重庆金佛山羊口洞滴水δD和δ18O变化特征及其环境意义

为探究重庆金佛山羊口洞滴水δD、δ18O化特征及其环境意义,于2011年10月—2013年8月,在重庆市南川区金佛山逐月采集大气降水样品及羊口洞6个滴水监测点的滴水样品进行氢氧稳定同位素测定。通过比较降水和滴水δD、δ18O的分布特征、季节变化及其与降水量和温度的相关性发现：（1）6个滴水点δD、δ18O较均匀地分布在当地降水线附近,表明从降水到形成滴水的过程受蒸发作用影响不大,滴水δD、δ18O现了当地大气降水δD、δ18O均水平。（2）受洞穴上覆岩土层的调蓄作用影响,羊口洞各滴水点δD和δ18O变化范围（—46.77~—62.09‰,—7.05~—9.96‰）远小于洞外大气降水（5.17~—115.63‰和—1.44~—16.10‰）,且较降水存在明显滞后性。但滴水δD、δ18O体上也表现出与降水相同的夏季偏轻、冬季偏重的趋势,主要受降水水汽源地季节性差异影响。而各个监测点滴水δD和δ18O节变化差异较大,可能受滴水点上覆岩层裂隙管道发育、覆盖层厚度、岩溶水滞留时间、形成滴水前的运移路径、滴水点的高度和滴率、滴水点距离洞穴出入口的距离等多种原因影响。（3）降水δ18O现出＂降水量效应＂和＂负温度效应＂,羊口洞滴水δ18O降水量总体上也呈负相关关系,而与温度（水温、洞温）的关系则呈现多样化：1#、2#、5#、6#监测点滴水δ18O温度不相关,3#点为正相关,4#点为负相关,这与各监测点滴水δ18O节变化差异较大有关。（4）总体而言,羊口洞滴水δD和δ18O季节变化不够明显,利用羊口洞石笋进行季节分辨率的古气候重建可能性较低,但滴水δD和δ18O承了当地大气降水信息,其石笋δ18O用于重建年际~十年际及更长时间尺度的古气候变化。     

西藏拉屋铜多金属矿床的成矿流体特征与成矿机制研究

西藏拉屋铜多金属矿床产于冈底斯构造岩浆成矿带的申扎—旁多铜-银-铅-锌-金成矿亚带内。分别对干矽卡岩阶段(Ⅰ)的石榴石、早期硫化物阶段(Ⅲ)的石英和晚期硫化物阶段(Ⅳ)的方解石中的流体包裹体进行岩相学观察和显微测温研究,研究表明成矿各阶段热液矿物中的流体包裹体主要为气液水两相包裹体,其次为纯液相水包裹体,偶见气液两相甲烷包裹体,石英中也有大量的含NaCl子矿物多相包裹体,其均一温度变化于95～476℃之间,盐度介于1.57%～37.33%,密度变化于0.68～1.23 g/cm3,总体属中-高温、中-高盐度、中等密度的体系;据此计算的成矿压力范围为24.63～133.61 MPa,成矿深度介于2.46～9.64 km,表明该矿床形成于中深成矿环境。不同成矿阶段流体包裹体研究数据表明,该矿床的成矿作用是一个温度、盐度和压力总体显著降低(减小)、密度略渐增大的过程。氢、氧同位素研究表明,成矿流体在主成矿阶段主要为初始混合岩浆水,随着成矿作用进行,大气降水大量加入,到晚期阶段成矿流体逐渐演化成大气降水。成矿流体在Ⅲ阶段(主成矿阶段)发生了沸腾作用,导致成矿元素沉淀形成矿体。因此认为沸腾作用可能是该矿床金属沉淀的主要机制。     

