安宁河-则木河-小江断裂带闭锁特征研究     

宋剑  杨少敏  王伟  黄勇  林牧 《大地测量与地球动力学》2016,36(6):490

分别利用1999~2007年和2009~2014年多期GPS观测获取的水平速度场数据,采用负位错反演模型,研究安宁河-则木河-小江断裂带的滑动速率和闭锁程度空间分布特征,同时结合历史强震记录,分析这几条断裂的地震危险性。结果显示：1)安宁河断裂和则木河断裂滑动速率受汶川地震影响有所减弱,小江断裂滑动速率在汶川地震后基本保持不变;2)则木河断裂中段和小江断裂的断层闭锁程度受汶川地震影响而显著加强,安宁河断裂、则木河断裂的西昌和巧家以北区域的闭锁程度基本不受汶川地震的影响;3)汶川地震发生前后,安宁河断裂的石棉-冕宁段、则木河断裂的西昌与巧家以北区域和小江断裂的通海-建水段闭锁深度均在20 km以上。结合历史强震记录和其他方法的研究结果,三者在未来一段时间内发生强震的危险性要高于其他断层段。  相似文献   

Time-Based Network Analysis Before and After the M_w  8.3 Illapel Earthquake 2015 Chile     

Denisse Pastén  Felipe Torres  Benjamín Toledo  Víctor Muñoz  José Rogan  Juan Alejandro Valdivia 《Pure and Applied Geophysics》2016,173(7):2267-2275

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The role of cytochrome P4501A activity inhibition in three- to five-ringed polycyclic aromatic hydrocarbons embryotoxicity of marine medaka (Oryzias melastigma)     

Mu JL  Wang XH  Jin F  Wang JY  Hong HS 《Marine pollution bulletin》2012,64(7):1445-1451

The mode of action of PAHs that causes fish developmental malformations is unclear. The embryotoxicity of marine medaka (Oryzias melastigma) was investigated after individual exposure to three- to five-ring PAHs Phe, Py, and BaP or co-exposure with α-ANF for 18 days. We found that the relationships between EROD induction and developmental deformities of embryos showed a various pattern under different exposure scenarios of Phe, Py, and BaP, which suggested possibly different modes of action in determining the developmental toxicities. As for co-exposure scenarios of each PAH combined with ANF, it showed potentially synergistic effects. The inhibited CYP1A mediated enzyme activity by ANF after co-exposure did not effectively alleviate developmental toxicity of embryo. It showed potentially synergistic effects after co-exposure of marine fish embryos to CYP1A inhibitors and PAH-type CYP1A inducers. Heart deformities in the early life stages of marine medaka were recommended as a biomarker for indicating the extent of PAH pollution.  相似文献   

Mutations in exons of the CYP17-II gene affect sex steroid concentration in male Japanese flounder (Paralichthys olivaceus)     

Ruiqin Ma  Feng He  Haishen Wen  Jifang Li  Bao Shi  Dan Shi  Miao Liu  Weijie Mu  Yuanqing Zhang  Jian Hu  Weiguo Han  Jianan Zhang  Qingqing Wang  Yuren Yuan  Qun Liu 《中国海洋大学学报(英文版)》2012,11(1):99-104

As a specific gene of fish,cytochrome P450c17-Ⅱ(CYP17-Ⅱ) gene plays a key role in the growth,development and reproduction level of fish.In this study,the single-stranded conformational polymorphism(SSCP) technique was used to characterize polymorphisms within the coding region of CYP17-Ⅱ gene in a population of 75 male Japanese flounder(Paralichthys olivaceus).Three single nucleotide polymorphisms(SNPs) were identified in CYP17-Ⅱ gene of Japanese flounder.They were c.G594A(p.G188R),c.G939A and c.G1502A(p.G490D).SNP1(c.G594A),located in exon 4 of CYP17-Ⅱ gene,was significantly associated with gonadosomatic index(GSI).Individuals with genotype GG of SNP1 had significantly lower GSI(P < 0.05) than those with geno-type AA or AG.SNP2(c.G939A) located at the CpG island of CYP17-Ⅱ gene.The mutation changed the methylation of exon 6.Indi-viduals with genotype AA of SNP2 had significantly lower serum testosterone(T) level and hepatosomatic index(HSI) compared to those with genotype GG.The results suggested that SNP2 could influence the reproductive endocrine of male Japanese flounder.How-ever,the SNP3(c.G1502A) located in exon 9 did not affect the four measured reproductive traits.This study showed that CYP17-Ⅱ gene could be a potentially useful candidate gene for the research of genetic breeding and physiological aspects of Japanese flounder.  相似文献   

