东南地洼区的地球物理特征及其深部构造力源机制探讨

本文较全面地探讨了东南地洼区反映深部构造特点的地球物理特征(波速结构,地温分布,电性,密度,重、磁场异常),综合分析了该区地洼构造形成、演化的力源机制,讨论了地洼构造与板块构造的力源机制关系问题。     

Spatiotemporal patterns of road network and road development priority in three parallel rivers region in Yunnan, China: An evaluation based on modified kernel distance estimate

Road network is a critical component of public infrastructure,and the supporting system of social and economic development.Based on a modified kernel density estimate(KDE)algorithm,this study evaluated the road service capacity provided by a road network composed of multi-level roads(i.e.national,provincial,county and rural roads),by taking account of the differences of effect extent and intensity for roads of different levels.Summarized at town scale,the population burden and the annual rural economic income of unit road service capacity were used as the surrogates of social and economic demands for road service.This method was applied to the road network of the Three Parallel River Region,the northwestern Yunnan Province,China to evaluate the development of road network in this region.In results,the total road length of this region in 2005 was 3.70×104km,and the length ratio between national,provincial,county and rural roads was 1∶2∶8∶47.From 1989 to 2005,the regional road service capacity increased by 13.1%,of which the contributions from the national,provincial,county and rural roads were 11.1%,19.4%,22.6%,and 67.8%,respectively,revealing the effect of′All Village Accessible′policy of road development in the mountainous regions in the last decade.The spatial patterns of population burden and economic requirement of unit road service suggested that the areas farther away from the national and provincial roads have higher road development priority(RDP).Based on the modified KDE model and the framework of RDP evaluation,this study provided a useful approach for developing an optimal plan of road development at regional scale.     

地震勘探技术在内蒙古自治区四子王旗德日存呼都格矿区的应用

地震勘探技术以其成本低、效率高的优势在煤田勘探中被广泛的应用。内蒙古自治区四子王旗德日存呼都格矿区采用地震勘探技术,在解释煤层、构造等方面取得了良好的效果,给煤矿的开采设计施工提供了参考依据,为煤炭勘查做出了重要贡献。     

退耕还林对牡丹江区域生态环境脆弱性的影响研究

从脆弱生态系统的特征入手,选取景观分离度、分维数倒数、破碎度3个反映景观稳定性及抗干扰能力的景观格局指数,并结合土壤侵蚀强度构成区域生态环境脆弱性的敏感因子,针对研究区地形,以景观生态适宜度作为生态系统自我恢复能力的表征,构建了牡丹江区域生态环境脆弱度评价模型。评价结果表明:（1）退耕还林前后景观类型脆弱度均表现为旱田>建设用地>水田>林地>未利用土地>水域>沼泽>草地;（2）研究区生态脆弱度表现为以脆弱度高值区为中心呈环状向四周递减的趋势,脆弱度高值区面积比重由退耕前的21.57%减小到退耕后的17.11%,脆弱度低值区面积比重由退耕前的63.14%增加到退耕后的67.66%;（3）生态脆弱度高值区域主要分布在200~400m的海拔高度,0~8°的坡度范围内,且退耕后面积比例呈下降趋势,而低值区域则分布在>300m海拔高度的各个坡度范围内,且退耕后面积比例呈上升态势。研究结果符合研究区实际状况。概言之,退耕还林缓和了研究区生态脆弱度状况,促进了生态环境质量向良好方向发展。     

西藏努日矽卡岩型铜钨钼矿辉钼矿 Re-Os定年及其地质意义

西藏努日层状矽卡岩型铜钨钼矿床是冈底斯东段南缘斑岩-矽卡岩铜多金属成矿带上规模最大的矿床。笔者对采自该矿床的9件不同产状、不同形态含钼矿石中的辉钼矿进行了Re-Os同位素组成分析,获得其模式年龄为23.46~24.77 Ma,等时线年龄为(23.36±0.49) Ma(MSWD=0.60),模式年龄与等时线年龄结果基本一致。由于辉钼矿与黄铜矿、白钨矿呈共生关系,并考虑到该矿区内黄铜矿的年龄〔(23.75±0.18) Ma〕(作者未发表数据),表明努日矽卡岩型铜钨钼矿床的成矿时代为23~24 Ma。结合前人研究资料可见,冈底斯南缘克鲁-冲木达斑岩-矽卡岩铜多金属成矿带从32 Ma至23 Ma发生了强烈的成矿作用。该成矿带的成矿时代明显有别于后碰撞期地壳伸展环境下形成的冈底斯斑岩铜矿带,显示出其为一套独立的成矿事件。该成矿事件可能主要受冈底斯南缘的晚碰撞走滑环境的控制。努日矿床成矿时代的确定及晚碰撞成矿事件的厘定,为今后研究和勘查该成矿带内同类型矿床提供了重要依据。     

Spatial structure and land use control in Extended Metropolitan Region of Zhujiang River Delta,China

The Zhujiang (Pearl) River Delta is one of the most developed Extended Metropolitan Regions (EMR) in China.With the rapid urbanization,the agglomeration of population and industries has emerged,which has led to dramatic changes of spatial structure and land use in this region.With data of high resolution TM remote sensing images and Google Earth maps,this paper identified and analyzed the spatial pattern of the Zhujiang River Delta EMR using Envy and ArcGIS tools.It was found that 1) the industrial land uses were expanding substantially,particularly on the bank sides of the Zhujiang River estuary;2) large-scale housing developments were concentrated in the fringe of metropolitan areas such as those of Guangzhou and Shenzhen;3) a regional transportation network with the spatial pattern of ″1 circle +2 pieces + 3 axes″ had significantly affected the location choice of manufacture enterprises.At the same time,both highly specialized land use and severely mixed land use patterns were identified.As a consequence of the latter,land use efficiency of the whole EMR areas was reduced.Moreover,ecologic and environmental problems were severe.Based on the above analysis,suggestions were given from the viewpoint of spatial safety,land use efficiency,and the reorganization of spatial structure in the Zhujiang River Delta EMR.     