Chitosan removes toxic heavy metal ions from cigarette mainstream smoke

This study investigated the removal of heavy metal ions from cigarette mainstream smoke using chitosan. Chitosan of various deacetylation degrees and molecular weights were manually added to cigarette filters in different dosages. The mainstream smoke particulate matter was collected by a Cambridge filter pad, digested by a microwave digestor, and then analyzed for contents of heavy metal ions, including As(III/V), Pb(II), Cd(II), Cr(III/VI) and Ni(II), by graphite furnace atomic absorption spectrometry (GFAAS). The results showed that chitosan had a removal effect on Pb(II), Cd(II), Cr(III/VI) and Ni(II). Of these, the percent removal of Ni(II) was elevated with an increasing dosage of chitosan. Chitosan of a high deace tylation degree exhibited good binding performance toward Cd(II), Cr(III/VI) and Ni(II), though with poor efficiency for Pb(II). Except As(III/V), all the tested metal ions showed similar tendencies in the growing contents with an increasing chitosan molecular weight. Nonetheless, the percent removal of Cr(III/VI) peaked with a chitosan molecular weight of 200 kDa, followed by a dramatic decrease with an increasing chitosan molecular weight. Generally, chitosan had different removal effects on four out of five tested metal ions, and the percent removal of Cd(II), Pb(II), Cr(III/VI) and Ni(II) was approximately 55%, 45%, 50%, and 16%, respectively. In a word, chitosan used in cigarette filter can remove toxic heavy metal ions in the mainstream smoke, improve cigarette safety, and reduce the harm to smokers.     

特长公路隧道集中排烟方式研究

纵向通风排烟是我国长大公路隧道发生火灾时通风的主要形式,目前开始应用一种新型的特长公路隧道纵向通风集中排烟方式。本文借助CFD三维数值模拟技术,对两种排烟方式在火灾时的烟气控制效果进行了对比分析,研究了顶部设排烟道时,不同排烟开口大小和排烟口间距对隧道火灾时排烟效果的影响。研究表明：顶部设排烟道排烟较纵向通风排烟有较好的烟气控制效果,排烟口的设置间距和开口大小将影响隧道火灾时的排烟特性。     

甘肃酒西盆地青西凹陷下白垩统下沟组湖相喷流岩物质组分与结构构造*

甘肃酒西盆地青西凹陷下白垩统下沟组广泛发育的暗色纹层状细粒岩,以其富含铁白云石、钠长石、重晶石、方沸石、黄铁矿和有机质,局部含有微量萤石、透闪石、石盐和呈碎屑状、浸染状产出的微量闪锌矿、黄铜矿、方铅矿等矿物组分吸引着众多沉积地质学家和石油地质学家的高度关注。在以往的研究中,大多数研究者认为此类细粒岩的成因与火山活动有关,将其确定为火山物质蚀变作用的产物。通过地质背景、物质组分、岩石结构构造、包裹体和地球化学特征的研究,提出此类细粒岩属于新型的湖相“白烟型”喷流岩,可识别出6种热水矿物组合、3种主要结构类型和4种常见的原生沉积构造。6种热水矿物组合包括: Ⅰ钠长石—铁白云石(或铁白云石—钠长石)组合,Ⅱ重晶石—钠长石—铁白云石组合,Ⅲ石英—重晶石—钠长石—铁白云石组合,Ⅳ石英—方沸石—钠长石—铁白云石组合,Ⅴ地开石—铁白云石组合,Ⅵ单一铁白云石组合。3种主要结构类型包括: ①泥晶—微晶结构,②内碎屑结构,③石盐假晶结构。4种常见的原生沉积构造包括: ⅰ纹层状和条带状构造,ⅱ网脉状充填构造,ⅲ旋涡状喷管结构,ⅳ同生变形层理结构。在物质组分和岩石结构分析的基础上,划分出网脉状充填型、水爆型、盆地沉积型和区域扩散型4种喷流岩产状类型,建立了下沟组湖相喷流岩分带性沉积模式,探讨了喷流岩研究意义。     

Origin and Distribution of Grain Dolostone Reservoirs in the Cambrian Longwangmiao Formation, Sichuan Basin, China

