登山揽月伏蛟龙——施雅风先生对我国泥石流科学研究事业的贡献

2011年2月13日18时35分,我国杰出的地理学家、中国科学院院士、中国现代冰川、冻土、泥石流科学的开拓者和奠基人施雅风先生离开了我们。施雅风院士是我国泥石流研究的奠基人,对我国泥石流科学研究事业的开创、发展倾注了大量心血,培养了大批研究人才,为我国成为世界泥石流研究强国作出了卓越的贡献。从1963年9—10月他率队开始考察西藏波密古乡冰川泥石流,至2011年1月发表庐山泥石流和第四纪冰川的讨论文章,施先生研究泥石流近半个世纪。施先生去世后,作为泥石流研究者,作为施雅风先生当年的同事和晚辈,我们搜集和查阅了大量有关泥石流研     

全球能量收支预算

基于新的观测和分析给出全球年平均能量收支预算,以及陆地、海洋的能量收支贡献及其时间变化。     

基于碳、氧同位素分析的翼龙类生态学

Since their discovery, pterosaurs have prompted much discussion about their ecology and feeding habits. Most pterosaur specimens are known from marine deposits (Kellner, 2003), though this may represent a bias towards preservation rather than necessarily a habitat choice. Recent discoveries of terrestrial deposits (e.g. the Yixian Formation) have also yielded numerous pterosaurs and our knowledge of their diversity has increased dramatically in recent years.     

Spatial Variations in Particle Size and Magnetite Concentration on Cedar Beach: Implications for Grain-Sorting Processes, Western Lake Erie, Canada

<正>This study examined spatial variations in the concentration,grain size and heavy mineral assemblages on Cedar Beach(Lake Erie,Canada).Magnetic studies of heavy mineral-enriched,dark-reddish sands present on the beach showed that magnetite(～150μm) is the dominant magnetic mineral.Surficial magnetic susceptibility values defined three zones:a lakeward region close to the water line(Zone 1),the upper swash zone(Zone 2) and the region landwards of the upper swash zone (Zone 3).Zone 2 showed the highest bulk and mass susceptibility(κ,χ) and the highest mass percentage of smaller grain-size(250μm) fractions in the bulk sand sample.Susceptibility(i.e.κandχ) values decreased and grain size coarsened from Zone 2 lakewards(into Zone 1) and landwards (into Zone 3),and correlated with the distribution of the heavy mineral assemblage,most probably reflecting preferential separation of large,less dense particles by waves and currents both along and across the beach.The eroded western section of Cedar Beach showed much higher concentrations of heavy minerals including magnetite,and finer sand grain sizes than the accreting eastern section, suggesting that magnetic techniques could be used as a rapid,cost-effective way of examining erosion along sensitive coastline areas.     

Mean Kinematic Characteristics of Synoptic Easterly Disturbances over the Atlantic

This study investigates the mean kinematic characteristics of the tropical Atlantic easterly disturbances in January-March(JFM),April-June(AMJ),July-September(JAS)and October-December(OND)from 1968-1998.For each season,the preferential tracks of these disturbances in the 3-10-day band periods were computed and spatialized,as well as their associated wavelength,velocity and main period,which lies between 3-5 days and between 6-9 days depending on the track and the season. Two main tracks are highlighted over the Atlantic Ocean.During OND and JFM these two tracks are well separated and located in each hemisphere around 15°S and 12.5°N.From AMJ to JAS these tracks migrate northward;in JAS,they merge into one over the northern tropical Atlantic along 17.5°N.The associated wavelength fields exhibit a meridional gradient,with large wavelengths(greater than 4000 km) around the equator,between 5°N and 5°S,and smaller wavelengths outside of this latitude band(between 2500-3500 km).The phase speed is also found to exhibit poleward decreasing values from 12-6 m s-1. Over the north Atlantic track,6-9-day disturbances were found to occur from January to May and approximately from October to December.From June to September,the 3-5-day waves dominate the synoptic activity.Over the south Atlantic track,between May and August the synoptic variability is mainly explained by the 3-5-day disturbances but from January to April and from September to December both 3-5-day waves and 6-9-day waves can occur.     

