Hydrochemistry and sediment characteristics of polar periglacial lacustrine environments on Fisher Island and Broknes Peninsula,East Antarctica

Fisher Island and Broknes Peninsula in the Larsemann Hills constitute part of a polar lowland periglacial environment between marine and glacial ecosystems. The landscape is characterized by gently rolling hills and broad valleys interspersed with lakes formed in glacially scoured basins. We analyzed the physieochemical parameters and the ionic constituents of water samples from 10 lakes in each of these two locations. Our results showed considerable differences between the two regions and demon- strated the influence of lithology and processes including weathering, evaporation, and atmospheric precipitation. All major cations and anions in the lake waters showed positive correlations indicating balanced ionic concentrations. Unconsolidated sediments were sparsely distributed and scattered over glacial deposits, valley fills, and occasional moraine ridges. The type and rate of sedi- mentation was mainly controlled by surface run-off and aeolian influx. The sediment samples from lake beds and the catchment area on Fisher Island were immature and poorly to very poorly sorted, consisting of gravelly sand with negligible silt and finer fractions. Sediments had a polymodal grain size distribution with the two major populations lying between -2 and 1 phi and be- tween 0 and 1.5 phi. The sediments were lithic arenite to arkosic in composition and the microtextures imprinted over quartz grains were dominated by mechanical textures resulting from several stages of glacial crushing and grinding. The presence of deep disso- lution cavities, cryptocrystalline precipitation, and euhedral crystal growth signified the effect of chemical activity after the deposition of grains in the lacustrine environment.     

From the editors

<正>Dear JEEEV Contributors, Readers and Friends,This issue of Earthquake Engineering and Engineering Vibration (Vol. 9, No. 3) includes five papers that were presented at the 4th     

太阳γ及β_γ黑子磁埸区大耀斑的地磁效应

本文研究了1938—1958年间,太阳γ及βγ黑子磁場区的3級与3~+級大耀斑的地磁效应。用相关及迴归分析法,計算了太阳赤緯、日軸方位角及耀斑的日面經緯度等因素对于磁扰的彭响。根据分析結果,繪出了日面地磁扰动等值图。利用水手2号飞船上量譜仪測出的太阳风速度和相应的地磁A_p指数,算出了相关关系,并用此和上述日面地磁扰动等值图配合,推算了在耀斑发生以后,太阳风的径向分量沿地球軌道的分布。参考文內各相应的曲线,可以約略估計出耀斑发生后地磁A_p指数的大小。     

根据VLF的相位变化确定D层宇宙线强度变化的可能性

银河宇宙线是电离层D层的重要电离源之一,它的急剧变化会使D层电子密度发生改变,从而影响VLF波的夜间传播。本文根据在西安接收英国GBR台的VLF波（16kc/s）的相位变化,讨论了在有宇宙线暴（Forbush下降）和强磁暴时,中纬D层电子浓度的变化和相应的VLF波的相位漂移;并根据VLF的相位变化,估计了相应的宇宙线强度变化。由于D层中的宇宙线强度变化通常难于观测,通过VLF波的相位漂移来估计它,这是很有意义的。所以,VLF波的传播效应可能成为间接探测宇宙线强度变化的有用工具。     

青海大柴旦石灰沟制碱石灰岩矿床地质及成因

矿体赋存于下奥陶统多泉山组中,矿石类型为泥晶灰岩和含生物碎屑泥晶灰岩,典型的残海生物化学沉积,含CaCO393.69ω％～94.0ω％,理想的制碱石灰岩,受地层控制,矿体稳定易采.     

实施好地质环境保障工程

2006年1月20日．国务院印发了《国务院关于加强地质工作的决定》。《决定》全面分析了我国地质工作面临的新形势．阐述了加强地质工作的重要意义．明确了新时期地质工作的总体要求、基本原则、主要任务及加强地质工作的主要措施．是新时期推进地质工作改革发展的纲领性文件。温     

半潜平台浮子式系泊系统参数优化研究

通过在系泊缆中设置浮子可以改善系泊系统性能,降低平台运动响应。建立浮子式系泊系统的数值计算模型,验证浮子式系泊系统数值计算方法,详细分析浮子设计参数(设置位置和净浮力大小)变化对系泊缆张力特性与平台运动的影响规律,并根据得到的规律选择了优化的浮子系泊系统方案。最后对优化方案进行评估,表明优化方案可以显著降低系泊中的平台水平运动,尤其是低频运动,同时系泊缆张力变化不大,仍满足安全要求。研究结果可为今后浮子式系泊系统设计提供参考。     

规整化标定在地震遥测系统中的应用

规整化标定是模拟观测地震仪器标定的一种方法。系统介绍了规整化标定仪器的方法、参数，发现它有许多优点，是标定遥测地震仪器的一种较理想的方法。