Holocene palaeoflood events recorded by slackwater deposits along the lower Jinghe River valley,middle Yellow River basin,China   总被引：3，自引：0，他引：3  

Chun Chang Huang  Jiangli Pang  Xiaochun Zha  Yali Zhou  Hongxia Su  Yuzhu Zhang  Hengsong Wang  Hongliang Gu 《第四纪科学杂志》2012,27(5):485-493

Palaeoflood slackwater deposits (SWDs), are the natural record of overbank flooding and are often found within aeolian loess‐soil profiles along the river valleys of the middle Yellow River basin. These pedo‐stratigraphic sequences are studied using a multi‐disciplinarily approach to reconstruct Holocene hydro‐climatic variations. Our field investigations along the lower Jinghe River valley have identified palaeoflood SWDs at several sites along the riverbanks based on sedimentological criteria. Analytical results, including magnetic susceptibility, particle‐size distribution and concentrations of chemical elements, indicate that these well‐sorted palaeoflood SWD beds were deposited from the suspended sediment load in floodwaters. We identify two episodes of extraordinary palaeoflood events along the Jinghe River valley. These hydro‐climatic events were dated to 4200–4000 and 3200–2800 a BP, by using the optically stimulated luminescence method in combination with archaeological dating of retrieved anthropogenic remains, and with pedo‐stratigraphic correlations with the previously studied Holocene pedo‐stratigraphy in the Jinghe River drainage basin. The flooding events are therefore considered to be a regional expression of known climatic events in the northern hemisphere and demonstrate Holocene climate was far from stable. This study provides important data in understanding the interactions between regional hydro‐climatic systems and global change in semi‐arid and sub‐humid regions. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

山东东营凹陷新近系地层水化学场特征及油气意义^*   总被引：1，自引：0，他引：1       下载免费PDF全文

陈中红  王书南  王黎  查明 《古地理学报》2012,14(5):685-694

为揭示中国东部新生代浅部地层水化学场响应及油气意义,在东营凹陷新近系试油资料统计分析的基础上,对东营凹陷新近系的水化学场特征进行了研究。结果表明,与古近系沙河街组三段与四段封闭性滞留型水化学场特征明显不同,新近系馆陶组和明化镇组总体以低矿化度的NaHCO₃型地层水为主体（矿化度小于5 g/L）;其水化学剖面宏观上具有一定的分带性,大致可以划分为3种水文环境：强开放性水文流畅带(0～0.7km)、弱开放性水文阻滞过渡带(0.7～1.1km)和相对封闭性水文迟缓带(＞1.1km);在不同的水化学作用带,水岩作用和地层水矿化度、离子和离子参数具有不同的响应;东营凹陷新近系Ca相对海水富集(Ca_excess)和Na相对海水亏损(Na_deficient)的定量关系Ca_excess≤0.2367Na_deficient-0.6261,显示出明显的钠亏损特征,钙富集量也远低于世界盆地流体线(Basin Fluid Line,BFL;Davisson,1996)所代表的富集量,与同凹陷古近系沙三、沙四段封闭性水文地质系统中钠相对富集特征也明显不同,反映了地层水蒸发浓缩作用弱及与地表水交替活动强烈的水文地质作用特征;地层水化学场的分布影响了原油密度和天然气的分布规律,使得东营凹陷新近系原油密度与天然气相对密度在剖面上的分布规律与地层水分有良好的一致性。  相似文献   

Integrating ecological damages into the user charge for land reclamation: a case study of Xiamen, China   总被引：1，自引：0，他引：1  

Benrong Peng  Weiqi Chen  Huasheng Hong 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(3):341-351

Land reclamation has become one of the great concerns of many coastal states for its serious environmental and ecological effects. User charge is an effective market-based approach for regulating land reclamation. The user change should be designed to reflect the full effect of converting sea to land to ensure sustainable use of marine resources. In this paper, we present an ecological-economic framework to estimate the user charge that covers both the ecological damages and the rent associated with the reclaimed land. We apply the framework to Xiamen’s West Sea. Results of the case study suggest that the rents of reclaimed land for industrial and commercial uses are 49 yuan/m² and 1,066–2,704 yuan/m², respectively. The unit value of ecological damages of land reclamation is 605 yuan/m². The present user charge is too low to regulate excessive land reclamation. The user charge for land reclamation in the study area should be modified to 653 yuan/m² for industrial uses and 35–40% of adjacent land prices for commercial uses.  相似文献   

Evolution of a coastal upwelling event during summer 2004 in the southern Taiwan Strait   总被引：3，自引：0，他引：3  

ZHANG Caiyun  HONG Huasheng  HU Chuanmin  SHANG Shaoling 《海洋学报(英文版)》2011,30(1):1-6

A coastal upwelling event in the southern Taiwan Strait (STWS) was investigated using intensive cruise surveys (four repeated transects in a month) and satellite data in July and early August 2004.The extensive upwelling-associated surface cold water was first observed in early July (～2.0×10 4 km 2) along the STWS coast.Then,the cold surface water reduced in size by ～50% with decreased chlorophyll concentrations after 15 days,indicating the weakening of the upwelling event.At the end of July,the cold surface water disappeared.The temporal variations of the surface cold water and the 3-D hydrography around Dongshan Island are thought to be mainly attributed to the weakened upwelling-favorable southwestern wind,the asymmetric spatial structure of the wind field and the intrusion of warm water from the northern South China Sea.  相似文献   

