南方亚热带季风区将乐县森林植被动态变化及其对气候变化的响应     

左冰洁  孙玉军 《地球信息科学学报》2019,21(6):958-968

在全球气候变化背景下,植被动态变化以及植被对气候变化的响应方式已经成为生态学和地理学领域的热点。本文对比分析了南方亚热带季风区将乐县不同类型森林植被对不同时间尺度的干旱响应的差别。基于2000-2017年MODIS-EVI数据及气象站点数据,用最大值合成法、趋势分析法以及相关分析法,分析了森林植被及气象因子的动态变化特征,并对比不同森林植被对气候变化响应的差别。研究表明：① 2000-2017年,研究区植被覆盖度、EVI和降水均显著增加,区域内湿度增加,森林长势渐趋良好;② EVI在生长季初期和末期与同期的降水、温度均显著正相关（P<0.1）,初期森林受降水因子的影响更大,末期受温度因子的影响大;③ 1-3月和周年的气候变化对森林的生长至关重要,长时间尺度的湿度增加对森林生长具有显著的促进作用,SPEI的时间尺度越长与EVI的相关性也越大;④ 针阔混交林与同期温度、降水的相关系数最高,并且与不同时间尺度的SPEI相关性均比较高,属于气候敏感型林型,在生产经营中要谨慎预防气候变化对该林型带来的伤害;⑤ 森林覆盖度变化与降水和SPEI_24的相关性极显著,长时间尺度的降水变化是影响森林植被覆盖率变化的重要因素之一。  相似文献   

新疆博格达白杨沟的枕状熔岩：岩石地球化学和Sr-Nd-Pb同位素特征   总被引：1，自引：0，他引：1       下载免费PDF全文

熊发挥  杨经绥贾 毅徐向珍  陈松永李天福任玉峰  左国朝 《中国地质》2011,38(4):838-854

新疆博格达造山带北段东侧白杨沟地区分布有大面积的晚石炭世至早二叠世的火山岩,岩石主要由亚碱性玄武岩和安山岩组成,其中分布有大量保存极好的枕状熔岩。枕状熔岩主要为基性熔岩,SiO2含量50.17%～54.66%,Al2O3为13.10%～16.44%,MgO为4.62%～7.89%,TiO2为1.23%～2.79%,CaO为7.06%～13.07%,Na2O为2.76%～4.99%,K2O为0.07%～0.82%。基性熔岩的大离子亲石元素(LILE)一组为富集如Rb和Ba,另一组相对亏损;高场强元素(HFSE)如Nb和Ta在N-MORB标准化图解上都具有明显的负异常。熔岩的稀土元素在球粒陨石标准化配分图解中表现为总体平坦,轻稀土元素(LREE)轻微富集的右倾曲线,δEu为0.89～1.12。从Sr-Nd-Pb同位素组成来看,εNd(t)为+2.8～+3.1,143Nd/144Nd(i)为0.512407～0.512422,εSr(t)为-14.0～-17.5、87Sr/86Sr(i)为0.70293～0.70317、206Pb/204Pb(i)为17.622～17.835、207Pb/204Pb(i)为15.3...  相似文献   

Geochemistry of Ore-bearing Lamprophyre from the Cu-Ni Deposit in Dhi Samir, Yemen     

ZUO Liyan  an  PEI Rongfu  SHUAI Kaiye  YANG Fengqi  ZHU Riwei  ZHANG Liemeng 《《地质学报》英文版》2011,85(1):200-210

Magmatic Cu-Ni sulfide deposits are generally associated with mafic-ultramafic rocks and it has not been reported that lamprophyre is one of the surrounding rocks of Cu-Ni sulfide deposits. The Dhi Samir deposit in Yemen, however, is a rare example of Cu-Ni deposits which are hosted in lamprophyre dikes. In this paper, comprehensive research is made on petrology, petrochemistry and isotope geochemistry for Cu-Ni-bearing rocks in the Dhi Samir area and the results show that dark rocks related to Cu-Ni orebodies are sodium-weak potassium and belong to calc-alkaline series lamprophyre, especially camptonite, characterized by enriched alkali, iron and titanium. In these rocks large-ion-lithophile elements are obviously concentrated, while high field strength elements slightly depleted, showing clear negative anomalies of Ta and Nb, and weak deficiency of Ti. The SREE is very high (225.67-290.05 ppm) and the REE partition curves are flat and right-inclined, featuring a LREE-enriched pattern with low negative Eu anomalies. Study of magmatic source areas indicates that the rocks have low (87Sr/86Sr) and high εNd(t), and the magmas were probably derived from the enriched mantle I (EM-I) end-member. Based on the LA-ICPMS on zircon U-Pb isotope dating, the lamprophyre in the Dhi Samir mining area has an age of 602±2.6 Ma, indicating that the rock was formed in the late Proterozoic and in an intraplate setting due to magmatism of an extensional environment in the post-Pan-Africa orogeny.  相似文献   

Data Analysis of Chang’E-1 Gamma-Ray Spectrometer and Global Distribution of U, K, and Th Elemental Abundances     

ZOU Yongliao  ZHANG Liyan  LIU Jianzhong  MU Lingli  REN Xin  ZHANG Guangliang  CHANG Jin  YAN Jun  ZHANG Nan  ZHANG Hongbo  Lü Chang  LIU Jianjun  ZUO Wei  SU Yan  WEN Weibin  BIAN Wei  WANG Min  XU Chun  LI Chunlai  OUYANG Ziyuan 《《地质学报》英文版》2011,85(6):1299-1309

