岸四角蛤蜊体内和表层沉积物中Cd、Pb、Cu、Zn、Mn、Cr和Ni七种重金属的含量和周年时空分布特征；表层沉积物中Cd具有较强的污染程度和潜在生态风险，四角蛤蜊对重金属元素Cd和Pb具有较高的富集能力，对环境重金属污染具有很好的指示作用。 2．查明了Cd对四角蛤蜊在24h，48h和96h的半致死浓度（LC50）分别为15.96mg/L、5.15mg/L和2.38mg/L，汞的24h，48h和96h LC50分别为3.71mg/L，0.61mg/L和0.21mg/L。镉和汞对四角蛤蜊的安全质量浓度分别为0.0238mg/L和0.0021mg/L。 3．四角蛤蜊软体部对Cd和Hg的富集能力有显著差异。暴露过程中，四角蛤蜊软体部Cd和Hg的增加量分别为0.12-7.7µg/g和0.002-0.024µg/g，富集率分别为0.3-6.2%和0.11-0.68%，吸收率常数分别为0.07-1.10和0.001-0.005。 4．四角蛤蜊受Cd和Hg胁迫后，外套膜、鳃和肝胰腺的金属硫蛋白（MT）含量均在暴露浓度和胁迫时间上都有极显著变化。组织内MT含量的大小关系为：肝胰腺＞鳃＞外套膜。肝胰腺可以作为双壳贝类MT重金属污染指示研究的目标组织。四角蛤蜊对Cd和Hg不同的解毒机制，导致组织中MT的表达含量和Cd胁迫显著相关，而与Hg胁迫无显著相关性。 5．四角蛤蜊肝胰腺和鳃中抗氧化系统酶、脂质过氧化产物、酸性磷酸酶（ACP）和碱性磷酸酶（ALP）在不同Cd胁迫浓度和暴露时间下有显著差异。与对照组相比，超氧化物歧化酶（SOD）、过氧化氢酶（CAT）、谷胱甘肽过氧化物酶（GPx）的活力和丙二醛（MDA）含量均随着暴露时间的增加而增加，达到一个峰值，然后减低。而ACP和ALP活力则表现出先被抑制，然后升高的变化趋势。肝胰腺中CAT和GPx活力高于鳃，鳃中SOD和MDA含量高于肝胰腺，这种差异与两种组织不同的解毒机理有关。 6．重金属胁迫能够造成四角蛤蜊血细胞超微结构的损伤、溶酶体膜稳定性改变、微核和总畸形核生成，各种损伤均表现出明显的浓度依赖效应。2μg/L Hg暴露14天后，血细胞溶酶体膜中性红保持时间（NRR）、微核生成率（MN）和总畸形核生成率（TNA）与对照组相比没有显著差异。相同暴露时间下，25 μg/L Hg处理组血细胞NRR值低于25 μg/L Cd处理组，而MN和TNA值则相反，说明Hg胁迫对四角蛤蜊血细胞溶酶体膜具有较强的损伤作用。研究发现，NRR、MN和TNA三种指标对于衡量重金属污染对四角蛤蜊血细胞的毒性效应有很好的协同检测作用，可望作为有效的生物标志物在环境监测技术中得以应用。

