大兴安岭北部漠河地区早奥陶世A型花岗岩锆石U- Pb年代学、地球化学及Hf同位素研究

大兴安岭北部漠河地区黑云母二长花岗岩中锆石自形程度较好,主要为长柱状,具有较为清晰的韵律环带结构,表明锆石岩浆成因。锆石LA-ICP-MS U-Pb年代学研究显示岩石形成时代为早奥陶世(481±5Ma)。岩石地球化学研究显示,岩石属于钙碱性、弱过铝质系列花岗岩,高硅(SiO_2=71.42%～72.57%)、富碱(ALK=8.11%～8.76%)、贫镁(MgO=0.52%～0.54%)。10000Ga/Al值为2.73～2.85,Zr+Nb+Ce+Y含量374×10~(-6)～495×10~(-6),岩浆形成温度801～897℃,判断岩石为A型花岗岩。岩石有中等的负Eu异常(δEu=0.24～0.35),Rb/Sr值为1.18～1.38、Ba/La值为8.7～12.4、Mg~#值为23.3～30.3,及低Ni(1.51×10~(-6)～5.59×10~(-6))、Cr(6.60×10~(-6)～13.4×10~(-6))、V(20.0×10~(-6)～21.6×10~(-6))含量。岩石的ε_(Hf)(t)值为-2.22～5.57,二阶段模式年龄(t_(DM2))变化于1021～1453Ma之间,主要源于中新元古代增生地壳。结合区域构造演化及构造判别,认为岩石形成于额尔古纳地块与西伯利亚板块拼合造山后的伸展背景。     

内蒙古早二叠纪火山熔岩痕量元素地球化学

本文报道了内蒙古东部早二叠纪火山岩的痕量元素地球化学特征,讨论了该区火山岩的源区特征,结果表明,内蒙古东部早二叠纪火山岩是不同性质组成的地幔不同程度部分熔融的产物。基性熔岩主要是具有亏损地幔性质的E－MORB高度部分熔融的产物,而中酸性火山岩的源区物质具有OIB特征。具有OIB型富集地幔特征的中酸性火山岩的源区可能是循环到地幔与海水发生强烈作用的古洋壳物质。这一结果表明,中晚古生代时期中朝板块与西伯利亚板块拼合后,俯冲到地幔中的古洋壳在早二叠纪以火山作用的方式返回到地壳环境中。     

Evaluation of CMIP5 Earth System Models in Reproducing Leaf Area Index and Vegetation Cover over the Tibetan Plateau

The abilities of 12 earth system models (ESMs) from the Coupled Model Intercomparison Project Phase5 (CMIP5) to reproduce satellite-derived vegetation biological variables over the Tibetan Plateau (TP) were examined. The results show that most of the models tend to overestimate the observed leaf area index (LAI) and vegetation carbon above the ground, with the possible reasons being overestimation of photosynthesis and precipitation. The model simulations show a consistent increasing trend with observed LAI over most of the TP during the reference period of 1986-2005, while they fail to reproduce the downward trend around the headstream of the Yellow River shown in the observation due to their coarse resolutions. Three of the models: CCSM4, CESM1-BGC, and NorESM1-ME, which share the same vegetation model, show some common strengths and weaknesses in their simulations according to our analysis. The model ensemble indicates a reasonable spatial distribution but overestimated land coverage, with a significant decreasing trend (-1.48% per decade) for tree coverage and a slight increasing trend (0.58% per decade) for bare ground during the period 1950-2005. No significant sign of variation is found for grass. To quantify the relative performance of the models in representing the observed mean state, seasonal cycle, and interannual variability, a model ranking method was performed with respect to simulated LAI. INMCM4, bcc-csm-1.1m, MPI-ESM-LR, IPSL CM5A-LR, HadGEM2-ES, and CCSM4 were ranked as the best six models in reproducing vegetation dynamics among the 12 models.     

Connections Between the South Asian Summer Monsoon and the Tropical Sea Surface Temperature in CMIP5

The South Asian summer monsoon (SASM) precipitation is analyzed based on reanalysis datasets and historical simulation results from 23 climate models of the Coupled Model Intercomparison Project phase ...     

基于多年卫星遥感的江苏省夏季城市热岛特征分析

利用2003—2020年的MODIS土地覆盖类型和地表温度等数据,从地表温度、气温和城市化的角度分析了江苏省夏季城市热岛强度和面积的时空分布和变化趋势。结果表明：近20 a快速的城市化导致了江苏省夏季热岛强度(0.07℃·a^-1)和热岛面积(529 km²·a^-1)整体均呈增加趋势;其中热岛强度前期受城区升温影响,呈明显增强(0.18℃·a^-1),后期受郊区升温影响,呈明显减弱(-0.14℃·a^-1);热岛面积变化主要由弱热岛面积(297 km²·a^-1)和较强热岛面积(192 km²·a^-1)的增长趋势主导,强热岛面积呈前期增长(133 km²·a^-1)和后期减少(185 km²·a^-1)的变化趋势;高温对整个城区的热岛效应影响有限,但对城市核心区的热岛效应影响明显,对应的强热岛面积增加和热岛强度增强。     

