贵州夜郎湖表层水体地球化学昼夜变化及其影响因素     

王家录  任娟  王勇  李维杰  娄昭  陈佳 《热带地理》2020,40(2):335-345

为探究岩溶水库水文地球化学行为过程,对贵州普定夜郎湖表层水体进行了为期3 d的高分辨率昼夜监测。结果表明：1）多变的天气和水文条件叠加导致水体离子指标昼夜变化不显著,规律性较差。而水温、DO、pH值、SpC、SIc、pCO₂等常规理化指标受水温变化和生物作用表现出明显的昼夜波动。2）利用亨利常数和主成分分析,得到温度变化、生物作用、人类活动、水库的蓄水与放水对夜郎湖水库水文地球化学特征变化的贡献率分别为21.66%、17.28%、14.08%和10.22%,说明作用于水库水文地球化学行为的因子具有多元性。3）δ ¹⁸O表现出与DO一致的波动趋势,即白天上升,晚上下降,反映在短时间尺度上,氢氧稳定同位素变化受控于生物过程（主要是呼吸作用过程）;而对比水库水体和大气降水的d-excess（d值）发现,水库水体的d值（8.21‰）显著偏低于当地大气降水的d值（9.64‰）,说明在长时间尺度上,主要受蒸发效应引起的不平衡分馏影响。  相似文献   

Overview of In - Situ Biodegradation and Enhancement     

DONG Jun  Anthony Adzomani  Zhao Yongsheng 《世界地质(英文版)》2002,5(1)

Microbial degradation technologies have been developed to restore ground water quality in aquifers polluted by organic contaminants effectively in recent years. However, in course of the degradation, the formation of biofilms in ground water remediation technology can be detrimental to the effectiveness of a ground water remediation project. Several alternatives are available to a remedial design engineer, such as Permeable Reactive Barriers (PRBs) and in -situ bioremediation, Hydrogen Releasing Compounds (HRCs) barrier, Oxygen Releasing Compounds (ORCs) barrier etc. which are efficient and cost- effective technologies. Excessive biomass formation renders a barrier ineffective in degrading the contaminants, Efforts are made to develop kinetics models which accurately determine bio - fouling and bio - filn formation and to control excessive biomass formation.  相似文献   

The first and second order moments of the polarization profiles of hydrogen lines     

R. HCasini  E. Landi Degl'Innocenti 《Solar physics》1996,164(1-2):91-96

The main properties of the first- and second-order moments of polarized hydrogen lines, forming in the presence of stationary electric and magnetic fields, are reviewed. The analytical results presented here apply directly to the case of optically-thin emission lines in the LTE regime. Some applications of such results to electric- and magnetic-field diagnostics in (solar) plasmas are then briefly considered.On leave from the Dipartimento di Astronomia e Scienza dello Spazio, Università di Firenze, Largo E. Fermi 5, I-50125 Firenze, Italy  相似文献   

Reef exploration in the East Sengkang Basin,Sulawesi, Indonesia     

A.M. Grainge  K.G. Davies 《Marine and Petroleum Geology》1985,2(2):142-155

Reconnaissance seismic shot in 1971/72 showed a number of well defined seismic anomalies within the East Sengkang Basin which were interpreted as buried reefs. Subsequent fieldwork revealed that Upper Miocene reefs outcropped along the southern margin of the basin. A drilling programme in 1975 and 1976 proved the presence of shallow, gas-bearing, Upper Miocene reefs in the northern part of the basin. Seismic acquisition and drilling during 1981 confirmed the economic significance of these discoveries, with four separate accumulations containing about 750 × 10⁹ cubic feet of dry gas in place at an average depth of 700 m. Kampung Baru is the largest field and contains over half the total, both reservoir quality and gas deliverability are excellent. Deposition in the East Sengkang Basin probably started during the Early Miocene. A sequence of Lower Miocene mudstones and limestones unconformably overlies acoustic basement which consists of Eocene volcanics. During the tectonically active Middle Miocene, deposition was interrupted by two periods of deformation and erosion. Carbonate deposition became established in the Late Miocene with widespread development of platform limestones throughout the East Sengkang Basin. Thick pinnacle reef complexes developed in the areas where reef growth could keep pace with the relative rise in sea level. Most reef growth ceased at the end of the Miocene and subsequent renewed clastic sedimentation covered the irregular limestone surface. Late Pliocene regression culminated in the Holocene with erosion. The Walanae fault zone, part of a major regional sinistral strike-slip system, separates the East and West Sengkang Basins. Both normal and reverse faulting are inferred from seismic data and post Late Pliocene reverse faulting is seen in outcrop.  相似文献   

