新疆“帕米尔式”铁矿床成因与成矿背景分析     

张德贤  曹汇  曾敏  许明珠  李广旭  星显宏 《岩石学报》2016,32(12):3847-3864

帕米尔式"铁矿床是新疆西昆仑地区重要的磁铁矿床类型之一,其矿床地质特征、形成时代明显有别于典型的BIFs类型磁铁矿床。本文以塔什库尔干地区翁吉勒磁铁矿床和孜勒依磁铁矿床作为研究对象,通过研究其赋矿围岩和岩体的岩石地球化学特征、矿石矿相学特征、磁铁矿微量元素地球化学特征和原位Pb-Pb同位素特征,探讨了"帕米尔式"磁铁矿床的矿床成因和成矿背景。岩石地球化学研究表明翁吉勒黑云母二长花岗岩具有高SiO_2、Al_2O_3、K_2O和Na_2O。低MgO、CaO和TiO_2,而Na_2O/K_2O值变化范围很小。铝饱和指数为(1.44~1.51),显示其具有为弱过铝质岩石的特征,稀土总量富集,具有强的负Eu异常。在微量元素蛛网图上显示其富集大离子亲石元素(LILE),如K、Rb、Sr、Ba及轻稀土元素(LREE),亏损Nb、Ta,P、Ti等高场强元素。而黑云母石英片岩稀土含量亦较富集,具有中等强度的负Eu异常。低的Rb/Sr比,明显的Th、Zr、Hf、Nb、Ta,P、Ti负异常,明显的Ba正异常,显示岩石具有古大陆边缘环境的富铝沉积岩特征。翁吉勒黑云母二长花岗岩和布伦阔勒岩群黑云母石英片岩地球化学性质非常相似,表明翁吉勒黑云母二长花岗岩的形成与布伦阔勒岩群黑云母石英片岩的重熔有关。锆石LA ICP-MS定年结果表明翁吉勒黑云母二长花岗岩形成于15.0±0.3Ma和15.4±0.2Ma。磁铁矿LA ICP-MS微量元素地球化学特征表明翁吉勒铁矿床中的磁矿床中主要Si、Mn、Zn、Sn、Hf和Pb相对较高,其中Mn和Ga变化范围较大,而孜勒依铁矿床中的磁铁矿具有相对较高的亲石元素,如Mg、Al、Ti、V、Co、Ni、Ga和Sc等,其Mn和Zn含量较低且变化范围较大,其它元素变化范围均相对较窄。二者相比,翁吉勒铁矿床中的磁铁矿中微量元素变化范围相对较大,而孜勒依铁矿床中的磁铁矿变化范围较小。两个矿床的磁铁矿的原位Pb-Pb同位素存在明显的不同,两类岩石全岩Pb同位素与两个矿床中磁铁矿Pb-Pb同位素研究表明翁吉勒铁矿床中磁铁矿可能与黑云母二长花岗岩有关,为热液成因。综上所述,在塔什库尔干地区不仅存在与沉积作用有关的铁矿床,还可能存在一部分与年轻岩浆岩有关的热液型磁铁矿床。  相似文献   

长江三峡地区的夷平面在宜昌地区白垩纪—第四纪沉积物中的反映          下载免费PDF全文

王金元  向芳  张瑶  王誉婉 《沉积与特提斯地质》2016,36(1):77-84

通过对湖北宜昌地区白垩纪—第四纪沉积演化的研究,发现存在3个明显的沉积旋回,每个旋回由下部颗粒粗大的砾石层和上部颗粒较细小的粉砂-泥质层组成。3个沉积旋回对应了宜昌以西三峡地区3期构造演化旋回,同时反映了三峡地区3期夷平面的存在。结合前人研究结果、古生物化石和对第四系善溪窑组的测年数据,认为3期夷平面形成时代分别为:鄂西期夷平面形成于白垩纪晚期—古近纪的始新世,山原期夷平面形成于上新世—早更新世初,云梦期夷平面形成于早更新世末—中更新世早期。  相似文献   