最优变分伴随方法及在近岸水位资料同化中的应用

利用二维正压Princeton（POM）海洋模式模拟美国东海岸由表面风场产生的低频非潮汐水位变化特征。模式采用曲线正交网格，表面风场使用每3小时时间间隔、空间分辩率为48公里的EDAS（ETA Data Assimilation System）分析风场。沿岸潮汐观测资料（美国国家水位观测网）用来检验模式模拟结果以评估模拟结果的精度，这些观测资料也被用于动力同化模式中。在美国东海岸，表面风场是产生和引起低频水位及其变化的最重要的动力机制。观测资料的分析结果表明，非潮汐水位的最大振幅可达1以上，其对表面风场的响应大约滞后6～12小时左右。与观测资料相比，模式计算值的均方误差大约为8～12厘米，与观测资料之间的相关系统为0.54～0.91。为了获得更精确的模拟水位，提高实时水位预报系统的精度，本论文用伴随最优方法将尚岸水位观测资料同化到海洋动力模式中。建立一套实时水位预报同化系统。在该同化系统中，二维线性POM模式用作海洋基本模式（向前积分模式）。其伴随模式是通过拉格朗日（Lagrange）方法由离散的基本模式方程获得。观测水位与模拟水位之间的差被定义为价格函数。由于表面风场对美国东海岸低频水位的产生及其变化起着最重要的作用，表面风场的误差及风应力系统的误差都将引起模拟水位的误差。因此，在最优同化系统中，将表面风应力系统定义为控制变量。通过调整风应力系数改变风应力场，使模式计算的水位最好地接近观测值。有限记忆的准牛顿方法用于求解所形成的最优化问题。一致性“孪生”试验（假设的“观测数据”由模式本身产生，因此，控制变量的真实解是已知的）用来检验同化系统的正确性、有效性及收敛性。“孪生”试验结果表明该同化系统所求得的控制变量的解精确地收敛于真实解。在实测水位资料的同化试验中，设计了三种不同情况的试验，其对应的控制变量的个数分别为1，8，16。同化后模式结果表明，即使仅用一个控制变量，模式计算的水位比没有用同化技术的模式结果好，用16个控制变量的同化模式获得最好的结果，对这种情况，观测水位与同化模式的计算结果之间的相关系数在所有观测站均大于0.93，其计算结果的均方误差均小于5.3厘米。因此说同化模式的结果得到了很大的改进。实时水位预报结果表明，对于没有应用同化技术的预报系统，其预报水位均方误差在8.8～12厘米。同化技术对低频非潮汐水位预报结果的改进主要发生在前6小时。使预报的非潮汐水位的预报均方误差减少3厘米。

潮波模型的优化开边界方法研究

数值模式是潮波研究的一种有利手段，但在研究中会面临各种具体问题，包括开边界条件的确定、底摩擦系数和耗散系数的选取等。数据同化是解决这些问题的一种途径，即利用有限数量的潮汐观测资料对潮波进行最优估计，其根本目的是迫使模型预报值逼近观测值，使模式不要偏离实际情况太远。本文采用了一种优化开边界方法，沿着数值模型的开边界优化潮汐水位信息，目的是设法使数值解在动力约束的意义下接近观测值，获得研究区域的潮汐结果。边界值由指定优化问题的解来定，以提高模拟区域的潮汐精度，最优问题的解是基于通过开边界的能量通量的变化，处理开边界处的观测值与计算值之差的最小化。这里提供了辐射型边界条件，由Reid 和Bodine（本文简称为RB）推导，我们将采用的优化后的RB方法（称为ORB）是优化开边界的特殊情况。 本文对理想矩形海域（ E- E， N- N， 分辨率 ）进行了潮波模拟，有东部开边界，模式采用ECOM3D模式。对数据结果的误差分析采用，振幅平均偏差，平均绝对偏差，平均相对误差和均方根偏差四个值来衡量模拟结果的好坏程度。 需要优化入开边界的解析潮汐值本文采用的解析解由方国洪《海湾的潮汐与潮流》（1966年）方法提供，为验证本文所做的解析解和方文的一致，本文做了其第一个例子的关键值a,b,z,结果与其结果吻合的相当好。但略有差别，分析的可能原因是两法在具体迭代方案和计算机保留小数上有区别造成微小误差。另外，我们取m=20，得到更精确的数值，我们发现对前十项的各项参数值，取m=10,m=20各项参数略有改进。当然我们可以获得m更大的各项参数值。 同时为了检验解析解的正确性讨论m和l变化对边界值的影响，结果指出，增大m，m=20时，u的模最大在本身u1或u2的模的6%；m=100时，u的模最大在本身u1或u2的模的4%；m再增大，m=1000时，u的模最大在本身u1或u2的模的4%，改变不大。当l<1时， =0处u的模最大为2。当l=1时， =0处u的模最大为0.1，当l>1时，l越大，u的模越小，当l=10时，u的模最大为0.001，可以认为为0。 为检验该优化方法的应用情况，我们对理想矩形区域进行模拟，首先将本文所采用的优化开边界方法应用于30m的情况，在开边界优化入开边界得出模式解，所得模拟结果与解析解吻合得相当好，该模式解和解析解在整个区域上，振幅平均绝对偏差为9.9cm,相位平均绝对偏差只有4.0 ，均方根偏差只有13.3cm，说明该优化方法在潮波模型中有效。 为验证该优化方法在各种条件下的模拟结果情况，在下面我们做了三类敏感性试验： 第一类试验：为证明在开边界上使用优化方法相比于没有采用优化方法的模拟解更接近于解析解，我们来比较ORB条件与RB条件的优劣，我们模拟用了两个不同的摩擦系数，k分别为：0,0.00006。 结果显示，针对不同摩擦系数，显示在开边界上使用ORB条件的解比使用RB条件的解无论是振幅还是相位都有显著改善，两个试验均方根偏差优化程度分别为84.3%，83.7%。说明在开边界上使用优化方法相比于没有采用优化方法的模拟解更接近于解析解，大大提高了模拟水平。上述的两个试验得出， k=0.00006优化结果比k=0的好。 第二类试验，使用ORB条件确定优化开边界情况下，在东西边界加入出入流的情况，流考虑线性和非线性情况，结果显示，加入流的情况，潮汐模拟的效果降低不少，流为1Sv的情况要比5Sv的情况均方根偏差相差20cm,而不加流的情况只有0.2cm。线性流和非线性流情况两者模式解相差不大，振幅，相位各项指数都相近, 说明流的线性与否对结果影响不大。 第三类试验，不仅在开边界使用ORB条件，在模式内部也使用ORB条件，比较了内部优化和不优化情况与解析解的偏差。结果显示，选用不同的k,振幅都能得到很好的模拟，而相位相对较差。另外，在内部优化的情况下，考虑不同的k的模式解， 我们选用了与解析解相近的6个模式解的k,结果显示，不同的k,振幅都能得到很好的模拟，而相位较差。 总之，在开边界使用ORB条件比使用RB条件好，振幅相位都有大幅度改进，在加入出入流情况下，流的大小对模拟结果有影响，但线形流和非线性流差别不大。内部优化的结果显示，模式采用不同的k都能很好模拟解析解的振幅。

