北极巴罗Elson湖过去450年气候与环境变化记录

北极阿拉斯加巴罗地区Ｅｌｓｏｎ湖长６０ｃｍＡＢ—６７钻孔岩芯提供了过去４５０年连续的高分辨环境变化记录。综合分析２１０Ｐｂ测年、沉积物粒度、有机质、化学元素和微体古生物化石等资料，一致反映出巴罗地区过去４５０年的气候、环境变化过程存在如下３个阶段：１）大约１５４０～１７４０年，为低海面寒冷时期；２）１７４０～１８２７年，为气候转暖－海侵过渡时期；３）１８２７年至今，为继续海侵－气候波动变暖时期。其中１８００年前后和１９４０年前后，气温较高。１９２１～１９９３年巴罗的气温记录说明，北极地区气温不仅有明显的１０ａ和６０ａ周期变化，而且年平均温度变幅极大，达４．５℃。显示极地气候变化特别强烈并不反映大幅度升温。近２０年来的变暖趋势是１８２７年以来自然的气候波动变暖的继续。     

A Study on Organic Inclusions in Clastic Reservoir Rocks and Their Application to the Assessment of Oil and Gas Accumulations

Terrigenous clastic reservoir rocks are widespread in China,and nearly all the industrial oil and gas accumulations in eastern China occur in the clastic rocks.The study shows that organic inclusions are mostly distributed in the secondary fissures and pores which were ormed in the process of oil-rock interaction,rather than in the cements or secondary enlargements. The organic inclusions are dominantly organic gas-rich or are composed of pure hydrocarbons.Homogenization temperatures range mainly from 120℃ to 130℃，which shows a relatively high maturity of organic matter.Vertical and horizontal temperature changes provide the grounds for the investigation of basin evolution and thermal fluid-kinetics-model.Fluorescence spectral characteristics o the organic inclusions indicate that oils and gases in the area studied probably have experienced two-stage or two-time migration.Micro-fluorescence rescearch is one of the effective approaches to oil/source correlation and oil migration-stage determination.The abundance and occurrence of organic inclusions is one of the indicators of oil and gas abundance and accumulation in rock layers.With the help of other informatio,organic inclusions can provide the basis for the prospective assessment of oil and gas in clastic reservoir rocks.     

The Influence of Element Diffusion at the Sediment—Water Interface on the Basic Chemical Composition of Overlying Water Mass in Lake Lugu,China

Little work has been done on the influence of seiments on the basic chemical composition of overlying water mass.This paper deals with the vertical profile of the basic constituents such as Ca^ ,K^ ,Na^ ,and HCO3^-,as well as of pH in the overlying water mass and sediment porewater of Lake Lugu-a semi-closed,deep lake in Yunnan Province.The reand sediment porewater of Lake Lugu- a semi-closed,deep lake in Yunnan Province.The results revealed that those basic constituents may diffuse and transport from bottom sediments to overlying water mass through porewater.In the paper are also quantitatively evaluated the diffusive fluxes and the extent of their influence on overlying water mass,indicating that the lake sediment-water interface diffusion plays an important role in controlling the basic chemical composition of water in the whole lake.     

Size of a debris flow deposition: model experiment approach

 The prediction of the dangerous extent of a debris flow deposition is of vital importance, but difficult to achieve. Precise prediction of the depositional boundary of a debris flow event is impossible, but the size of a debris flow deposition could provide some estimates of the area, length, width, and thickness of a debris flow deposition. Based on in situ depositional experiments performed on a debris flow creek just after debris flows, a rule of thumb expressed by a group of equations containing the multiple-variate nonlinear functions is proposed in this paper. The interrelationships between the size and the causation also are discussed, and some empirical formulae to calculate the causative parameters for different regions are presented. Received: 24 April 1995 · Accepted: 21 June 1995     

Oxygen isotope fractionation in zinc oxides and implications for zinc mineralization in the Sterling Hill deposit, USA

Oxygen isotope fractionation in the zinc oxides has been calculated by means of the modified increment method. The results suggest that zincite is slightly enriched in ¹⁸O relative to the franklinite of the spinel-type structure but considerably depleted in ¹⁸O relative to the franklinite of the inverse spinel-type structure. The zinc oxides are significantly depleted in ¹⁸O relative to water under hydrothermal and metamorphic conditions. The oxygen isotope analyses of mineral pairs including the zinc oxides and the common gangue minerals such as calcite and quartz can constitute a sensitive isotope geothermometer. Application of oxygen isotope geothermometry to natural assemblages is attempted for the calcite-zinc ore mineral pairs from the Sterling Hill deposit in USA. The results indicate that the temperature of the zinc mineralization may be in the range from 410° to 630 °C and thus lower than the metamorphic temperatures of granulite facies. A metamorphic fluid could have been involved in the formation of the zinc ore minerals. Franklinite would structurally be an inverse spinel in the infancy of its formation, and thus could have originally evolved from Zn^{2 +} substitution to Fe^{2 +} of magnetite at the high temperatures.     

西藏东部南迦巴瓦地区变质作用特征

西藏东部的南迦巴瓦地区包括喜马拉雅地体、中缅地块和印度河－雅鲁藏布江缝合带的一部分。根据区内构造特点、变质岩共生组合、时空分布、矿物共生组合及其反应关系的研究，揭示了本区变质作用特征。南迦巴瓦群发育了一套较完整的递增变质带，经历了先升压后升温的演化过程；雅鲁藏布江变质岩带经历了一次高压低温变质作用；帕隆群变质作用为一个先升温后升压，温压同时达到高峰的演化过程。     

锦屏Ⅰ级水电站坝区岩体结构面特征研究

本文根据锦屏Ⅰ级水电站坝区体结构面野外调资料，对坝区结构面优势方位、间距、张开度、连通率、隙间充填物及形态特征进行了分析，为坝区岩体分类及其物理力学参数的确定提供了重要依据。     

含油气盆地地球动力学模式

文章讨论了含油气盆地地球动力学模式,其中着重讨论了以下几个问题:(1)沉积盆地地球动力学研究的进展,使得能够提出一种根据盆地所处的板块位置和地球动力学模型进行划分的含油气盆地分类;(2)尽管我们有一些古生代克拉通盆地的地球动力学模式,但其成因机制仍缺乏令人信服的解释;(3)通过大陆内裂谷火山岩化学成分、地温场、构造变形、岩石圈结构以及区域板块构造背景综合分析,我们建立了六种大陆裂谷形成的地球动力学模式;(4)前陆盆地的形成与其周缘造山带密切相关,其地球动力学模式是大陆岩石圈对褶皱冲断带构造负载的挠曲响应;     

Chemical composition and Pb(Ⅱ) binding of dissolved organic matter in a hypersaline lake in China

Dissolved organic matter(DOM) plays a vital role in promoting carbon and nutrient cycling.It is a food source for organisms and controls the migration and transformation of trace metals and other contaminants in aquatic systems. The contributions of aquatic DOM to the environment and ecology of a system are closely related to its abundance and chemical structure. In this study, the chemical composition and binding properties of DOM in a hypersaline lake watershed were investigated for the first ...     

Combined refraction and diffraction models for sea waves over complicated topography and with currents in shallow water

-Combined refraction and diffraction models in the form of linear parabolic approximation are derived through smallparameter method. More strictly theoretical basis and more accuracy in the models than Lozano's (1980) are obtained. Some theoretical defects in Liu's model (1985) with consideration of current are not only found but also eliminated. More strict and accurate models are, therefore, presented in this paper.The calculation results and analysis in applying the models to actual wave field with consideration of bottom friction will be given in the following paper.