上海地区更新统承压含水层沉积机制（模式）探讨   总被引：3，自引：0，他引：3  

黄建国  吴惠兰 《上海国土资源》1992,(2):15-23

区内更新世古河道变迁,具有暖期向南摆动,冷期向北摆动的规律。一、三期古河道暖期向南摆,河床中沉积的砂层形成了含水层,其间所夹持的隔水层(粘土、亚粘土)是二期古河道冷期向北摆动时的边滩或心滩沉积,从而形成了含水层与隔水层。无论是冷期或暖期的古河道都形成各自的含水砂层及隔水牯土、亚粘土层。对暖期形成含水层,冷期形成隔水层的看法,笔者认为值得商榷。  相似文献   

鲁西北52年日照变化特征及原因   总被引：23，自引：0，他引：23  

石慧兰  王新堂  邵志勇  陈成国  刘春红 《气象》2007,33(2):93-97

通过分析德州市1954-2005年日照、云量、霾、雾、沙尘等资料，用最小二乘法计算气候倾向率。结果表明，德州市日照时数平均10年减少105．0小时，日照百分率平均10年降低2．4％。总云量平均10年减少0．03戍。沙尘暴、扬沙、浮尘日数呈明显减少趋势。低云量和霾、轻雾、雾日数呈增加趋势，尤其是自1990年代中后期明显增加，与德州市自1990年代中期开始经济规模快速增长相对应，说明鲁西北日照减少主要是由于低云量增加和人类活动特别是工业排放污粢物急剧增长导致的大气气溶胶增多造成。  相似文献   

湘西—鄂西地区铅锌矿的大范围低温流体成矿作用研究          下载免费PDF全文

周云  段其发  曹亮  李芳  黄惠兰 《高校地质学报》2014,20(2):198

对湘西—鄂西地区狮子山、李梅、耐子堡、茶田、打狗洞、董家河、唐家寨、冰洞山、凹子岗等典型铅锌矿床中闪 锌矿、方解石、白云石及石英等矿物进行了流体包裹体均一温度、盐度、流体包裹体气相成分、流体包裹体群体液相成分 测定,结果表明:成矿流体温度主要分布在 80~230 °C,总盐度一般>15%,密度多>1g/cm3,成矿压力为 223×105~777× 105 Pa,是以钠和钙氯化物为主的高浓度溶液,属于低温度、高盐度、高密度的地下热卤水性质的含矿热水溶液。成矿流体 阳离子成分主要为 Cl-, Na+, Ca2+, K+, Mg2+,流体包裹体氢氧同位素组成表明成矿流体来源与建造水有关,后期可能有雨水和 少量变质水的渗入。矿物流体包裹体中含有机质,流体包裹体气相成分中 CH4 普遍存在,表明成矿与有机质相关,处在控 矿构造内容矿层中的有机质使矿床中的硫酸盐硫还原为还原硫,促使成矿流体中的铅、锌沉淀形成矿床。相邻的低温成矿 域川滇黔地区典型铅锌矿床成矿温度约为 90~280°C,湘西—鄂西地区铅锌矿与川滇黔铅锌矿相比,具有相同的低温成矿特 征,矿床类型均为 MVT 型,两者可能受控于相同的动力学背景。  相似文献   

Receiver functions of CCDSN and crustal structure of Chinese mainland          下载免费PDF全文

Xuzhang Shen  Huilan Zhou 《地震科学（英文版）》2012,25(1):3-16

The teleseismic receiver functions of 48 stations belonging to the CCDSN are used to invert the crustal structure beneath each station with the neighborhood algorithm. Thin layers with low velocity have been found beneath eight stations with "abnormal" observed receiver functions. Unreasonable results of few stations have been adjusted lightly with the trial-and-error method. The final result indicates that the crust in the western China is relatively thicker than the eastern China. The crust thickness beneath the Tibetan plateau is very large, which reaches 84 km at the station LSA. Double-crust structure exists below the stations LSA and CAD in Tibet, which might imply the collision between the Indian and Eurasian plates. A pronounced low velocity zone in the lower crust beneath the station TNC of Yunnan province might relate to the high temperature or emergence of partially molten material caused by Quaternary volcano, magma and geothermal activities in this area. The Moho is a transitional zone made up of thin layers instead of simple sharp discontinuity beneath several stations. The Conrad discontinuity is clearly identified beneath 20 stations mainly in the southeastern China, whereas it is blurry beneath 14 stations and uncertain beneath remaining stations.  相似文献   

Study on Precipitation Image Downscaling Based on the Method of Ill-posed Problems Solving     

Wang Gen  Sheng Shaoxue  Huang Yong  Wu Rong  Liu Huilan 《地球科学进展》2017,32(10):1102-1111