多源多时相SAR资料反演水下地形的同化模型

合成孔径雷达(SAR)是重要的微波传感器之一，在海洋遥感领域得到了广泛应用。浅海水下地形SAR探测是SAR海洋应用的重要部分之一，发展业务化水下地形SAR探测技术是水下地形SAR探测研究的最终目标。现有的水下地形SAR探测是基于单景SAR影像开展的，探测结果不能全面反映水下地形。因此，发展一种基于多源多时相SAR影像的水下地形反演方法是该研究方向的前沿问题。 本文基于水下地形SAR成像机制和袁业立（1997）导出的海波高频谱解析表达式，首次建立了基于多源多时相SAR影像的水下地形反演的同化模型与算法，并通过该模型在台湾浅滩水下地形SAR探测中的应用检验了该模型和算法的可行性。本文还开展了已有的浅海水下地形SAR探测技术（浅海水下地形单景SAR影像反演）在台湾浅滩水下地形探测中的应用研究，以及反演初始水深对水下地形SAR反演结果影响的研究。此外，本文还对中国近海水下地形SAR成像能力进行了分析。 在浅海水下地形SAR探测技术应用于台湾浅滩研究方面，基于7景SAR影像开展了台湾浅滩单景SAR影像反演计算，反演结果表明同一水下地形不同时相SAR影像反演结果不能全面反映真实地形特征。 在反演初始水深对水下地形SAR反演结果影响研究方面，通过不同初始水深条件下台湾浅滩水下地形SAR反演结果的比较分析，可以得出：初始水深影响水下地形反演结果的准确性，初始水深的选取需要较粗的实际水深的支持； 在多源多时相水下地形SAR反演同化模型研究方面， 建立了多源多时相水下地形SAR反演的同化模型与算法，通过基于多源多时相SAR影像的台湾浅滩五种不同情形水下地形反演计算，证明了多源多时相水下地形SAR反演同化模型和算法是可行的，并给出了基于多源多时相SAR影像的水下地形反演计算中SAR影像的选取原则。 在中国近海浅海水下地形SAR响应能力分析方面，基于对中国近海潮汐潮流状况、水下地形概况和已有中国近海SAR影像中水下地形特征等的分析，总结出中国近海适合开展浅海水下地形SAR探测的区域主要有：渤海海域、苏北近海海域、台湾海峡海域和南沙群岛海域。

The nitrogen isotopic composition of dissolved nitrate in the Yangtze River (Changjiang) estuary, China

