粤西海陵湾养殖区邻近海域大型底栖动物生态学特征   总被引：6，自引：5，他引：1  

李亚芳  杜飞雁  王亮根  宁加佳  李纯厚 《海洋与湖沼》2018,49(6):1294-1307

根据2014—2016年粤西海陵湾养殖区湾内和湾外邻近海域21°27′—21°38′N、111°42′—111°57′E 4个航次调查资料,对其大型底栖动物生态学特征进行了研究。结果表明,共鉴定大型底栖动物64种,春季种类最多为39种,秋季最低为17种。4季均以环节动物种类数最多,软体动物次之。不同季节间优势种有所差异,仅倍棘蛇尾Amphioplus sp.为周年优势种。春、夏、秋和冬季第一优势种分别为倍棘蛇尾、菲律宾蛤仔Ruditapes philippinarum、短吻铲荚螠Listriolobus brevirostris和平蛤蜊Mactra mera。平均丰度和生物量分别为213ind./m~2和15.4g/m~2,其中丰度以春季最高为248ind./m~2,夏季最低为167ind./m~2,而生物量则以秋季最高为28.0g/m~2,春季最低为2.4g/m~2;平面分布总体呈现湾外高于湾内的趋势。底栖动物Pielou均匀度和Shannon-Wiener多样性指数分别为0.95—1.00和1.56—4.07,其中时间分布规律明显,春季最高,秋季最低;空间上,两者无明显分布差异。群落结构时空差异显著,为沉积物类型、水深、底层无机氮和悬浮物以及捕食压力等因素共同影响的结果。  相似文献   

新疆库车县盐水沟北铜矿床地质特征及成因探讨          下载免费PDF全文

刘传朋 《山东国土资源》2018,34(4)

盐水沟北铜矿区位于新疆库车县北部,其大地构造位置处于塔吉克-塔里木陆块区、塔里木陆块、塔里木北缘隆起、库车前陆盆地,区内构造活动强烈。铜矿床赋存于新近纪中新统康村组第一岩性段,矿体呈层状,严格受地层控制。区内共圈定10个铜矿体,矿石矿物主要为孔雀石、赤铜矿、水胆矾、自然铜等,矿体内无夹石,顶、底板围岩均为褐红色及浅红色粉质泥岩。该矿床为砂岩型铜矿床。  相似文献   

车辆荷载作用下山西路基重塑黄土的动力特性研究   总被引：2，自引：0，他引：2       下载免费PDF全文

马林  张军  刘亚明 《地震工程学报》2018,40(1):101-104

针对车辆荷载对山西高速公路路基土体影响研究不足的现状,从试验角度出发,研究车辆荷载水平、波形、干密度和围压对路基土体的动力特性响应。研究表明:路基土体的体变随波形比的增大而增大,随车辆荷载的增大而增大;路基土体的动弹性模量随干密度的增大而增大,随围压的增大而增大,阻尼比随围压的增大而减小。  相似文献   

2014年鲁甸M_S6.5地震后地质灾害发育分布特征          下载免费PDF全文

杨秀元  姚亚辉 《地震工程学报》2018,40(5):1078-1083

2014年云南鲁甸“8·03”M_S6.5地震造成了重大人员伤亡和财产损失，诱发了大量滑坡、崩塌、泥石流等地质灾害。基于对鲁甸县龙头山幅（G48E006006）地质灾害调查数据和对典型地质灾害的剖析，震后地质灾害发育分布有特征如下：（1）震后地质灾害较震前成倍增长，震前地质灾害多以中小型浅层崩滑为主，地震诱发了诸如甘家寨、红石岩等大型—特大型滑坡、崩塌，大量沟谷崩滑堆积物为泥石流储备了丰富的物源；（2）震中高烈度区域地质灾害密度大，沿发震断裂带NNE—NE向构造密集发育，震中区龙头山镇地质灾害发育最为集中；（3）地质灾害呈带状分布，明显受控于河流水系（牛栏江、沙坝河、龙泉河等）、公路（昭巧二级公路、沙乐公路）等线性地貌单元和线性工程，人类活动影响明显。  相似文献   