Hydrological thresholds of soil surface properties identified using conditional inference tree analysis     

Matthew Tighe  Carlos Muñoz‐Robles  Nick Reid  Brian Wilson  Sue V. Briggs 《地球表面变化过程与地形》2012,37(6):620-632

There has been limited success in determining critical thresholds of ground cover or soil characteristics that relate to significant changes in runoff or sediment production at the microscale (<1 m²), particularly in semi‐arid systems where management of ground cover is critical. Despite this lack of quantified thresholds, there is an increasing research focus on the two‐phase mosaic of vegetation patches and inter‐patches in semi‐arid systems. In order to quantify ground cover and soil related thresholds for runoff and sediment production, we used a data mining technique known as conditional inference tree analysis to determine statistically significant values of a range of measured variables that predicted average runoff, peak runoff, sediment concentration and sediment production at the microscale. On Chromic Luvisols across a range of vegetation states in semi‐arid south‐eastern Australia, large changes in runoff and sediment production were related to a hierarchy of different variables and thresholds, but the percentage of bare soil played a primary role in predicting runoff and sediment production in most instances. The identified thresholds match well with previous thresholds found in semi‐arid and temperate regions (including the approximate values of 30%, 50% and 70% total ground cover). The analysis presented here identified the critical role of soil surface roughness, particularly where total ground cover is sparse. The analysis also provided evidence that a two‐phase mosaic of patches and inter‐patches identified via rapid visual assessment could be further delineated into distinct groups of hydrological response, or a multi‐phase rather than a two‐phase system. The approach used here may aid in assessing scale‐dependent responses and address data non‐linearity in studies of semi‐arid hydrology. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

福建紫金山矿集区浸铜湖花岗斑岩的成因及构造意义     

张倩  吴湘滨  杨牧  钱美平  刁谦  孟斐斯 《现代地质》2019,33(5):1025-1035

华南中生代花岗岩成因研究对指示华南岩石圈演化机制具有重要意义,也是成岩成矿作用研究的重要内容。利用原位LA-ICP-MS锆石U-Pb年代学、微量元素及Hf同位素组成分析,对紫金山矿田内浸铜湖铜钼矿床发育的花岗斑岩开展研究,获得其成岩年龄为(101.1±1.9)Ma,属早白垩世。浸铜湖花岗斑岩锆石Hf同位素εHf(t=101 Ma)为-6.1~0.7,两阶段Hf模式年龄(TDM2)为1.09~1.51 Ga,不支持其形成于华夏陆壳基底物质或壳源(变质)沉积岩的直接熔融。锆石Ce4+/Ce3+值指示岩浆氧逸度较低,表明其成因类似于华南分异的I型花岗岩,主要源于火成岩的部分熔融作用,可能有少量地幔物质的加入。华南晚中生代古太平洋板块受俯冲作用影响,发育大规模岩浆活动,其构造背景为活动大陆边缘环境。  相似文献   

