Sorption behavior of U(VI), ~(234)U(VI) and ~(238)U(VI) onto fracture-filling clays in Beishan granite, Gansu: Application to selecting the site of high-level radwaste repository in China

Knowing the transport of uranium and radionu-clides through the environment is important for as-sessing the risk posed by long-term disposal of rad-waste. Granitic rocks have been selected as a host-rock type for the first high-level radwaste repository in China. According to the Chinese High-level Rad-waste Management Program, high-level radwaste (HLW) will be buried at 800―1000 m depth in a granitic pluton in Northwest China and, specifically, in the A granitic complex of Beishan area,…     

印度洋大地震与海啸灾害综述

2004年12月26日8时58分,印尼苏门答腊岛附近海域发生M8.7地震（百年以来第5次大地震）,其引发的海啸波及了东南亚和南亚至少10个国家,截至2005年3月5日已造成28万人死亡和重大财产损失.这是自1964年3月以来世界上发生的最强烈地震,此次海啸是1900年以来这一地区发生的最大海啸.叙述了此次地震和海啸的破坏情况以及受灾国的应急救援工作和国际社会的反应.概述了地震海啸灾害及其研究简况.     

Effect of tilt on strong motion data processing

In the near-field of an earthquake the effects of the rotational components of ground motion may not be negligible compared to the effects of translational motions. Analyses of the equations of motion of horizontal and vertical pendulums show that horizontal sensors are sensitive not only to translational motion but also to tilts. Ignoring this tilt sensitivity may produce unreliable results, especially in calculations of permanent displacements and long-period calculations. In contrast to horizontal sensors, vertical sensors do not have these limitations, since they are less sensitive to tilts. In general, only six-component systems measuring rotations and accelerations, or three-component systems similar to systems used in inertial navigation assuring purely translational motion of accelerometers can be used to calculate residual displacements.     

The Rhythm of Earthquake Activity and an Analysis on the Earthquake Tendency of the World, the Chinese Continent and North China

Based on the Morlet complex wavelet transformation, the authors put forward a kind of new method for distinguishing periods of seismic activity and quietude and a new physical thought on the time-dependent wavelet accumulation energy spectrum with periods, the time-frequency distribution of wavelet vibration period spectrum and period-specific wavelet vibration spectrum. By applying the above methods to a time series which is composed of earthquake accumulation energy per year for the world, the Chinese continent and North China,respectively, we obtained some new information about the rhythm of shallow earthquake activity. Considering the historic earthquakes and the rhythm characteristics of current strong earthquake activity, the earthquake tendency in the next years is discussed.     

龙羊峡谷更新世以来气候演变特征及其对拉西瓦水电站坝区花岗岩风化作用的影响

龙羊峡谷为黄河上游水电富矿河谷段，拉西瓦水电站位于龙羊峡谷出口地段，研究龙羊峡谷更新世以来气候演变特征对于探讨拉西瓦水电站坝区自然环境发展演化与工程岩体地质过程浅表生改造均有重要意义。本文在简述了龙羊峡谷形成史之后，通过分析树木年轮法、植物孢粉法、同位素法等所获取的资料，总结了更新世以来龙羊峡地区气候演变特征。分析认为龙羊峡地区更新世以来气候以旱寒为主，这种气候特征对于拉西瓦水电站坝区花岗岩风化作用的影响主要存在于两个方面：温度变化及由此带来的冰劈作用。     

强振幅地震属性分析技术在车排子地区油气检测中的应用

准噶尔盆地西缘车排子地区是目前中石化的有利探区,P2井的突破,加速了该区油气勘探的步伐.为了提高勘探的经济效益,用地震特殊处理手段对有利目标进行预测就显得非常重要和迫切.本文运用强振幅属性分析技术有效地预测了该区的有利目标区,并经实钻证实.强振幅属性分析技术是目前车排子地区油气检测的有效手段.     