THREE-DIMENSIONAL DEFORMATION CHARACTERISTICS OF THE XIANSHUIHE FAULT ZONE     

ZHAO Jing  REN Jin-wei  JIANG Zai-sen  Yue Chong 《地震地质》2018,40(4):818-831

In order to analyze 3-dimensional movement and deformation characteristics and seismic risk of the Xianshuihe fault zone, we inverted for dynamic fault locking and slip deficit rate of the fault using the GPS horizontal velocity field of 1999-2007 and 2013-2017 in Sichuan-Yunnan region, and calculated annual vertical change rate to analyze the vertical deformation characteristics of the fault using the cross-fault leveling data during 1980-2017 locating on the Xianshuihe fault. The GPS inversion results indicate that in 1999-2007, the southeastern segment of the fault is tightly locked, the middle segment is less locked, and the northwestern segment is basically in creeping state. In 2013-2017, the southeastern segment of the fault is obviously weekly locked, in which only a patch between Daofu-Bamei is locked, and the northwestern segment is still mostly in creeping state, in which only a patch at southeastern Luhuo is slightly locked from surface to 10km depth. The cross-fault leveling data show that annual vertical change rate of the Zhuwo, Gelou, Xuxu and Goupu sites on the northwestern segment is larger, which means vertical movement is relatively active, and annual vertical change rate of the Longdengba, Laoqianning, and Zheduotang sites on the southeastern segment is small, which means the fault is locked, and the vertical movement changes little before and after the Wenchuan earthquake. Combining with the 3-dimensional movement and deformation, seismic activity and Coulomb stress on the Xianshuihe Fault, we consider the seismic risk of the southeastern segment is larger, and the Wenchuan earthquake reduced the far-field sinistral movement and the fault slip deficit rate, which may reduce the stress and strain accumulation rate and relieve the seismic risk of the southeastern segment.  相似文献   

中国火山温泉气体地球化学特征及其在火山监测中的应用     

魏费翔  许建东  上官志冠  潘波 《震灾防御技术》2018,13(4):938-949

中国火山温泉主要分布在吉林长白山、云南腾冲和黑龙江五大连池等火山区。这些火山虽然处于休眠状态，但大面积的温泉分布指示着岩浆房存在的可能性。本文总结了前人研究成果，分析了中国主要火山区温泉气体地球化学特征，并探讨了温泉气体在火山监测中的应用。长白山、腾冲和五大连池火山区温泉气体地球化学性质类似，都以CO₂为主要气体，含量在80%以上，最高可达99%以上，其它气体组分包括CH₄、N₂、O₂、SO₂、H₂S、He和H₂等。长白山火山温泉气体中氦同位素比值（3He/4He）最高，约为4—6R_A，CO₂中碳同位素比值（δ13C）为-7.9‰—-1.3‰，CH₄中碳同位素为-48.0‰—-28.7‰；腾冲火山温泉气体氦同位素比值为3—5.5R_A，CO₂中的碳同位素为-6.49‰—-2.07‰，CH₄中碳同位素为-23.5‰—-9.3‰；五大连池火山温泉气体氦同位素比值约为3R_A，CO₂中的碳同位素比值为-9.6‰—-3.1‰，CH₄中碳同位素为-47.2‰—-44.4‰。3个火山区的温泉气体均显示地幔来源的岩浆气体特征，并在上升运移过程中受地壳或古俯冲物质的影响。  相似文献   

河南省现代服务业集聚特征及影响因素分析     

孟琳琳  李江苏  李明月  宋莹莹 《世界地理研究》2020,29(6):1202-1212

现代服务业是伴随着科技发展而出现的一种新兴产业，对区域产业结构优化升级、促进经济发展等方面日趋重要。采用空间基尼系数、区位熵分析、EG指数和面板回归等方法，对2007—2017年河南省现代服务业集聚特征及影响因素进行分析，得出以下结论：①河南省现代服务业总体及其8个分行业集聚程度较高，其中科学研究和技术服务业集聚程度最高，教育最低；②河南省现代服务业总体及其8个分行业专业化水平较低，其中郑州市专业化水平最高，并在金融业，文化、体育和娱乐业2个行业表现出较强的集聚优势；③河南省现代服务业总体及其8个分行业空间集聚结构较差，发展还不成熟；④经济发展水平对河南省现代服务业发展影响最大，交通条件、资本支持、信息化水平和人力资本对现代服务业发展具有不同程度的促进作用，工业化水平、政府行为对其产生显著的负影响。  相似文献   