The nitrogen isotopic composition of dissolved nitrate (delta N-15-NO3-) in surface water of the Yangtze River estuary was determined in four seasons of 2006. delta N-15-NO3- ranged from 0.4 parts per thousand to 6.5 parts per thousand and varied with seasons and geographic regions, reflecting the dynamics of nitrogen cycling in the estuarine ecosystem. delta N-15-NO3- was markedly lower in February than in other seasons and exhibited conservative mixing, which was probably attributed to the NO3- being sourced from the atmospheric deposition and agricultural fertilizer. In the upper estuary, the influence of riverine inputs was important during all surveys. in the turbidity maximum zone, nitrification was found with nitrate depleted in N-15 in May, whereas denitrification resulting in heavy delta N-15-NO3- played an important role in August. More enriched delta N-15-NO3- values coinciding with losses of nitrate concentrations based on the conservative mixing model were found in the adjacent marine area in May, and may reflect obvious phytoplankton assimilation of dissolved nitrate. In this manner, delta N-15-NO3- may be a sensitive indicator of nitrogen sources and biogeochemical processing existing in this estuary in conjunction with the variations of dissolved nitrate and other environmental factors. (C) 2009 Elsevier Ltd. All rights reserved.

Trace metal concentrations in suspended particles, sediments and clams (Ruditapes philippinarum) from Jiaozhou Bay of China

Suspended particulate matter (SPM), sediments and clams were collected at three sites in Jiaozhou Bay to assess the magnitude of trace metal pollution in the area. Metal concentrations in SPM (Cu: 40.11-203; Zn: 118-447; Pb: 50.1-132; Cd: 0.55-4.39; Cr: 147.6-288; Mn: 762-1670 mu g/g), sediments (Cu: 17.64-34.26; Zn: 80.79-110; Pb: 24.57-49.59; Cd: 0.099-0.324; Cr: 41.6-88.1; Mn: 343-520 mu g/g) and bivalves (Cu: 6.41-19.76; Zn: 35.5-85.5; Pb: 0.31-1.01; Cd: 0.51-0.67; Mn: 27.45-67.6 mu g/g) are comparable to those reported for other moderately polluted world environments. SPM showed a less clear pattern. Metal concentrations in sediments displayed a clear geographical trend with values increasing with proximity to major urban centers. The clams (on dry weight) showed a complex pattern due to the variability introduced by age-related factors. Cd showed an apparent reverse industrial trend with higher concentrations in clams collected at distant stations. Zn, Pb and Mn showed no clear geographical pattern, whereas Cu increased in the clams collected in the most industrialized area. In addition, the bioaccumulation factors (BAF) were calculated. The result indicated that the studied Ruditapes philippinarum in Jiaozhou Bay possessed different bioaccumulation capacities for Cd, Zn, Cu, Pb and Mn, and Cd, Zn had a relatively high assimilation of those metals from sediment particles. A significant relationship with clam age was observed for Zn (positive) and Cu (negative) suggesting different physiological requirements for both metals with age. Trace metal concentrations measured in the tissue of the investigated clam were in the range considered safe by the WHO for human use.

Nutrient structure of seawater and ecological responses in Jiaozhou Bay, China

Nutrient concentrations in seawater, and C, N, P, Si and chlorophyll a content in different-sized particulates were measured in Jiaozhou Bay, and C, N, P, Si composition in different-sized fractions of phytoplankton and their ecological responses to nutrient structure of the seawater were studied. Microphytoplankton and nanophytoplankton were dominant in Jiaozhou Bay. High C (16.50-20.97 unol L-1), N (2.46-2.99 mu mol L-1) and low P (0.06-0.12 mu mol L-1), Si (0.18-0.57 mu mol L-1) content, and high N/P (24.7-64.6) and low SUP (4.4-10.8), Si/N (0.06-0.20) ratios were found in all sized groups of particulates. These values reflected the elemental compositions of different-sized fractions of phytoplankton as being an ecological response to the nutrients in the seawater. The ratios deviated significantly from the Redfield values. The nutrient composition of seawater and particulates and their relationship to chlorophyll a showed that phytoplankton growth was possibly limited by Si. Si limitation appears favorable for controlling the ecological equilibrium of Jiaozhou Bay. Different-sized fractions of phytoplankton had different suitability to nutrient structures of the seawater. Among phytoplankton size groups, nanophytoplankton and microphytoplankton growths were more adaptable in eutrophic Jiaozhou Bay, and more competitive for assimilation of Si. This is consistent with their diatom-dominated composition, controlling the biomass and productivity of phytoplankton in Jiaozhou Bay. (c) 2006 Elsevier Ltd. All rights reserved.