Dolostones in the Cambrian Longwangmiao Formation have become one of the most significant gas exploration domains in China. Over a trillion cubic meters of gas reservoirs have been discovered in the Gaoshiti-Moxi area; however, the origins and distribution of the dolostone reservoirs are not well understood. This work discussed the geology and geochemistry of the dolostone reservoirs in the Longwangmiao Formation to determine their origin and distribution. Two understandings are acquired: firstly, a carbonate ramp provided excellent conditions for grain beach deposition, while the presence of a hypersaline lake was favorable for the contemporaneous dolomitization of grain beach deposits. Petrographic and geochemical evidence further confirm that the Longwangmiao dolostone was formed during the contemporaneous stage. Secondly, the reservoir characteristics indicate that the grain beach sediments provide material basis for the development of the Longwangmiao dolostone reservoirs. Reservoir dissolution simulation experiments show that the porosity of the reservoirs was formed by dissolution during contemporaneous and burial stages. The dissolution pores formed during the contemporaneous stage were controlled by sequence interfaces. The large scale dissolution vugs formed during the burial stage subsequently spread along the pre-existing porosity and fracture zones. This study therefore identified that the development of grain dolostone reservoirs in a shallow water ramp under arid climatic conditions generally met the following conditions: (1) reefal beach deposits lay a foundation for reservoir development; (2) superficial conditions are an important determining factor for reservoir porosity; and (3) burial conditions provide environment for porosity preservation and modification.     

巴丹吉林沙漠东南部湖泊和地下水的氢氧同位素特征

通过对巴丹吉林沙漠湖泊和地下水氢氧同位素分析,讨论了沙漠湖水和地下水的补给关系,并结合地下水可溶性固体总量的特征,进一步探讨了巴丹吉林沙漠的蒸发特性。根据氢氧同位素的分析结果,本研究区的蒸发趋势线方程为:δD=4.1δ18O-30.02‰（n=37,R2=0.94）较低的斜率显示了巴丹吉林沙漠强烈的蒸发环境特征。巴丹吉林沙漠东南部湖泊和地下水具有相似的蒸发趋势,推测两者之间存在补给关系。根据沙漠腹地地下水氧同位素值富集程度高于东南部地下水氧同位素值的特点,得出前者蒸发较后者强烈。进而对比其他干旱条件下盐湖的蒸发,结果显示巴丹吉林沙漠湖水存在过度蒸发效应。     

成都地区大气降水稳定同位素组成反应的气候特征

分析了1986-1998年成都地区大气降水的稳定同位素组成。夏季降水的δD和δ^18O值比冬季降水轻,反映了季风气候的降水特点。成都地区的大气降水线方程是：δD=1．42＋7．530δ^18O,与全球和中国降水线方程相比,表明了成都地区的蒸发程度稍大于降雨,说明成都地区大气降水的不平衡蒸发程度弱,反映了海洋性气候特征。成都地区大气降水δ^18O与降雨量、温度和水汽压之间都是负相关关系。但是降雨量对大气降水δ^18O的影响最大。     

环境矿物材料在土壤、水体、大气污染治理中的利用

本文在简要阐明了环境矿物材料对污染物的净化机理与净化功能的基础上,明确了环境矿物材料的应用领域,重点展望了在土壤重金属污染防治、地表水和地下水水质改善及燃煤固硫除尘等三类状态污染控制与环境保护领域中应用的前景。认为经济、简便、有效地用于污染治理与环境修复的无机界矿物学方法类似于有机界生物学方法,均是自然界地球系统中天然自净化作用的反映。     

火灾烟颗粒分形模型和球形模型光散射的比较研究

对烟颗粒的光散射进行模拟计算是研究火灾烟颗粒光散射特性的重要手段,目前对于火灾烟颗粒光散射的数值计算多采用球形或椭球模型.实际上,火灾烟颗粒的形貌与球形和椭球均存在着显著差异.扫描电子显微镜图像表明,烟颗粒具有近似分形的结构.本文利用离散偶极近似方法计算了随机取向的火灾烟颗粒分形凝团以及同体积的球形颗粒的光散射Muller矩阵,并对两者的归一化Muller矩阵元素随散射角的分布进行了比较.研究表明:火灾烟颗粒分形模型和球形模型的归一化矩阵元素F₁₁(θ)/F_{11相似文献}