红山含黄玉花岗岩的形成时代及其成矿能力分析

对闽西南红山含黄玉花岗岩进行了LAM-ICPMS锆石U-Pb定年以及地球化学对比研究。地球化学分析显示红山花岗岩具有富F和高演化的地球化学特征,富含稀有和有色金属成矿元素,如Sn含量为(15·3~54·0)×10-6,W含量(3·04~14·9)×10-6,Nb含量为(22·5~36·7)×10-6,Ta含量为(3·37~7·31)×10-6,U、Th含量分别(6~30)×10-6和(12·1~36·4)×10-6。与含矿花岗岩的对比研究表明红山花岗岩很可能存在与之有成因联系的Sn、U矿床。地球化学填图显示了元素在空间上的分带变化,指出与红山花岗岩有关的成矿作用最可能发生在岩体的东南端,即116°8′E~116°10′E和25°29′N~25°32′N的区域。锆石U-Pb定年结果表明红山花岗岩形成于印支期(~226Ma),因此,其在形成时代、地质产状和成矿作用上不同于华南大多数形成于燕山晚期的含黄玉花岗质岩石。南岭基底变质岩富含W、Sn、Nb、Ta等成矿元素,它们是华南(特别是南岭地区)含矿花岗岩中成矿元素富集的最主要物质来源。     

Fluid Transfer in High-grade Metamorphic Terrains Intruded by Anorogenic Granites: The Thor Range, Antarctica

A composite intrusive igneous complex in the central mountainrange of Queen Maud Land (Thor Range), Antarctica, displayscharacteristic features of anorogenic granites. A suite of massiveintrusives and various sets of dykes and satellite intrusionsare ferroan, alkalic to alkali–calcic, and weakly peraluminous.An early set of plutons consists of charnockitic alkali-granites;a later group of plutons comprises fayalite Qtz-syenites. Coarsemesoperthite is the dominant mineral in all rocks, quartz isabundant and plagioclase is a minor mineral. Olivine (fayalite)is the characteristic mafic mineral, but subcalcic augite andoccasionally pigeonite or orthopyroxene are present. In mostsamples, amphibole is the dominant mafic mineral and its compositionis close to end-member hastingsite. It contains high concentrationsof F and Cl. Some samples contain igneous fluorite. Thermobarometrysuggests a temperature of 900 ± 25°C and a pressureof 0·4 ± 0·1 GPa for the crystallizationconditions of the pyroxene–olivine assemblages. The solidustemperature of 800–850°C for both suites of plutonicrocks is typical of water-deficient granitic melts. The estimatedlow water activity of 0·3–0·5 at solidusconditions is consistent with the high halogen content of thebulk-rocks and their constituent minerals. In the absence ofan aqueous fluid, the halogens remained in the minerals at thesolidus. Oxygen fugacity stayed below QFM in all igneous rocksabove solidus. This is typical of melts derived from partialmelting of mafic source rocks. The igneous rocks were locallyaffected by at least three distinct episodes of hydration. Asthe melt approached solidus conditions, fayalite and pyroxenewere locally transformed into hastingsite as a result of increasingfugacity of volatile components. Fayalite-free and fayalite-bearingigneous rocks are arranged in banded structures. Subsolidushydration locally modified the igneous rocks and transformedpyroxene- and fayalite-bearing granites into biotite-granitesand hornblende-granites in which all evidence of former high-Thistory was erased. This local hydration of igneous rocks occurredin response to uptake of H₂O that had been given off by gneissicxenoliths as a result of progressing, continuous, dehydrationreactions. The reactions in the gneiss xenoliths were drivenby contact metamorphism. This exchange of H₂O between igneousand metamorphic rocks occurred in a fluid-absent regime at temperaturesof about 750°C. Late reaction veins formed by hydraulicfracturing of the plutonic rocks and indicate the presence ofa low-density fluid phase at amphibolite facies conditions. KEY WORDS: anorogenic granite; fayalite; hastingsite; fluid recycling; Antarctica     

Strong Ground Motion Estimation During the Kutch, India Earthquake

In the absence of strong motion records, ground motion during the 26^th January, 2001 Kutch, India earthquake, has been estimated by analytical methods. A contour map of peak ground acceleration (PGA) values in the near source region is provided. These results are validated by comparing them with spectral response recorder data and field observations. It is found that very near the epicenter, PGA would have exceeded 0.6 g. A set of three aftershock records have been used as empirical Green's functions to simulate ground acceleration time history and 5% damped response spectrum at Bhuj City. It is found that at Bhuj, PGA would have been 0.31 g–0.37 g. It is demonstrated that source mechanism models can be effectively used to understand spatial variability of large-scale ground movements near urban areas due to the rupture of active faults.