The influence of diets containing dried bivalve feces and/or powdered algae on growth and energy distribution in sea cucumber Apostichopus japonicus (Selenka) (Echinodermata : Holothuroidea)

In recent years, bivalve feces and powdered algae have been used as the food sources of holothurians in China. In this study, growth and energy budget for sea cucumber Apostichopus japonicus (Selenka) with initial wet body,veights of 32.5 1.0 g (mean +/- SE, n=45) when fed with five different granule diets containing dried bivalve feces and/or powdered algae in water temperature 13.2-19.8 degrees C and salinity 30-32ppt were quantified in order to investigate how diets influence growth and energy distribution and to find out the proper diet for land-based intensive culture of this species. Results showed that diets affected the food ingestion, feces production, food conversion efficiency and apparent digestive ratios, hence the growth and energy budget. Sea cucumbers fed with dried feces of bivalve showed poorer energy absorption, assimilation and growth than individuals fed with other four diets; this could be because feces-drying process removed much of the benefits. Dried bivalve feces alone, therefore, were not a suitable diet for sea cucumbers in intensive cultivation. The mixed diets of feces and powered algae showed promising results for cultivation of sub-adult Apostichopus japonicus, while animals fed with powdered algae alone, could not obtain the best growth. According to SGR of tested animals, a formula of 75% feces and 25% powdered algae is the best diet for culture of this species. Extruded diets were used in the present experiment to overcome shortcomings of the traditional powdered feeds, however, it seems a conflict exists between drying bivalve feces to form extruded diets and feeding sea cucumbers with fresh feces which contain beneficial bacteria. Compared with other echinoderms, in holothurians the energy deposited in growth is lower and the energy loss in feces accounts for the majority of the ingested energy. Such detailed information could be helpful in further development of more appropriate diets for culture of holothurians. (c) 2006 Elsevier B.V. All rights reserved.

A Simulative Study on Effects of Climate Warming on Nutrient Contents and In Vitro Digestibility of Herbage Grown in Qinghai-Xizang Plateau

The increasing trend of air temperature along with the climate warming has been accepted gradual-ly by scientists and by the general public. Qinghai-Xizang Plateau, a unique geographic unit due to high-altitude climate, is one of the most susceptible regions to climate warming. Its ecosystem is very fragile and sensi-tive to climate change. In order to get a better understanding of the impacts of climate warming on the nutrient contents of herbage grown in Qinghai-Xizang Plateau, a simulative study was implemented at Daban Moutain by using temperature differences resulted from sites selected at different altitudes and nutrient contents and in vitro digestibility were determined for assessing the quality of the grown herbage. There were significant downtrends in crude protein (CP), ether extract (EE) and nitrogen free extract (NFE) contents of herbage along with the increase of temperature. It had a positive correlation between temperature and content of acid detergent fibre (ADF), acid detergent lignin (ADL) in herbage. In vitro digestibility of herbage decreased along with the in-crease of temperature. The results of this study indicated that climate warming significantly influence nutrient contents and in vitro digestibility of herbage grown in Qinghai-Xizang Plateau. It is suggested that the future climate warming especially the gradual rise of the night temperature could cause negative effect on herbage quality grown in Qinghai-Xizang Plateau by decreasing CP, EE, and NFE contents and increasing some indi-gestible ingredients such as crude fibre (CF), neutral detergent fibre (NDF), ADF, and ADL. This, conse-quently, decreases the ruminant assimilation ability.

Effects of vegetation control on ecosystem water use efficiency within and among four grassland ecosystems in China