交互四元体系Li+, Mg2+//SO2-4, B4O2-7H2O 288 K

采用等温溶解平衡法研究了288K时Li+, Mg2+//SO2-4, B4O2-7- H2O四元体系的固液相平衡关系,测定了该四元体系在288K时平衡液相的溶解度和密度。依据实验测定的平衡溶解度数据及对应的平衡固相,绘制了该四元体系的平衡相图及密度组成图。研究结果表明：交互四元体系Li+, Mg2+//SO2-4, B4O2-7- H2O 288K时平衡相图中有2个共饱点,5条单变量曲线,4个结晶区对应的平衡固相分别为Li2B4O7·3H2O,Li2SO4·H2O,MgB4O7·9H2O和MgSO4·7H2O。     

基于组件MapObjects专题数据编辑模块的设计与实现

专题数据编辑模块是应用型GIS系统的必备功能。本文在分析MapObjects在专题数据编辑方面的特点的基础上,提出了基于MapObjects专题数据编辑模块的设计方法,并给出了VB MO在胜利采油厂管网信息系统(SCGIS)中专题数据编辑的具体实现方法。     

柴达木盆地北缘构造控藏特征与油气勘探方向

柴北缘油气成藏特征及油气分布受构造控制明显,但由于构造体系复杂,因此油气成藏主控因素及主要勘探方向不明。研究表明,由于柴北缘缺乏主要滑脱层,在晚新生代强烈挤压与走滑调整的控制下主要发育基底卷入式构造,形成上、下构造层变形相对一致的“破碎型”构造体系。柴北缘油气成藏条件、晚新生代两期成藏及其与构造形成时间的匹配关系决定了古近纪继承性古构造是油气运聚的有利部位,而喜山晚期构造调整使得油气分布复杂化,古构造发育、晚期改造强度与烃源岩演化、充注成藏的匹配关系决定了古近纪继承性古构造向凹陷延伸的侧翼部位是柴北缘油气勘探的有利部位,应坚持“破碎型”构造体系中相对稳定区的油气勘探。     

二连盆地中部古河谷砂岩型铀矿成矿特征及潜力分析

二连盆地早白垩世末期断拗转换的构造应力场背景,为赛汉组上段古河谷沉积的发育创造了有利的地质条件。赛汉组上段古河谷沉积是在下段辫状河三角洲沉积的基础上演化而成,由于湖泊沉积衰亡,形成了长流程的古河道砂体,为铀成矿提供了理想的赋矿空间。晚白垩世-古新世长时间的沉积间断,有利于氧化带的发育。因此,古河谷砂体和氧化带控制了盆地内的铀成矿。笔者通过以哈达图、赛汉高毕和巴彦乌拉铀矿床的对比分析,建立了二连盆地3种不同古河谷类型的铀成矿模式,并对其进行了潜力分析,指出找矿的方向。     

Oil and Gas Accumulation in the Foreland Basins, Central and Western China

<正>Foreland basin represents one of the most important hydrocarbon habitats in central and western China.To distinguish these foreland basins regionally,and according to the need of petroleum exploration and favorable exploration areas,the foreland basins in central and western China can be divided into three structural types:superimposed,retrogressive and reformative foreland basin(or thrust belt),each with distinctive petroleum system characteristics in their petroleum system components(such as the source rock,reservoir rock,caprock,time of oil and gas accumulation,the remolding of oil/gas reservoir after accumulation,and the favorable exploration area,etc.).The superimposed type foreland basins,as exemplified by the Kuqa Depression of the Tarim Basin, characterized by two stages of early and late foreland basin development,typically contain at least two hydrocarbon source beds,one deposited in the early foreland development and another in the later fault-trough lake stage.Hydrocarbon accumulations in this type of foreland basin often occur in multiple stages of the basin development,though most of the highly productive pools were formed during the late stage of hydrocarbon migration and entrapment(Himalayan period).This is in sharp contrast to the retrogressive foreland basins(only developing foreland basin during the Permian to Triassic) such as the western Sichuan Basin,where prolific hydrocarbon source rocks are associated with sediments deposited during the early stages of the foreland basin development.As a result, hydrocarbon accumulations in retrogressive foreland basins occur mainly in the early stage of basin evolution.The reformative foreland basins(only developing foreland basin during the Himalayan period) such as the northern Qaidam Basin,in contrast,contain organic-rich,lacustrine so urce rocks deposited only in fault-trough lake basins occurring prior to the reformative foreland development during the late Cenozoic,with hydrocarbon accumulations taking place relatively late(Himalayan period).Therefore,the ultimate hydrocarbon potentials in the three types of foreland basins are largely determined by the extent of spatial and temporal matching among the thrust belts,hydrocarbon source kitchens,and regional and local caprocks.