Modeling photosynthesis and the growth of marine phytoplankton     

V. I. Zvalinsky  P. Ya. Tishchenko 《Oceanology》2016,56(4):527-539

The paper analyzes the most popular models of photosynthesis and growth of marine phytoplankton in the literature and demonstrates their limitations. A new approach to modeling is proposed and used to obtain new models of marine phytoplankton photosynthesis and growth. An important feature of the proposed models is their ability to describe coupled multisubstrate cyclical interactions typical of biochemical and physiological processes. As a first approximation, the mathematical models are represented by equations of nonrectangular hyperbolas. The models describe the stoichiometry of extraction of elements from the medium, whatever the degree of their limitation, an important feature in describing biogeochemical cycles of elements. This stoichiometry is governed by measurable internal parameters of an organism (substrate parameters) and can be a key cause of stoichiometric formation of elements in the ambient medium, described, for example, by the Redfield ratio. The substrate constants are fundamental characteristics of the models, which form “automatically” in the construction of model equations in arbitrary units.  相似文献   

Modeling of oil spreading in a problem of radar multiangle diagnostics of Sea surface pollutions     

A. Ya. Matveev  A. A. Kubryakov  A. G. Boev  D. M. Bychkov  V. K. Ivanov  S. V. Stanichny  V. N. Tsymbal 《Izvestiya Atmospheric and Oceanic Physics》2016,52(9):940-950

The possibilities of a multiangle method of radar diagnostics to determine thickness of an oil film on a sea surface by comparing the radar data with the quantitative modeling results obtained using the model of oil spreading dynamics are analyzed. The experimental results of the remote sensing of the Caspian Sea water area near the Neftyanye Kamni oil field by the Envisat-1 synthetic aperture radar (SAR) and the new Floating Objects Tracking System (FOTS) model of oil spreading are used for the analysis. The model allows to calculate the dynamics and change in the mass and size of an oil slick basing only on the available data of satellite measurements and atmospheric reanalysis.The model takes into account the main processes that influence the slick formation (gravity spreading, advective transport, dispersion, emulsification, turbulent mixing, and evaporation). This model is used to calculate the thickness evolution and dynamics of the displacement of oil slicks in the period between two consecutive radar images of this region (0.5–4 days) and to estimate the volumes of oil spilled in the field. The good consistence of the height of the oil film calculated using radar measurements and the modeling results confirms the method’s reliability.  相似文献   

Influence of a spatial structure of precipitates on polarization characteristics of the outgoing microwave radiation of the atmosphere     

Ya. A. Ilyushin  B. G. Kutuza 《Izvestiya Atmospheric and Oceanic Physics》2016,52(1):74-81

Issues of the formation and recording of the spatial and angular distributions of thermal radio radiation of rainfall in the microwave range are discussed. The thermal radio-frequency radiative transfer in a threedimensional rain cell is simulated numerically with a different rainfall rate, taking into account the nonspherical shape of falling raindrops and their size distribution. The role of the three-dimensional inhomogeneity of rainfall fields in the formation of a field of their inherent thermal radio radiation in the microwave range is revealed.  相似文献   

白令海夏季浮游植物的群落结构与时空变化     

王雨  项鹏  叶又茵  林更铭  杨清良  林和山  林茂 《海洋学报(英文版)》2016,35(4):99-107

通过1999年和2010年夏季同期7月在白令海(169°E~166°W,50°N~67°N)获取的94份浮游植物样品分析,获得了近十年的始末两个时间节点的浮游植物群落结构与时空变化,探讨了浮游植物群落动态及其与环境因素的关联。研究结果显示,共鉴定浮游植物(>10μm)5门58属153种,分为3个生态类群。硅藻是浮游植物的主体,种类多丰度高,占总种类数目的66.7%,占总丰度的95.2%。鉴于样品属性和空间范围的不同,物种组成有细微差别,丰度有较大差异且空间分布明显不同,高丰度区受控于上层营养盐供给和表层环流系统。优势种从北方温带大洋性硅藻演变为广温广盐性与冷水性硅藻,1999年以西氏新细齿状藻为第一优势种,柔弱伪菱形藻次之;2010年以丹麦细柱藻为第一优势种,冷水性的诺登海链藻次之并在陆架和陆坡占优。浮游植物群落结构较为稳定,由深水群落和浅水群落组成。深水群落分布于太平洋西北部和白令海盆,种类组成以温带大洋性的西氏新细齿状藻、长海毛藻、大西洋角毛藻和广布性的菱形海线藻、扁面角毛藻、笔尖根管藻为主,丰度低,种间丰度分配均匀,优势种多元化,物种多样性高;浅水群落分布于白令海陆坡和陆架,主要由冷水性的诺登海链藻、叉尖角毛藻、聚生角毛藻和广布性的丹麦细柱藻、旋链角毛藻组成,丰度高,种间丰度分配不均匀,优势种突出,物种多样性低。白令海夏季浮游植物种类组成及丰度变化直接受控于表层环流、营养盐、春季冰缘线等环境因素。  相似文献   