SOHM-4与MHM-2010氢原子频标的特点比较     

梁双有  任燕  尹学玉 《时间频率学报》2005,28(1):61-67

基于对已投入国家授时中心守时运转的SOHM-4型与MHM-2010型氢原子频标的长期关注,对这两种氢原子频标的性能作了较详细的比较和分析。讨论了它们共同的优点、各自的特长和不足之处,还给出了稳定度的测试结果。  相似文献   

Ultrahigh pressure macro diamonds from Copeton (New South Wales, Australia), based on Raman spectroscopy of inclusions   总被引：1，自引：0，他引：1  

L.M. Barron  B.J. Barron  T.P. Mernagh  W.D. Birch 《Ore Geology Reviews》2008,34(1-2):76

Mining of Cenozoic alluvial deposits at Copeton and Bingara (Eastern Australia) has produced two million macrodiamonds (0.25 ct median size). Raman spectroscopy is used to identify included minerals within uncut Copeton diamonds, with sealed chamber remnant pressures of 31.7 to 35.6 kbar for coesite, 13.6 and 22.7 kbar for clinopyroxene, and 7.6 kbar for grossular garnet. Assuming elastic behaviour, these values generate inclusion entrapment PT loci which intersect, restricting diamond formation conditions: from 250 °C, 43 kbar to 800 °C, 52 kbar. Larger than error (± 100 °C and ± 4 kbar), this range shows a systematic variation in inclusion composition with diamond zoning and N properties. Published research shows 1) Copeton and Bingara diamonds are unique, and 2) modern alluvium in the Bingara district carries mantle-formed garnet, captured by post-tectonic alkali basalt from an extensive diamondiferous ultrahigh pressure (UHP) terrane that stalled at depth because it is dominated by mafic eclogite. The combined Raman and geological results indicate two sets of subduction UHP diamond formation conditions/protolith are required, firstly cooler oceanic slab and secondly including higher temperature continental crust. The Copeton and Bingara stones are UHP macrodiamonds, and Carboniferous ⁴⁰Ar/³⁹Ar age dates on clinopyroxene inclusions should be interpreted as ages of crystallisation, representing the termination of subduction. The characteristic features of ruptured inclusions and etched percussion marks on Copeton and Bingara diamond indicate volcanic delivery to the earth's surface. Alluvial deposits elsewhere in Eastern Australia may carry similar diamond along with diamond of different origin.  相似文献   

EPR investigation of the methyl radical,the hydrogen atom and carbon oxide radicals in Maxixe-type beryl     

Lars Olov Andersson 《Physics and Chemistry of Minerals》2008,35(9):505-520

The EPR spectra of Maxixe-type beryl contain a large number of overlapping signals. The angular dependence of the 1:3:3:1 signal typical for the CH₃ radical shows that this radical is located at the center of the channel cavity with its symmetry axis parallel to the crystal c-axis and is rotating around this axis. Its EPR spectrum is axially symmetric with g _// = 2.00263, g _⊥ = 2.00249 and A_// = 2.288 mT, A_⊥ = 2.256 mT. These anisotropies have the opposite signs of those found for surface-adsorbed methyl radicals. Hydrogen atoms are located at position 2a at the center of the beryl cavity and the EPR parameters of the narrow doublet signal are A ₀ = 1,407 MHz and g = 2.00230. Another doublet signal, which is broader and has axial symmetry with g _// = 2.00265, g _⊥ = 2.00625 and A_// = 0.895 mT, A_⊥ = 0.885 mT, could come from a HCO₃ radical. One narrow and easily saturated signal with g _// = 2.00227 and g _⊥ = 2.00386 is interpreted to arise from a carbon monoxide radical in the beryl channel, oriented with its axis parallel to the crystal c-axis. Additional weak doublet lines, which have similar g values as the carbon monoxide radical, are created by nearby hydrogens. A powder spectrum with g _// = 2.0017 and g _⊥ = 2.0004 appears upon UV irradiation of the single crystal and is easily saturated. This spectrum is interpreted to arise from a carbon dioxide radical, which rotates around its symmetry axis.  相似文献   