新疆S214公路台特玛湖干涸湖盆段风沙危害及防治     

蔡东旭  李生宇  王海峰  俞祥祥  王世杰  徐新文 《中国沙漠》2020,40(1):1-11

新疆S214（考干-米兰，考米线）公路位于库鲁克塔格沙漠东南缘，穿越台特玛湖干涸湖盆。由于该区气候干旱，风力强劲，沙源丰富，流动沙丘广布且快速移动，风沙危害对公路运输构成严重威胁。通过对风沙环境和风沙危害定位观测和土壤水盐特征系统调查，确定了风沙危害极为严重的公路区段，提出了合理的风沙防护措施及防沙体系结构。结果表明：该区具有明显的单风向风况，主要盛行ENE和NE风，偶有反向风沙活动，起沙风频率、输沙势、输沙率极高，属于高能-大比率风能环境；受土壤水分、盐分含量影响，地表紧实度差异较大，部分地段为极疏松的沙层，部分地段为紧实的盐壳；S214公路风沙危害防护区段为K4+900~K18+200，设计建造的阻-固-输相结合的机械-植物复合防沙体系，防沙效果明显，保障了道路安全运营。这一强风沙、高盐区公路防沙体系建设模式可为类似环境地区工程防沙提供借鉴。  相似文献   

全球粮食安全格局的时空演化     

蔡建明  马恩朴  林静  廖柳文  韩燕 《地理学报(英文版)》2020,30(2):179-196

Food security is the primary prerequisite for achieving other Millennium Development Goals(MDGs).Given that the MDG of“halving the proportion of hungers by 2015”was not realized as scheduled,it will be more pressing and challenging to reach the goal of zero hunger by 2030.So there is high urgency to find the pattern and mechanism of global food security from the perspective of spatio-temporal evolution.In this paper,based on the analysis of database by using a multi-index evaluation method and radar map area model,the global food security level for 172 countries from 2000 to 2014 were assessed;and then spatial autocorrelation analysis was conducted to depict the spatial patterns and changing characteristics of global food security;then,multi-nonlinear regression methods were employed to identify the factors affecting the food security patterns.The results show:1)The global food security pattern can be summarized as“high-high aggregation,low-low aggregation”.The most secure countries are mainly distributed in Western Europe,North America,Oceania and parts of East Asia.The least secure countries are mainly distributed in sub-Saharan Africa,South Asia and West Asia,and parts of Southeast Asia.2)Europe and sub-Saharan Africa are hot and cold spots of the global food security pattern respectively,while in non-aggregation areas,Haiti,North Korea,Tajikistan and Afghanistan have long-historical food insecurity problems.3)The pattern of global food security is generally stable,but the internal fluctuations in the extremely insecure groups were significant.The countries with the highest food insecurity are also the countries with the most fluctuated levels of food security.4)The annual average temperature,per capita GDP,proportion of people accessible to clean water,political stability and non-violence levels are the main factors influencing the global food security pattern.Research shows that the status of global food security has improved since the year 2000,yet there are still many challenges such as unstable global food security and acute regional food security issues.It will be difficult to understand these differences from a single factor,especially the annual average temperature and annual precipitation.The abnormal performance of the above factors indicates that appropriate natural conditions alone do not absolutely guarantee food security,while the levels of agricultural development,the purchasing power of residents,regional accessibility,as well as political and economic stability have more direct influence.  相似文献   

新疆准东煤田库兰喀孜干勘查区赋煤特征分析          下载免费PDF全文

孙增兵 《山东国土资源》2018,34(1)

该文以准东东部库兰喀孜干勘查区煤田钻探资料和勘探成果资料为基础,对区内煤炭资源分布特点、赋存特征和赋煤规律等方面进行了研究。区内主要含煤地层为中侏罗统西山窑组和下侏罗统八道湾组,含煤层23层,西山窑组19层,平均厚度45.55m,八道湾组3层,总厚度7.30m,其中2,9,13,15,17,21,23煤层为可采煤层,结合煤层厚度、岩性特征和测井结果,对区内煤层进行了对比。同时,从剖面纵向上总结了西山窑组和八道湾组煤层的垂向分布特征、含煤特征,总结了二者的平面展布特征,认为西山窑组煤层总厚度呈中间厚、四周薄的趋势,八道湾组煤层仅分布在井田中部和南部,厚度由南向北逐渐变薄。在此基础上,从沉积学特征、构造环境和沉积环境方面,对赋煤规律进行了浅析,认为煤层发育总体受沉积环境和基底沉降等地质条件的控制。  相似文献