Generation of the low-frequency branch of acoustic emission in affected rocks     

I. Ya. Chebotareva  I. A. Volodin  V. V. Dryagin 《Doklady Earth Sciences》2016,468(1):511-513

As follows from data analysis of physical modeling, the reaction of acoustic background oscillations to an external impact is well-defined under triaxial loading of a dry sandstone core in the low-frequency range (1–100 Hz). This phenomenon is explained by the generation of a low-frequency constituent of acoustic emission. A high correlation of oscillation dynamics (Klimontovich S entropy) is observed at frequencies of tens of hertz and tens of kilohertz in the absence of such a correlation in the intermediate frequency range; a synchronous increase in the oscillation level is also observed at low and high frequencies.  相似文献   

The proto-terrestrial mechanism of the appearance of water and early genesis of the global ocean     

S. Ya. Sergin 《Doklady Earth Sciences》2016,469(2):892-894

We consider chemical reactions for the appearance of water during the formation of the planet from cosmic gas and dust material to explain the early geological existence of the Earth’s hydrosphere. This process is fully supported by the resources of the initial substances and thermal energy. Thus, the concept of V.I. Vernadsly about the geological eternity of the World Ocean and ancient age of the oceanic lithosphere is supported. The identical high location of the ancient and modern continental platforms under the conditions of continual isostatical equilibrium in the asthenosphere–lithosphere–hydrosphere gives grounds to conclude that the ocean water depth is stable. Taking this into account, we can consider that the geological evolution of the Earth began in the conditions of the existence of the World Ocean when the mass of the hydrosphere only slightly exceeded the modern one.  相似文献   

Discussion on “Dynamics model to simulate water and salt balance of Bosten Lake in Xinjiang,China” (Environmental Earth Sciences 2015; 74(3): 2499–2510)     

Nuo Wang  Ya Li  Weijie Zhao  Nan-qi Song 《Environmental Earth Sciences》2016,75(11):971

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深海细菌太平洋火色杆菌中α-淀粉酶基因amy608的克隆表达及其酶学性质研究          下载免费PDF全文

商谢谢  蔡亚萍  金敏  曾润颖 《应用海洋学学报》2016,35(1):130-137

从来自深海沉积物的太平洋火色杆菌(Flammeovirga pacifica)的基因组中发现了一个全长为1 875 bp的α-淀粉酶基因amy608.该基因在数据库中找不到具有同源性的序列,而所编码的Amy608蛋白与已注册蛋白的氨基酸序列相似性最高仅为56%,但具有α-淀粉酶水解活性所必需的保守基序DXEXD.进化树分析表明其属于糖苷水解酶13(GH13)家族第二亚家族.构建了p ColdΙ-amy608表达载体,在大肠杆菌中进行重组Amy608蛋白的异源表达,并采用镍离子亲和层析柱对重组蛋白进行了纯化.酶学性质分析表明,重组酶Amy608的最适作用温度为40℃,在40℃保温4 d后,仍保留70%以上的酶活,显示出良好的中温热稳定性;最适p H值为7.0,p H值范围在6~9时仍保留60%以上的酶活力,表明该酶具有较宽的p H值作用范围.Ca2+、Na+、K+对α-淀粉酶Amy608有激活作用,尤其是Ca2+可使酶活显著提高40%.薄层色谱分析结果显示该酶水解可溶性淀粉的最终产物以葡萄糖为主,表明该酶是一个糖化型淀粉水解内切酶.这些结果表明Amy608为GH13家族第二亚家族中一个新型的α-淀粉酶.  相似文献