新疆西准噶尔北部布尔津县木斯塔巴岩体年代学、地球化学特征及地质意义     

滕宇翔  薛晓峰  穆利修  朱志新  夏静福 《新疆地质》2019,(3):296-302

准噶尔是新疆北部古生代造山带的重要组成部分,以广泛发育晚古生代花岗岩为特征,是中亚造山带总显生宙陆壳生长作用非常显著的地区之一。根据最新获得的LA-ICP-MSU-Pb锆石年龄,木斯塔巴岩体锆石年龄为(303±2.0) Ma(晚石炭世),岩石地球化学分析,岩石具高硅(66.04%~70.4%),高碱(2.26~2.87),高铝(13.25%~15.46%),高钾(3.4%~4.58%),低镁,A/CNK=1.06~1.22,低固结(6.34~12.87),高分异(78.35~84.5),富轻稀土(LREE/HREE=3.57~12.97)和大离子亲石元素K,Rb,Ba,Sr,亏损高场强元素Nb,Ta,Ti,P,为过铝质高钾钙碱性系列花岗岩,具碰撞花岗岩特征,属额尔齐斯构造带的重要组成部分,其形成与板块俯冲作用关系密切。本区石炭纪花岗岩的数据与北准噶尔地区对比,显示晚石炭世额尔齐斯构造带闭合,进入后碰撞阶段。  相似文献   

城市扩张对东莞市陆表温度的影响分析   总被引：2，自引：0，他引：2  

冯徽徽  刘慧平  朱寿东  白穆 《地理与地理信息科学》2010,26(3)

利用1995年12月30日、2003年1月10日两期Landsat TM/ETM遥感影像反演东莞市陆表温度(LST),分析东莞市陆表温度的总体情况及时空特征,并通过引入温度植被指数(Temperature-Vegetation Index,TVX)空间方法,研究城市化对陆表温度的影响.结果表明:城市化进程是导致东莞市陆表温度上升的重要原因,这种作用在TVX空间中主要体现在聚类点由高植被覆盖-低温度向低植被覆盖-高温度区域的运动过程.  相似文献   

Thermal-mechanical Influences and Environmental Effects of Expressway Construction on the Qinghai-Tibet Permafrost Engineering Corridor     

Ma Wei  Mu Yanhu  Xie Shengbo  Mao Yuncheng  Chen Dun 《地球科学进展》2017,32(5):459-464

The Qinghai-Tibet Engineering Corridor (QTEC) is a strategic passage between Tibet and central China. In the past half century, several major projects have been built in this narrow corridor with vulnerable geoenvironment. Along with a new round of economic development of the Tibet autonomous region, some major linear projects including expressway, double-tracking railway, high voltage power transmission line have been incorporated into the national development planning within the corridor, and especially the expressway construction is imminent now. In the QTEC, permafrost is a controlling factor of geological environment, which will impose great restrictions on engineering construction. In turn, engineering construction will induce significant effects on permafrost geological environment. With more and more linear infrastructures crowding into the QTEC, the thermal interaction among permafrost engineering and engineering disturbance on permafrost thermal-mechanical regime will be more significant. With respect to this issue, a research program focusing on thermal-mechanical influences and environmental effects of expressway construction on the Qinghai-Tibet permafrost engineering corridor was started and supported by the National Natural Science Foundation of China. In this paper, the research significance, key scientific issues, main research contents and goals of the program are introduced so as to provide some references for related researchers and engineers.  相似文献   

扇三角洲沉积储层特征与定量评价——以辽河西部凹陷某试验区于楼油层为例     

陈欢庆  穆剑东  王珏  邓西里 《吉林大学学报(地球科学版)》2017,47(1)

随着蒸汽吞吐开采方式进入后期,储层非均质性对开发效果的影响日益凸显。以辽河西部凹陷某试验区为例,综合岩心、镜下薄片、测井、分析测试等多种资料,实现储层发育特征表征。研究区目的层属扇三角洲前缘沉积,由于水下分流河道的频繁分流改道,砂体相互切叠,储层非均质性强烈。优选充分反映储层性质影响因素的参数,基于经典的聚类分析软件平台,实现扇三角洲沉积储层定量评价。将目的层储层划分为Ⅰ类、Ⅱ类、Ⅲ类和Ⅳ类4种类型,储层分类正判率超过85%。不同类型储层发育明显受沉积相控制,Ⅰ类和Ⅱ类储层多位于水下分流河道和河口砂坝的位置,而Ⅲ类和Ⅳ类储层多位于水下分流河道间砂或前缘席状砂的位置。不同类型储层在转换热采方式时应该区别对待。  相似文献