Through 2-3-year (2003-2005) continuous eddy covariance measurements of carbon dioxide and water vapor fluxes, we examined the seasonal, inter-annual, and inter-ecosystem variations in the ecosystem-level water use efficiency (WUE, defined as the ratio of gross primary production, GPP, to evapotranspiration, ET) at four Chinese grassland ecosystems in the Qinghai-Tibet Plateau and North China. Representing the most prevalent grassland types in China, the four ecosystems are an alpine swamp meadow ecosystem, an alpine shrub-meadow ecosystem, an alpine meadow-steppe ecosystem, and a temperate steppe ecosystem, which illustrate a water availability gradient and thus provide us an opportunity to quantify environmental and biological controls on ecosystem WUE at different spatiotemporal scales. Seasonally, WUE tracked closely with GPP at the four ecosystems, being low at the beginning and the end of the growing seasons and high during the active periods of plant growth. Such consistent correspondence between WUE and GPP suggested that photosynthetic processes were the dominant regulator of the seasonal variations in WUE. Further investigation indicated that the regulations were mainly due to the effect of leaf area index (LAI) on carbon assimilation and on the ratio of transpiration to ET (T/ET). Besides, except for the swamp meadow, LAI also controlled the year-to-year and site-to-site variations in WUE in the same way, resulting in the years or sites with high productivity being accompanied by high WUE. The general good correlation between LAI and ecosystem WUE indicates that it may be possible to predict grassland ecosystem WUE simply with LAI. Our results also imply that climate change-induced shifts in vegetation structure, and consequently LAI may have a significant impact on the relationship between ecosystem carbon and water cycles in grasslands.

Independence of alpine meadow plants from soil organic matter for nitrogen supply: evidence from stable nitrogen isotopes

Stable nitrogen isotope signatures of major sources of mineral nitrogen ( mineralization of soil organic nitrogen, biological N-2 fixation by legumes, annual precipitation and plant litter decomposition) were measured to relatively define their individual contribution to grass assimilation at the Haibei Alpine Meadow Ecosystem, Qinghai, China. The results indicated that delta N-15 values (- 2.40 parts per thousand to 0.97 parts per thousand) of all grasses were much lower than those of soil organic matter (3.4 +/- 0.18 parts per thousand) and mineral nitrogen ( ammonium and nitrate together,7.8 +/- 0.57 parts per thousand). Based on the patterns of stable nitrogen isotopes, soil organic matter (3.4 +/- 0.18 parts per thousand), biological N-2 fixation (0 parts per thousand), and precipitation (- 6.34 +/- 0.24 parts per thousand) only contributed to a small fraction of nitrogen requirements of grasses, but plant litter decomposition (- 1.31 +/- 1.01 parts per thousand) accounted for 67%.

藏北可可西里碰撞后钾质火山作用和岩石成因

Post-collisional, potassic igneous rocks are widely distributed in the Hoh Xil area of the northern Tibetan Plateau. Based on the field work, petrography, mineral chemistry, K-Ar geochronology, element and Sr-Nd-Pb isotope geochemistry, this thesis systematically studied the spatial and temporal distribution of the volcanic rocks, chemical characteristics, formation mechanism and partial melting mechanism of the magma source region, geodynamic setting of magmatism, as well as crustal assimilation and fractional crystallization (AFC). The results show that: 1. The Miocene (7.77-17.82 Ma) volcanic products dominantly are trachandesite and trachy, and subordinate rhyolites, associated with stike-slip faults and thrust faults, formed morphology of small lava platforms and cinder cones. 2. Phenocrysts in the lavas are augite, andesine, sanidine, calcic amphibole and subordinate orthopyroxene, biotite and Ti-Fe oxides, displaying typical quench texture. Equilibrium temperatures and pressures of clinopyroxene phenocrysts indicate the magma chamber is located in upper-middle crust. 3. Rhyolites are the products of crustal melting and fractionation of shoshonitic magmas. The source region of intermediate magmas is enriched continental lithospheric mantle, which contains residual minerals such as phlogopite, rutile and spinel, and enriched by subducted sediments during earlier multi-episodes of subduction. 4. Upwelling of asthenosphere provides heat for source region melting, and faults provide channels for magma eruption. 5. Northward underthrusting of Indian continental lithosphere and southward of backstop of Asian continental lithosphere resulted in upwelling of hot asthenosphere. Geochemical characteristics of the potassic magmatism in North Tibet are dominantly controlled by source region composition, partial melting, and crustal assimilation and fractional crystallization (AFC).