新疆北部石炭系构造背景及演化     

匡立春  张越迁  查明  陈中红  李林  孔玉华  张勇 《地质学报》2013,87(3):311-320

新疆北部石炭系洋陆转换过渡期,经历了以下两个演化阶段：早石炭世碰撞间歇期伸展－残留洋闭合、陆-陆碰撞阶段和晚石炭世碰撞期后伸展垮塌－板内变形作用阶段。根据石炭世的板块构造活动背景分析,结合区域构造－沉积岩石组合,初步拟定新疆北部早石炭世原型盆地类型主要包括5类：残留洋、陆缘坳陷、裂陷槽、裂谷、陆内坳陷;晚石炭世原型盆地可简要分为３类：裂陷槽、陆缘坳陷、裂谷或断陷。根据上石炭统原型盆地后期叠加改造特征,将新疆北部现今保存在覆盖区内的上石炭统残留盆地及其叠加改造类型分为两大类六亚类：首先根据是否存在二叠系分为继承型和叠加型两大类,然后再根据中生代及新生代盆地叠加特征分为五亚类,分别为连续继承型、早继承早叠加型、早继承晚叠加型、三叠系叠加型、侏罗系叠加型及白垩系叠加型。  相似文献   

新疆西准噶尔萨尔托海蛇绿混杂岩形成时代及构造环境分析          下载免费PDF全文

何世平  时超  王超  于浦生  辜平阳  查显锋 《地质科学》2013,48(4):1033-1049

萨尔托海蛇绿混杂岩是西准噶尔地区达拉布特蛇绿混杂岩带的重要组成部分,其形成时代和构造环境颇具争议。通过LA-ICP-MS锆石微区原位U-Pb同位素测年,获得其中辉长辉绿岩的 ²⁰⁶Pb/²³⁸U 加权平均年龄为388.8±1.1 Ma,确定该蛇绿混杂岩形成于中泥盆世。岩石地球化学分析表明,纯橄岩(蛇纹岩)属于低Si、低碱、高Mg的变质橄榄岩,REE呈∑REE 偏低的平坦型分布模式,Cr、Ni和Co含量较高,变玄武岩属于高Ti、富Mg、富Fe、偏碱的拉斑系列,REE分布模式呈现 ∑REE 偏低、Eu异常不明显的平坦型曲线,微量元素分布模式为K、Cs、Th、Nb和P相对亏损的平坦型曲线,Zr/Nb比值低,总体表现出与E-MORB相似的特征。综合判断认为,萨尔托海蛇绿混杂岩形成于大陆裂谷向洋盆转化的构造环境,类似于"红海式"洋盆,为进一步深入认识新疆地区众多蛇绿混杂岩的形成构造环境提供了新思路。  相似文献   

冬春500hPa高度场与中国夏季降雨场的场相关分析   总被引：11，自引：1，他引：11  

琚建华  邓崧  陈兴芳  严华生 《热带气象学报》1999,15(2):154-161

利用场相关理论，分析了中国大陆6－8月降水场与前期1－5月各月北半球500hPa高度切之间的关系，得到一些有意义的结果，并提出一种研究场与杨之间相关关系的长期天气预报思路和方法。  相似文献   

辽宁及邻区电磁辐射在地震中的应用研究     

张颖  楂楠 《国际地震动态》2009,(7):47-53

通过省内、省外台站分布情况、台址情况、观测记录仪器使用情况,观测记录仪器的性能指标,如观测仪器探头类型、架（埋）设方式,记录仪器的采样率、分辨率,震例情况等从电磁辐射的发生机理出发进行深入细致的分析,找出地震前电磁辐射异常信息量、异常起始时间及持续时间与震中距、震级的关系。  相似文献   

柴达木盆地西部第三系蒸发岩与生油岩共生沉积作用研究   总被引：44，自引：3，他引：41       下载免费PDF全文

金强  查明 《地质科学》2000,35(4):465-473

许多人认为柴达木盆地第三纪盐湖环境不利于形成有机质丰度高的优质生油岩.作者通过柴达木盆地西部下干柴沟组、上干柴沟组(E₃和N₁)蒸发岩沉积成因和生油岩有机质富集状态的研究,发现优质生油岩(TOC>1%,干酪根类型为Ⅰ型或Ⅱ₁型)恰好发育在石膏、芒硝和岩盐最发育的构造部位和层位,提出了一种"大咸盆套小盐湖"的蒸发岩与生油岩共生的沉积模式,认为第三纪盐湖的水体深浅既控制了蒸发岩沉积和分布,又控制了一般生油岩和优质生油岩的形成,就该盐湖有机质分布规律进行了理论解释.  相似文献   

近岸海域光合色素的生物标志作用研究：Ⅰ.台湾海峡特征光合色素的分？…   总被引：4，自引：1，他引：3  

王海黎  洪华生 《海洋学报》2000,22(3):94-102

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