Downscaling of remote sensing precipitation products and the forecasting of circulation model are always the intense interests in hydrology and meteorology. The essence of downscaling is primarily to enhance resolution of observation or simulated rainfall field, and to appropriately increase its details or high frequency characteristics. Precipitation, as the main driving factors of the earth’s hydrologic cycle, not only affects the moisture and heat condition of a certain river basin, but also affects the global water and heat circulation. Based on the properties of rainfall self-similarity structure, the mathematically ill-posed precipitation problem solving method was used in low resolution downscaling precipitation for high resolution reconstruction. When solving the downscaling ill-posed problem, the greedy method of orthogonal matching pursuit was introduced so as to get the best high-resolution estimation in an optimal sense. It is hard to imagine that we might be able to find very similar (in mathematical norms) precipitation patterns over relatively large storm-scales. However, finding similar features over sufficiently small sub-storm scales seems more feasible. Based on the characteristics that small scale organized precipitation features tend to recur across different storm environments, the precipitation of both high and low resolution was obtained by training, which could be used to reconstruct the desired high-resolution precipitation field. Multi-source merged precipitation products were used in this experiment. Given the consideration of incompleteness of merged precipitation dataset, it was firstly interpolated based on the method of Fields of Experts (FoEs), which could solve the problem that common interpolation method could hardly work on the interpolation for dataset where consecutive missing data exists. Secondly, ideal experiments of precipitation products downscaling were carried out, where smooth coupling sampling and resampling operator were adopted respectively. Assessment based on the metrics of fidelity and spatial structural similarity demonstrates that the method used in this paper is feasible.  相似文献   

ARX结构模态参数识别方法对比(I)——基于理论地震反应时程的对比     

曹会兰  李山有  张雷  李伟 《地震工程与工程振动》2009,29(1)

结构参数识别是结构抗震安全性能鉴定和健康诊断的基础。利用地震观测记录来识别结构模态参数,是地震工程领域备受关注的研究课题之一。本文利用三层平面框架结构的理论地震反应时程,对一维、多维和整体ARX模型三种模态参数识别方法进行了对比分析。结果表明：整体ARX模型的识别结果较为稳定且精度较高,更适合于进行多自由度结构参数识别。  相似文献   

A new species and a new record of free-living marine nematode of genus Diplolaimelloides (Monhysteridae) from Futian mangrove reservation in Shenzhen,China     

Chen  Yuzhen  Zhu  Huilan  Guo  Yuqing 《中国海洋湖沼学报》2023,41(1):314-326

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SS波形复杂性研究          下载免费PDF全文

何小波  周蕙兰  马延路  钮凤林 《地震学报》2008,30(1):36-46

通过使用传播矩阵方法计算全波场理论地震图和对观测资料分析,对40deg;——180deg;震中距范围内SS波形复杂性的影响因素进行了定量探讨. 研究表明,S波在反射点的莫霍面和地表产生的透射转换与反射转换震相,是造成SS波形复杂化的主要因素;反射点莫霍界面两侧的波速差异程度对各转换震相幅度有重要影响. 当反射点地壳比较薄时,台站地壳也对SS波形的复杂化起作用. 这些影响因素共同造成了SS的切向与径向分量之间的分裂时间与反射点地壳厚度具有明显正相关性. 对SS反射点分别落在中国东部和西部的两组观测波形资料进行了分析,并测量了切向与径向之间的分裂时间. 结果表明,地壳较厚的西部的分裂时间明显大于地壳较薄的东部的分裂时间,并有可能发展一种利用SS分裂时间来估算地壳厚度的新方法.   相似文献   

俯冲带中的洋壳在中国东北上地幔底部分离的地震学证据     

沈旭章  周蕙兰 《国际地震动态》2008,(11)

中国东北西太平洋俯冲带位于欧亚板块与西太平洋板块的交界部位,西太平洋板块的俯冲运动从日本海沟开始一直延伸到了中国东北地区.层析成像(Gudmundsson & Sambridge,1998;Huang & zhao,2006)结果表明,西太平洋板块和该区域'660'的相互作用,导致了该区域上地幔结构的复杂性.  相似文献   

云南哀牢山蛇绿岩的矿物学研究   总被引：3，自引：1，他引：2  

凌其聪  程惠兰  沈上越  魏启荣 《矿物学报》1999,19(1):56-62

云南哀牢山蛇绿岩由变橄榄岩、堆晶杂岩、火山熔岩和硅质岩等四个单元组成,其主要矿物有橄榄石,斜方辉石、单斜辉石、尖晶石、斜长石、角闪石、石榴子石等,这些矿物均已不同程度地遭到蚀变、橄榄石、斜方辉石的化学成分显示蛇绿岩中的二辉橄榄岩为原始地幔岩;是石的化学特征表明蛇绿岩中的橄榄岩为深海橄榄岩;单斜辉石的成分反映二辉橄榄岩经历过熔融作用,堆晶杂央才基性熔岩具有火山弧和洋底玄武岩的特征。  相似文献