90年代世界贸易发展及空间格局变化的新特点

在世界贸易组织、日趋强烈的开放的区域主义倾向、跨国公司强劲的直接投资影响下，世界贸易正在经历着巨大变化，处在一个新的转换时期。本文从影响当今世界贸易发展的多重因素分析，揭示90年代世界贸易增长、内容结构以及空间格局发展变化的新特征，并展望世界贸易的未来发展。     

中低温对流型地热系统

中低温对流型地热系统在自然界和我国有着广泛的分布。这类地热系统在阐明地区构造活动性、地热资源形成、分布以及水－岩相互作用和有用元素富集成矿等方面均有着十分重要的意义。文章重点介绍中低温对流型地热系统的特点及其形成模式、在我国的分布，并以漳州地区为例作出实例剖析。     

Modelling of soil temperature profiles using data from the pilot experiment at Anand

We present some preliminary results from a multi-layer soil temperature finite-difference model using the data set obtained during the pilot experiment on land surface processes at Anand. We hope that the present results will prove useful during the final field experiments scheduled for the coming monsoon season.     

低温条件下有机酸对铁、铜的淋滤实验研究

水／岩作用实验研究表明，在低温条件下柠檬酸、草酸和酒石酸对岩石中的铁、铜都有很高的淋滤率。这表明，在表生地质作用过程中有机酸对成矿元素有很强的活化能力。实验研究同时发现，有机酸对成矿元素的活化能力受其分解温度的限制，由于大部分有机酸的分解温度都在２５０℃以下，因而有机酸对成矿元素的活化仅限于低温条件。本次研究还显示，判断一种岩石能否成为矿源层，不能简单的以其中成矿元素的含量高低作为标准，其中更关键的因素是元素在岩石中的存在形式，如果成矿元素在岩石中难以活化的形式存在，那么含量再高也无法提供成矿物质     

鄂北—豫南地区榴辉岩相岩石变质作用演化特征

鄂北－豫南地区榴辉岩相变质岩石类型多样，其野外产状和岩石化学特征反映了原地变质成因。根据区域地质及榴辉岩相变质岩石的野外产状，结合榴辉岩中石榴石绿辉石的Ｆｅ２＋－Ｍｇ互换温度计所计算出的峰期变质温度，将本区榴辉岩分为两类，一类为中温榴辉岩，产于晚太古界—早元古界大别群，为Ｂ类榴辉岩，由绿帘角闪岩相岩石进变质形成。榴辉岩相变质作用分为两阶段，首先为柯石英榴辉岩相阶段，其峰期变质条件为Ｔ＝６００℃～７００℃，Ｐ＝２．７～３．０ＧＰａ，然后近等温降压，出现蓝闪石等含水矿物，为蓝闪石榴辉岩相阶段，此时水活度在榴辉岩相变质过程中起着重要作用；另一类为低温榴辉岩，产于中元古界七角山组，为Ｃ类榴辉岩，由蓝片岩相岩石进变质形成，其峰期变质条件为Ｔ＝４９０℃～５６０℃，Ｐ＜１．５ＧＰａ。中温榴辉岩与低温榴辉岩具有不同的变质作用特征。最后讨论了本区高压变质带的成因演化。     

0.25—3.75GPa和20—370℃条件下0.025molNaCl溶液电导率研究

在０．２５－３．７５ＧＰａ和２０－３７０℃条件下测量了ＮａＣｌ溶液的电导率。结果表明（１）电导率随温度增高而增大，且电导率的对数与温度的倒数为线性关系，但不同压力不其斜率不同。（２）电导率与压力的 关系较为复杂，存在着不连续性。即在２．２５－３．３７ＧＰａ压力范围，电导率随压力增大而增大；在１．２５－２．００ＧＰａ压力范围，电导率与压力几乎无关；０．７５ＧＰａ压力的电导率高于相邻力的电导率。上述。     

A bivariate meta-Gaussian density for use in hydrology

Convenient bivariate densities found in the literature are often unsuitable for modeling hydrologic variates. They either constrain the range of association between variates, or fix the form of the marginal distributions. The bivariate meta-Gaussian density is constructed by embedding the normal quantile transform of each variate into the Gaussian law. The density can represent a full range of association between variates and admits arbitrarily specified marginal distributions. Modeling and estimation can be decomposed into i) independent analyses of the marginal distributions, and ii) investigation of the dependence structure. Both statistical and judgmental estimation procedures are possible. Some comparisons to recent applications of bivariate densities in the hydrologic literature motivate and illustrate the model.     

Conductivity of NaCl solution at 0.4–5.0 GPa and 25–500 °C

NaCI-H₂O is the most fundamental ternary system in geology. Until now, the measurements of electrical conductivity of NaCl solutions are still little at high pressures (> O.5 GPa) We measured the conductivity of 0.01 m NaCl solution at 0.4–5.0 GPa and 25-500°C. The results are consistent with that of Quist and Marshall (1968) at 0.4 GPa. The conductivity of NaCl solution increases with increasing temperature. The results also show that the conductivity of NaCl solution changes little with increasing pressure below 1.5 GPa and changes rapidly with increasing pressure above 1.5 GPa. The rapid increase of the conductivity of NaCl solution may play an important role in many geological processes (such as the genesis of ore deposits under hydrothermal condition) and other fields. Project supported by the National Natural Science Foundation of China.     

The temporal and spatial characteristics of the surface air temperature variations over the Antarctic and its surrounding area

The characteristics of the spatial distribution, temporal variations trend and oscillation for the surface air temperature variations during 1957—1993 in the Antarctic and its surrounding area were analyzed. The results show that the short-time climate change in the Antarctic is complex both temporally and spatially. The Antarctic is by no means the strongest responding region to the global greenhouse effect. There is a distinguished difference in the trends of the temperature changes for the Antarctic and global mean, which could not be explained simply by the global greenhouse effect. Project supported by the National Antarctic Key Project of China (85-905).     

40Ar/39Ar geochronology and exhumation of mylonitized metamorphic complex in Changle-Nanao ductile shear zone

New⁴⁰Ar/³⁹Ar plateau ages from rocks of Changle-Nanao ductile shear zone are 107.9 Ma(Mus), 108.2 Ma(Bi), 107.1 Ma(Bi), 109.2 Ma(Hb) and 117.9 Ma(Bi) respectively, which are concordant with their isochron ages and record the formation age of the ductile shear zone. The similarity and apparent overlap of the cooling ages with respective closure temperatures of 5 minerals document initial rapid uplift during 107–118 Ma following the collision between the Min-Tai microcontinent and the Min-Zhe Mesozoic volcanic arc. The⁴⁰Ar/³⁹ Ar plateau ages, K-Ar date of K-feldspar and other geochronologic information suggest that the exhumation rate of the ductile shear zone is about 0.18–1.12 mm/a in the range of 107–70 Ma, which is mainly influenced by tectonic extension.