Gamma-ray spectrometer (GRS) is one of the main payloads on the Chang’E-1 (CE-1) lunar probe, mainly aimed to detect the elemental abundances and distributions on the lunar surface. At 03:58 on 28 November 2007, it performed the first observation of the lunar gamma rays. As of 24 October 2008, 2105?h of effective gamma rays spectra had been acquired by CE-1 GRS, which covers the whole surface of the moon. This paper mainly describes the data processing procedures and methods of deriving the elemental abundances by using the CE-1 GRS time series corrected spectra: first, to bin data into pixels for mapping; then, to perform a background deduction of the cumulative spectra and obtain a peak area of the elements; and finally, to use the elemental abundances inversion model to produce the elemental abundances. Based on these processing methods, the global abundance maps of U, K, and Th at a 5°×5° equal-area pixel are acquired by CE-1 GRS data. The paper gives a preliminary analysis of the uncertainties of the elemental abundances  相似文献   

甘肃省北山地区罗雅楚山—大红山一带区域构造格局、褶皱样式及断裂系     

左国朝  刘义科  李绍雄 《甘肃地质》2011,(1):6-15

甘肃北山地区罗雅楚山—大红山一带,赋存青白口纪沉积变质铁矿,由元古宙以来,本区经历了多期次构造变动,形成了现今相互叠置的复杂地质体,其加里东运动及海西运动奠定了本区总体褶皱样式。印支运动发育了逆冲断裂系。最为特色的是燕山运动导致本区大规模由南向北推覆的推覆构造,喜山运动为相对稳定的升降运动。  相似文献   

赣北大湖塘矿田特大型钨矿床成矿条件及成矿模式探讨     

左全狮  程雯娟 《矿产与地质》2015,(2)

文章收集了大湖塘矿田成矿信息资料,从成矿物源、成矿动力作用、成矿通道与赋存空间、成矿岩体化学特征、特别事件与成矿偏在性等方面,探讨了大湖塘矿田特大型矿床的形成条件和成矿模式。认为燕山早期多次岩浆侵入这一特别事件造就了大湖塘矿田巨大的成矿空间、丰富的成矿流体、多次聚集成矿;讨论了矿田围岩具有形成特大型矿床的成矿偏在性,得出特大型矿床主要是在燕山早期大规模岩浆活动和成矿大爆发这一特别事件与矿田特殊围岩的耦合机制下形成的。认为原大湖塘矿区具有形成特大型矿床的条件,有可能成为大湖塘矿田内又一个特大型钨多金属矿床。  相似文献   

Using of Key Stratum Theory to Study the Structural Development of Roof Aquifer     

CHEN Li  ZHANG Fawang  YAO Hongchao  HAN Zhantao  QIAN Long  CHEN Liang  JIANG Chengchao 《《地质学报》英文版》2015,89(6):2091-2091

<正>During the underground mining of coal resources,overlying rocks on the roof of excavated tunnels will be destroyed due to ground pressure,and as a result,part of them will break and fall into the tunnels.How to determine the distribution of fractured areas and fissures presents a major problem for preserving the overlying aquifer.In most cases,the distribution of fissures induced  相似文献   

坦桑尼亚盖塔(Geita)绿岩带型金矿矿床地质特征          下载免费PDF全文

龚鹏辉  刘晓阳  王杰  许康康  左立波  孙凯  刘宇 《地质找矿论丛》2015,30(S1):93-97

盖塔(Geita)金矿是坦桑尼亚重要的绿岩带型金矿之一。文章阐述了矿床地质背景、矿床地质特征,以及矿床同位素年代特征,并对矿床成矿模式进行了对比。在此基础上认为盖塔金矿以块状黄铁矿和浸染状黄铁矿的矿化为主,成矿时代约为2644~2680Ma,属于太古宙热液型金矿床,具有明显的"层控"特征,后生成矿模式可能是盖特金矿的矿床成因。  相似文献   

博茨瓦纳赛莱比-皮奎铜镍硫化物矿床研究进展          下载免费PDF全文

任军平  许康康  刘晓阳  王杰  左立波  孙凯  何胜飞  贺福清 《地质找矿论丛》2015,30(S1):129-136

文章对博茨瓦纳铜镍硫化物矿床的研究成果进行了总结,概括了赛莱比-皮奎铜镍硫化物矿床的区域地质背景、岩石地层划分,较系统地分析了矿床的地质特征和矿床成因;认为铜镍硫化物矿床的成矿物质来源多样,并且矿床形成后经历了强烈的褶皱和剪切作用。  相似文献   

贵州茶树生长季热量资源的时空分布特征研究     

田月  赵孟  李勇  易俊莲  左晋 《贵州气象》2015,39(2):1-5

该研究根据贵州省1961—2010年茶树生育期内积温的气象观测资料,分析了贵州春、夏、秋茶季内热量资源的时空变化特征。结果表明:研究区茶树生育期热量资源最充足的是夏茶季,其次是秋茶季,最少的则是春茶季;春茶季、夏茶季及秋茶季热量资源的空间分布特征相似,都是由西到东逐渐增加;而且3个茶季生育期的热量资源从1961—2010年期间都呈增加趋势;春茶季、夏茶季、秋茶季热量资源呈现减少趋势的站点占研究区域总站点数的比例分别为9.9%、46%、12.3%。春茶季、夏茶季、秋茶季热量资源的地区间差异均呈现缩小的趋势。  相似文献