长江中下游地区二叠纪碳酸盐斜坡沉积及其成矿意义   总被引：13，自引：1，他引：12  

李双应  孟庆任  万秋  孔为伦  何刚 《岩石学报》2008,24(8)

长江中下游地区二叠系发育,主要由碳酸盐岩、硅质岩和碎屑岩组成.其二叠系不仅是华南地区最重要的烃源岩,而且也是长江中下游铜等多金属成矿带的重要赋矿层位之一,因此,进一步确定其沉积相以及古地理意义重大.发育在长江中下游地区的二叠系以往多被认为主要属于浅水碳酸盐台地沉积,其次是较深水的陆棚沉积或者裂陷槽沉积.但进一步研究发现,二叠系的碳酸盐斜坡沉积相发育,它主要由砾屑石灰岩、泥晶粉屑灰岩、硅质岩和泥晶灰岩组成,斜坡主要发育于中二叠世的栖霞期和茅口期,其次是吴家坪期和长兴期.碳酸盐斜坡主要沿安徽铜陵-东至-宿松-线以及湖北大冶-江西瑞昌一线分布,其成因大致受江南断裂和长江断裂控制.同沉积断裂不仅控制着碳酸盐斜坡的发育和展布,同时也构筑了深水盆地、斜坡和浅水台地沉积体系,构成油气生、储、盖单元的组合,为二叠系成为华南地区最重要的烃源岩提供了成因解释.控制斜坡发育的断裂既可以是含矿热水溶液、海底热泉和火山的通道,同时斜坡带也可以成为金属硫化物矿床的富集场所,因此,它对长江中下游铜多金属成矿带的层控和喷流成因提供了可选择的解释.长江中下游地区中、晚二叠世断裂发育,显示盆地的伸展特征,符合古特提斯洋东扩构造背景.  相似文献   

近190ka BP以来菲律宾海黑潮源区的碳酸盐旋回及其控制因素   总被引：2，自引：0，他引：2  

赵京涛  常凤鸣  李铁刚  南青云  李青 《岩石学报》2008,24(6):1401-1410

对取自西菲律宾海黑潮源区的Ph05-5和WF3岩芯进行了CaCO3和钙质超微化石研究.在利用氧同位素曲线对比和AMS14C数据进行地层划分的基础上,结合钙质超微化石的碳酸盐溶解指数和初级生产力指标,分析了晚第四纪黑潮源区碳酸盐旋回特征及其控制因素.约190ka BP以来CaCO3含量整体上都表现为冰期高、间冰期低的"太平洋型"旋回特征,但菲律宾以东海区在末次冰期(MIS 4到MIS 2期)内部又显示出间冰段含量高、冰段含量低的"大西洋型"旋回特征.碳酸盐旋回的控制因素在黑潮源区内部也有明显的差异,菲律宾以东海区以碳酸盐溶解作用为主,初级生产力起次要作用;而台湾东南部海区的主要因素则是初级生产力变化引起的钙质生物输入量的波动.菲律宾以东海区末次冰期内部表现出的"大西洋型"旋回特征则是溶解作用和初级生产力共同影响的结果.  相似文献   

黄河三角洲沿岸及邻近海区细粒沉积物中的碳酸盐   总被引：4，自引：0，他引：4  

何良彪 《海洋科学》1991,15(3):41-45

本文用X-射线衍射法直接计算了来自黄河三角洲沿岸及邻近海区80个沉积样的细粒组分(<2μm)中的碳酸盐含量。计算结果与全样的容量法分析结果基本一致。研究结果表明,本区细粒沉积物中碳酸盐含量变化受沉积物来源、海区水动力作用、海底地貌特征和碳酸盐的地球化学行为等因素所影响。  相似文献