越南西北部一个岩溶山地流域的水文地质特征

本文介绍对越南西北部一个岩溶山地流域——Suoi Muoi河流域水文地质特征的初步评价。该流域海拔600～1700m,面积284km~2。出露的石灰岩占整个流域面积的32％。对该流域已进行了各种类型的评价,包括野外地质和水文地质调查、溶洞调查、染色示踪试验、气象和地表水监测等。通过地质研究和溶洞调查在该流域内识别出了主要的活动溶洞/通道系统。尽管这些数据很重要,但据此还不足以对该流域作一个全面的评价。笔者试图根据短期(15个月)的气     

中国云南岩溶地区乃古石林的白云洞

白云洞是云南乃古石林地区一个长达380km的岩溶洞穴,位于昆明东南70km。溶洞通道的总体方向为N110°～120°E,N0°～10°W,裂隙方向为N30°～40°W,N20°～30°W。溶洞发育于厚层的下二叠统栖霞组,水流发育,正处于近潜水位阶段。溶洞沉积中存在大量     

中国大陆上地幔顶部Pn速度结构

利用３９４７３条Ｐｎ射线的走时资料，采用地震层析成象方法反演中国大陆上地 幔顶部Ｐｎ速度结构．反演结果表明，中国大陆Ｐｎ平均速度为８．０ ｋｍ／ｓ，横向速度变化 量从一０．３０ ｋｍ／ｓ至＋ ０．３５ ｋｍ／ｓ．速度超过８．２ ｋｍ／ｓ的地区主要围绕在青藏高原的周边， 如：准噶尔盆地、塔里木盆地、柴达木盆地及四川盆地；速度偏低的地区主要分布在川 滇西部，山西地堑及渤海湾，在雷州半岛及其以北的粤桂交界处可能存在速度低至７．８ ｋｍ／ｓ的低速区，总体看来，构造上稳定的克拉通地台具有较高的Ｐｎ速度，而构造上活动 的地区往往速度较低；挤压环境具有较高的Ｐｎ速度，而拉张盆地或地堑则具有速度低 的特点．在青藏高原东南部，快波速方向呈现旋转变化趋势，这可能与高原物质受印度 板块的碰撞挤压而向东南方向逃逸有关；渤海湾周围也有显著的各向异性，反映了该 地区存在地壳扩张及可能的岩浆活动．     

中国大陆现今地壳运动和构造变形

全球定位系统（ＧＰＳ）揭示的中国大陆现今运动场清晰地表现出了以活动地块 为单元的分块运动特征，不同的活动地块具有不同的运动和变形方式．ＧＰＳ观测到的阿 尔金断裂的左旋走滑速率仅（５．ｌ± ２．５）ｍｍ／ａ，龙门山断裂的挤压缩短速率为（６．７± ３．０） ｍｍ／ａ，华南地块相对于欧亚大陆向东的运动速率是 １１～１４ｍｍ／ａ，这些结果均不支持青 藏高原北部沿主要走滑断裂向东大规模挤出的假说．中国大陆以活动地块为单元的现 今构造变形可能与大陆岩石圈的结构和性质有关，上地壳以脆性变形为主，下地壳和 上地幔以粘塑性的流变为特征，从底部驱动着上覆脆性地块的整体运动．     

日本东海地区再次发生特大地震的概率:根据古地震、板块构造、海啸研究以及微震活动和大地测量新进展的再评估

根据在近年来人们担心发生8级左右特大地震的日本中部东海地区最新获得的有关孕震的地球物理资料,对不久的将来发生地震的概率作了重新评估。评估中用到的许多数据依赖于古地震、海啸研究及GPS大地测量取得的最新成果。用新的维伯尔分布对东海-南海地震带所作特大地震再次发生趋势的分析表明,该地震带特大地震的平均复发周期约为109 a,标准偏差为33 a。这些值与以往的研究(Rikitake,1976,1986;Utsu,1984)结果相差不大。把最近在东海-南海地震带不同部位测到的菲律宾海板块的运动速度考虑进去,得到了板块边界破裂的极限位移。维伯尔分布分析得到的平均极限位移为4.70 m,标准偏差为0.86 m。利用极限位移平均值除以相对板块速度得到骏河湾处的特大地震发生周期为117a。利用海啸研究确定的断层模型检验了该地震带不同部位与特大地震有关的累积地震滑距的增加。结果表明,该地震带特大地震发生模式采用滑动可预测模型要比采用时间可预测模型更为适宜。根据包括GPS观测在内的大地测量工作的最新进展估算的东海地区累积的地壳应变,与根据以上两种模型推测的极限应变相似。利用从以上讨论的4种情况得到的维伯尔分析参数,估算了东海地区...