扬子板块西北缘下泥盆统平驿铺组双壳类遗迹化石

四川北部广元地区下泥盆统平驿铺组产出丰富的双壳类遗迹化石,但尚未开展过系统的遗迹学工作,也未进行过行为学与古生态学分析。文中针对四川广元马家剖面平驿铺组中部地层开展沉积学和系统遗迹学研究,在陆棚至近滨带下部沉积中共识别出3个属种的双壳类遗迹化石,包括Lockeia siliquaria,Protovirgularia rugosa,Ptychoplasma vagans,以及其他无脊椎动物门类遗迹化石Cruziana problematica,Dimorphichnus isp.,Lophoctenium isp.等。对双壳类遗迹化石的出现方式、形态以及保存特征的分析表明,平驿铺组中部曾出现过2种类型的双壳类,分属具分叉足(原鳃目)和楔状足的类群。原鳃目分布于过渡带和陆棚区,营沉积物摄食生活;受高能事件或沉积物掩埋影响,它们由停息状态变为“逃逸”状态的行为产生了Pro.rugosa。具楔状足的双壳类依生态类型可分为2类：在过渡带与陆棚区,漫游的、营沉积物摄食的类型产生了Pty.vagans;而在近滨下部,滤食性双壳类居群则在不同期次高能事件的间隙对沉积物进行大规模殖居,产生了L.sil...     

Seismic Characterization of Naturally Fractured Reservoirs with Monoclinic Symmetry Induced by Horizontal and Tilted Fractures from Amplitude Variation with Offset and Azimuth

Surveys in Geophysics - Geological and geophysical data acquired from naturally fractured hydrocarbon reservoirs usually exhibit the presence of multiple sets of fractures. Two different...     

The response law of far-field seismic ground motion of the Wenchuan earthquake and its damaging mechanism in the Loess Plateau

A series of housing collapses and other serious damage was caused by the 2008 Wenchuan M_S 8.0 earthquake in the seismic intensity Ⅵ areas of the Loess Plateau, which is hundreds of kilometers away from the epicenter, and which showed a remarkable seismic intensity anomaly. The seismic disasters are closely related to the seismic response characteristics of the site, therefore, the systematic study of the far-field seismic response law of the Wenchuan earthquake in the Loess Plateau is of great significance to prevent the far-field disaster of great earthquake. In this paper, the seismic acceleration records of several bedrock stations and loess stations from the seismogenic fault of the Wenchuan earthquake to the Loess Plateau were collected, and the attenuation law of ground motion along the propagation path and the characteristics of seismic response on the loess site are studied, and the mechanism of amplification effect of ground motion is analyzed based on the dynamic feature parameters of the loess site obtained through the HVSR method. Taking a typical loess site of thick deposit as the prototype, a series of shaking table tests of dynamic response of loess site models with different thicknesses were carried out. Amplification effect, spectral characteristics of acceleration in model sites were analyzed under the action of a far-field seismic wave of the Wenchuan earthquake. The results show that seismic attenuation on the propagation path along the NE strike of the seismogenic fault to the Loess Plateau is slower than that in other directions, and the predominant period range of ground motion on bedrock site of the Loess Plateau presents broadband characteristics. Because the natural periods of loess sites with thick deposits are within the predominant period range of bedrock input wave, loess sites appear significant amplification effect of ground motion, the horizontal acceleration of ground motion exceeds 0.1 ?g, the seismic intensity reaches 7°. The thicker the loess deposit is, the more significant the change of spectral characteristics of ground motion on loess sites, and the narrower the predominant period range of ground motion becomes, and the closer it is to the natural period of loess sites. Therefore, for some old houses on thick loess sites, the poor seismic performance and strong seismic response eventually led to their collapses and damages because their natural periods are very close to the predominant period of ground motion of the Wenchuan earthquake on thick loess sites; For these damaged high-rise buildings, the resonance effect might be the main reason for their damages because their natural periods are included in the predominant period range of ground motion of the Wenchuan earthquake on thick loess sites.These research results would provide a basis for seismic disasters prediction and evaluation and seismic design of construction engineering in the Loess Plateau.     