海原西华山地区金矿化的地球化学特征及成因

本文通过微量元素、硫同位素、氧同位素及矿物流体包裹体研究等方法首次对宁夏海原西华山地区金矿化的地球化学特征进行了探讨，提出了地层、构造及岩浆活动三者联合控矿的成因认识。这一认识无疑对宁夏为数不多的有色金属矿化区之一──宁夏海原西华山地区的金矿的找矿预测具有实际意义。     

新特提斯洋晚白垩世演化特点:来自泽当共国日二长花岗岩年代学、地球化学及Sr-Nd同位素证据

为加深对西藏泽当地区新特提斯洋演化的认识,对西藏泽当蛇绿混杂岩带内的共国日二长花岗岩进行了岩石学、岩石地球化学、同位素及年代学等研究,研究显示:共国日二长花岗岩岩体规模小、岩性稳定,LA-ICP-MS锆石U-Pb年龄为(90.40±0.68)Ma,属晚白垩世;岩石地球化学具高硅、富铝、富钾、低钛和准铝质钙碱性花岗岩特征;轻稀土富集、重稀土亏损,具明显的负Eu异常,微量元素表现为相对富集Rb、K、Ba、Th、U等大离子亲石元素,显著亏损Nb、P、Ti等高场强元素;(⁸⁷Sr/⁸⁶Sr)_i=0.705 708~0.706 284,(¹⁴³Nd/¹⁴⁴Nd)_i=0.512 689~0.512 716,ε_Nd(t)=2.00~2.51。以上特征表明,位于泽当蛇绿混杂岩带内的共国日二长花岗岩属于I型花岗岩,由正常岛弧岩浆形成,应为晚白垩世新特提斯洋向北俯冲形成的岛弧环境下俯冲带上部地壳部分熔融的产物,其不属于泽当蛇绿岩的组成部分,表明在90 Ma前泽当洋内弧已经消失。     

藏南也拉香波早渐新世富钠过铝质淡色花岗岩的成因机制及其构造动力学意义

藏南也拉香波穹隆位于近东西向展布的北喜马拉雅片麻岩穹隆(NHGD)最东端,主要由石榴角闪岩、石榴石云母片麻岩、二云母花岗岩和淡色花岗岩组成.SHRIMP锆石U/Pb定年结果表明也拉淡色花岗岩的结晶年龄为35.3±1.1Ma,明显老于位于该穹隆以西类似的淡色花岗岩(年龄普遍<25Ma).全岩元素和Sr-Nd同位素测试结果揭示：(1)也拉香波淡色花岗岩为过铝质富钠花岗岩;(2)与片麻岩相似,也拉香波淡色花岗岩富集大离子亲石元素(LILE,如K,Sr,Rb和Ba),但亏损Ti,Y,Yb,Sc和Cr;(3)和片麻岩或角闪岩相比,也拉香波淡色花岗岩同时亏损LREE和HREE,但与HREE相比,LREE相对富集;(4)在Sr-Nd同位素系统特征上.淡色花岗岩初始Sr同位素比值与角闪岩的相当,在0.711949～0.719344之间;但远小于片麻岩.而Nd同位素组成在片麻岩和角闪岩之间,在-8.9～-15.0之间.以石榴角闪岩和片麻岩为端元,简单混合计算表明：由石榴角闪岩为主和片麻岩为辅组成的混合源区发生部分熔融作用,各自产生的熔体进行不同程度的混合,可形成类似于也拉香波淡色花岗岩成分的岩浆,其中角闪岩的部分熔融起主要作用.使用Zr在岩浆中的饱和浓度温度计得出岩浆的平均温度为673℃,在此温度下,变泥质片麻岩在高压(～10kbar)条件下的水致部分熔融和角闪岩部分熔融都可形成也拉过铝质富钠淡色花岗岩,但角闪岩的脱水部分熔融起主导作用.在地壳增厚条件下,下地壳角闪岩的部分熔融可能是导致喜玛拉雅造山带从缩短增厚向伸展垮塌转换的主要因素之一.     

太阳大气中氢原子的赖曼谱线

氢是太阳大气中最主要的元素。氢原子的赖曼(Lyman)谱线,尤其是赖曼阿尔法(Ly-α)谱线的辐射,是太阳色球和低过渡区能量损失的主要形式。在太阳的赖曼α像中,网络组织的辐射比较强,而辐射最强的地方是活动区。由于存在辐射转移效应,在宁静区,低阶赖曼谱线的谱形中央一般会形成一个凹陷,而在中央两侧则形成两个峰,两峰往往呈现出一定的不对称性。数值模拟和观测研究表明,赖曼谱线双峰的不对称性与高层大气中各种系统性流动有关。在太阳活动区,赖曼谱形在谱斑区与在宁静区类似;而在黑子区,赖曼谱形几乎没有中央凹陷。赖曼谱形也可用于诊断日珥、耀斑和日冕物质抛射等结构和现象的等离子体特性。该文回顾了赖曼谱线的观测历史,阐明了观测与模拟结果所揭示的物理过程,并结合笔者的认识进行了相应的评论。