北祁连与块状硫化物矿床有关的早古生代火山岩的地球化学研究

Different conclusions from previous work are made from the geochemical study for the early Paleozoic volcanic rocks hosting massive sulfide deposits in the north Qilian Orogen. The main points are: (1)The geochemical characteristics of the basalts and rhyolites from the Baiyin deposit are not consistent with that of the volcanic rocks in the continental rift setting, but show the relationship with subduction. The basalts and rhyolites from the Baiyin deposit are probably individual tectonic slice piled by subduction, and there is no bimodal volcanic rock suite occurred in the Baiyin deposit. Zircon U-Pb dating constrains the magmatic emplacement of basalts and rhyolites at 475±10Ma and 453±12Ma, respectively. The basalts are characterized by enriched Th and Sr, and depleted Nb, Ta and Ti. They have relatively high Th/Nb ratios between 0.9 and 1.3. Their εNd(T) values vary from -1.2 to +3.4. The chemical and isotopic compositions display a typical subduction-related signature, and they suggest that an enriched component with the isotopic composition of EMII might have contributed to the generation of the Baiyin basalts. The basalts were likely formed in a mature island-arc or a volcanic arc built on comparatively young or thin continental crust in an active continental margin. The rhyoIites have low concentrations of LILE compared to the basalts. They do not seen to have a relationship with the basalts, because of their significantly higher εNd(T) values (+4.3～+7.7). The high and positive εNd(T) values also rule out their derivation from anatexis of the continental crust. A modeling study suggests that the source.of the Zhe-Huo and Xiaotieshan rhyolites is similar to boninite and IAT (island-arc tholeiite), and hence indicating an intra-oceanic arc environment. (2) The formation of the Shangliugou volcanic rocks from .Qilian area is also related to subduction. The basaltic andesite have low TiO_2(0.45～0.63%) and P_2O_5(0.04～0.09) content, and high Th/Nb ratios (0.3～0.6). They show flat REE patterns. Their εNd(T) values vary in a narrow range from +4.8 to +6.4. The chemical and isotopic compositions indicate that they are derived from a slightly depleted mantle source and are fromed in intra-island arc setting. The rhyolites show calc-alkaline trend. They show enriched LREE and fiat HREE patterns with obvious negative Eu anomaly. They have high Th/Ta ratios (5.0 ～ 11.7) and large negative εNd(T) values (-2.6 ～ -8.4). The rhyolites are formed in active continental margin and result from a mixed process of two endmembers, or crust assimilation. (3) The metal elements of the volcanic-hosted massive sulfide deposit have two sources, the copper and zinc are derived from rhyolitic magmas whereas the lead are probably related to old sediments overlying the rhyolites. (4) It is suggested here that the volcanic rocks hosting massive sulfide deposit in the north Qilian orogen, which are previously considered as a bimodal suite of Neo-proterozoic to middle Cambrian age in a continental rift, are virtually related to subduction magmatism in Ordovician age, and there might have no continental rift magmatism of Neo-proterozoic to middle Cambrian in the north Qilian.

印象形成中同化和对比效应研究

Impression formation is an important aspect of person perception and has important interpersonal consequences. There are assimilation and contrast effects in impression formation and is still considerable debate regarding the best way to account for them. This present research used trait-implying sentences as priming materials, trait inferences sever as self-generated primes, examined the effect of different trait knowledge in assimilation and contrast effects. Experiment 1 determined the priming and target stimuli of this research by pretest. In experiment 2, participants read trait-implying sentences and resulted in trait inference as self-generated primes, examined the influence of trait activation on impression formation. The results indicated that participants instructed to memorize trait-implying sentences showed assimilation effect, whereas participants instructed to form impression from trait-implying sentences showed contrast effect. Difference to previous studies that emphasized the impact of awareness of the prime in impression formation, this research paid attention to the impact of different trait knowledge that resulted from trait inference. Experiment 3 studied the influence of actor salience on impression formation. The results indicated that when trait-implying sentences that described actors with names and were accompanied with photos of the actors, participants showed contrast under both memorization and impression instructions. Experiment 4 studied the influence of attribution context on assimilation and contrasts. The results showed that contrast ensued when trait-implying sentences were accompanied with the information that suggested a person attribution, whereas assimilation ensued when that information suggested a situation attribution, independent of processing goals. Experiment 5 made a direct test of the effect of different trait knowledge in impression formation. The results discovered that when abstract trait concepts were activated they act as a general interpretation frame in encoding stage, whereas when specific actor-trait links were activated, the activated information is likely to be used as a comparative standard in judgment stage. All studied indicated that there are two types of activated trait knowledge in trait inference: abstract trait concepts versus specific actor-trait links. When trait inference activated abstract trait concepts, the activated information serves as interpretation frame and lead to assimilation effect during impression formation, when trait inference activated specific actor-trait links, the activated information is more likely to be used as a comparative standards and resulted in contrast effects. These findings have important implications for understanding the mechanism of impression formation and practical values for interpersonal communication.