内蒙古查干础鲁金矿地质特征及其金的产出特征

查干础鲁金矿矿体赋存在侵位于阿木山组的浅成超浅成次火山岩(次石英粗安岩)中,是受构造控制的蚀变岩型金矿床。通过对次石英粗安岩的岩石学特征、矿物学及地球化学特征进行分析,显示出次石英粗安岩为贫钙型铝过饱和系列,是金矿床的主要赋矿岩石,其次为细粒闪长玢岩。有用组分主要为Au,其次为Ag。金主要以自然金形式存在,主要与次石英粗安岩中的石英脉关系密切,或是存在于假象黄铁矿及褐铁矿中,虽然微粒金产出数量最多,但从面积比上看,则以粗粒金、巨粒金为主,赋存状态以晶隙金为主,包体金及裂隙金较少。自然金粒形态主要为片状、弯曲片状、不规则片状。     

新疆准噶尔盆地西北缘上泥盆统两个新地层单元

新疆准噶尔沙尔布尔提山及其附近地区是中国准噶尔—兴安地层区泥盆系及下石炭统发育的主要代表地区之一,历来受到地质学界的关注,研究工作也不断深入。本文主要涉及洪古勒楞组的下伏及上覆地层。将20世纪70年代区测队建立的洪古勒楞组及"和布克河组"底部的一套砾岩—砂岩—粉砂岩地层单独建立为哈尔段(新名)。哈尔段下部以大套砾岩为特征,可与下伏地层原朱鲁木特组的粉砂岩至砂岩地层明显区别。两者接触面起伏不平,可能代表了一定的沉积间断。哈尔段地层总体颜色为灰绿色、紫红色、深灰色等,仅产植物化石,未见海相化石,目前仅能依靠其中的斜方薄皮木确定其时代为晚泥盆世,与原朱鲁木特组时代一致,此外在岩相上也均属于陆相。本文将黑山头组下部称为那木段,以含铁锈色介壳层的深灰色致密钙质硅质粉砂岩以及暗色或灰色、灰绿色硅质泥岩、粉砂岩与(细)砂岩等为特征,与黑山头组中部(属石炭系)大套灰黑色的粉砂岩-泥岩的岩性有明显区别,也与下伏风化呈(褐)黄色的洪古勒楞组查斯段明显区别。该段含菊石Cymaclymenia spp.、Mimimitoceras sp.等以及三叶虫Omegops,表明其仍属于泥盆系;此外,该段新出现Syringothyris-Spirifer腕足类动物群,因而不同于查斯段的弓石燕类腕足动物群。     

Some Opinions on Rock-Weathering-Related Carbon Sinks from the IPCC Fifth Assessment Report

Many recent researches show that rock-weathering-related carbon sink, especially carbonate-weathering-related carbon sink, actively takes part in the modern global carbon cycle, which might greatly contribute to balancing global carbon budget. Some new opinions on flux, time scale and effect of rock-weathering-related carbon sink were released in IPCC fifth Assessment Report (AR5). The flux of global rock-weathering-related carbon sink is about 0.4 Pg C/a in AR5 report, which accounts for about 1/2~1/3 of unbalanced global carbon budget. New time scale of global rock-weathering-related carbon sink was released. Time scale of silicate-weathering-related carbon sink is 10⁴~ 10⁶ year, while carbonate-weathering-related carbon sink (karst processes) is 10³~10⁴ year. A highlight is that rock-weathering-related carbon sink is listed as one of four carbon dioxide removal methods in AR5 report, whose time scale is 10²~ 10³ year. Although AR5 report released these new opinions, it is still thought that the rate of global rock-weathering-related carbon sink is currently too small to offset the rate at which fossil fuel CO₂ is being emitted. According to many researches in the field of rock weathering science in the past decades, this review discussed the shortage in carbon flux, time scale and effect of rock-weathering-related carbon sink in AR5 report. Many recent researches indicated that the carbon sink originated from carbonate rock weathering was a fast and sensitive geochemical process, which showed multiple time scales (diel, seasonal, annual or storm event). A new model based on H₂O carbonate-CO₂-aquatic phototroph interaction was established, which coupled geological, land surface water, and submerged phototroph carbon cycle process. The global carbon sink from carbonate rock weathering in new model is 0.477 Pg C/a,which accounts for about 39%~59% of unbalanced global carbon budget. Some key scientific issues on rate, stability, controlling mechanisms and scaling of rock-weathering-related carbon sink should be vitally concerned in the future, which could greatly contribute to balancing the global carbon budget.     

甘蒙北山后红泉地区海相玄武岩地球化学、年代学特征及成因

甘蒙北山地区发育的海相二叠系地层是中亚造山带南缘最年轻的海相沉积地层之一,为进一步探讨二叠纪古亚洲洋的关闭及后期的碰撞造山作用的时间节点,选取甘蒙北山后红泉地区二叠系海相火山岩-碎屑岩地层的5条代表性剖面进行了岩性-岩相及分布特征研究,并对海相地层中的玄武岩进行了岩相学、元素地球化学以及全岩Sr-Nd同位素等研究,同时选择剖面典型岩石进行了LA-ICP-MS锆石U-Pb定年.获得流纹英安岩与含砂亮泥晶生屑灰岩年龄分别为273±1.7 Ma和275.8±1.4 Ma,结合已发表年龄数据及古生物资料,明确了火山岩的喷发时代介于早二叠世亚丁斯克期-中二叠世沃德期,应厘定为双堡塘组;地球化学研究表明,后红泉地区玄武岩SiO₂含量介于47.48%~54.56%,主要为玄武岩和玄武安山岩,属钠质拉斑玄武岩;稀土总量（ΣREE）较高,为74.90×10-6~173.61×10-6,LREE/HREE为2.32~6.55,表现出轻稀土相对重稀土轻微富集,（La/Yb）_N=1.30~6.20,在球粒陨石标准化分布曲线整体上呈现LREE轻度富集、配分曲线平缓的特征,相对富集La、Ce、Nd、Zr、Hf等元素,不同程度地亏损Ta、Nb、P、Ti等元素,δEu=0.83~1.20,无明显的Eu异常;（87Sr/86Sr）_i为0.702 024~0.706 432,ε_Nd（t）值介于1.99~6.54（除了-0.59和-0.83）.因此,后红泉地区玄武岩岩浆是由接近原始地幔成分的石榴石二辉橄榄岩低程度熔融形成,其演化成岩过程中并未经地壳的强烈混染,而在岩浆源区发生了强烈的混染作用,推测软流圈地幔受到了陆源沉积岩、大陆地壳或蚀变大洋地壳改造,岩石圈拆沉作用可能是其产生的重要机制;说明古亚洲洋在早期已闭合,至早-中二叠世进一步拉张裂解形成了裂谷盆地.      

An integrated assessment of INDCs under Shared Socioeconomic Pathways: an implementation of C<Superscript>3</Superscript>IAM

A series of global actions have been made to address climate change. As a recent developed climate policy, Intended Nationally Determined Contributions (INDC) have renewed attention to the importance of exploring temperature rise levels lower than 2 °C, in particular a long-term limit of 1.5 °C, compared to the preindustrial level. Nonetheless, achieving the 2 °C target under the current INDCs depends on dynamic socioeconomic development pathways. Therefore, this study conducts an integrated assessment of INDCs by taking into account different Shared Socioeconomic Pathways (SSPs). To that end, the CEEP-BIT research community develops the China’s Climate Change Integrated Assessment Model (C³IAM) to assess the climate change under SSPs in the context of with and without INDCs. Three SSPs, including “a green growth strategy” (SSP1), “a more middle-of-the-road development pattern” (SSP2) and “further fragmentation between regions” (SSP3) form the focus of this study. Results show that after considering INDCs, mitigation costs become very low and they have no evident positive changes in three SSPs. In 2100, a temperature rise would occur in SSP1-3, which is 3.20, 3.48 and 3.59 °C, respectively. There are long-term difficulties to keep warming well below 2 °C and pursue efforts toward 1.5 °C target even under INDCs. A drastic reduction in greenhouse gas emissions is needed in order to mitigate potentially catastrophic climate change impacts. This work contributes on realizing the hard link between the earth and socioeconomic systems, as well as extending the economic models by coupling the global CGE model with the economic optimum growth model. In C³IAM, China’s energy consumption and emissions pattern are investigated and refined. This study can provide policy makers and the public a better understanding about pathways through which different scenarios could unfold toward 2100, highlights the real mitigation and adaption challenges faced by climate change and can lead to formulating effective policies.     

两次非典型厄尔尼诺期间热带太平洋主流系和赤道行星波研究

两次非典型厄尔尼诺事件发生期间,Walker环流中的西太平洋部分显着减弱,Hadley环流中的东太平洋部分显着增强.西太平洋距平西风应力增强向东伸展;东太平洋距平北风应力增强向南伸展.西太平洋暖池的能量可以两种方式向东传播:赤道Kelvin波温跃层模态和流速模态.温跃层模态向东输送的总能量大于流速模态向东输送的总能量.1982～1983年厄尔尼诺事件中,赤道Kelvin波温跃层模态起主要作用,赤道潜流减弱;1986～1987年厄尔尼诺事件中,赤道Kelvin波流速模态起主要作用,赤道潜流增强.厄尔尼诺事件期间,赤道潜流消失、反向现象是一种局地性海洋响应,这种现象不伴随赤道Kelvin波向东传播.     

热红外遥感用于陡河水库生态环境研究

由航空成象光谱仪热红外图象、红外辐射温度等遥感数据，和环境调查非遥感数据相结合，从水禀不体热污染、悬浮物污染、库区内水草生长对水体散热影响方面的生态环境因素分析，讨论作为唐山市饮用水水源地的陡河水库，其水质如何控制在《地面水环境质量》Ⅲ类水质标准。确保２０００年后唐山市居民有高质量的饮用水。