大洋玄武质岩石元素间的线性关系及其应用

批式熔融是大洋玄武质岩石形成的主要机制之一。本文建立了批式熔融作用中元素间的线性关系模型,并应用于北秦岭宽坪群变玄武质岩石化学分析资料的研究,对变异图解、相关矩阵、源区成分计算和估计等问题作了讨论。给出了一些具体应用的方法。     

安徽庐枞火山—构造洼地的形成,演化及成矿

庐枞火山-构造洼地是在构造和火山岩浆活动共同作用下产生的。从190Ma至105Ma其演化过程可分为五个阶段,共出现了9种金属和硫铁矿矿床类型,这些矿床在时-空分布上具有明显的规律性,在成因上具有一定的内在联系,构成了在长期沉降基底士的火山-构造洼地内、外与橄榄安粗岩系有关的成矿系列。本文提供了一个在剪切-挤压与剪切-拉张交替作用,而以剪切-拉张为主的构造背景下,在活动大陆边缘与板内过渡地带,一个火山-构造洼地及其成矿作用演化的四维模型。     

我国厄尔尼诺研究方法概述

该文在收集已有资料的基础上，对目前我国厄尔尼诺的研究方法作了概括和小结。在此基础上，提出：（1）资料处理方面，应在现有基础上，尽量运用目前先进的非线性方法，如人工神经网络、小波分析等来探讨尔尼诺发生的规律以及它的发生将对我国气候因素所造在的影响；（2）研究厄尔尼诺对某种气候要求（如降水）的影响时，应对某一季节（如夏季）转向为对某一月（如6月）甚至某些天（如暴雨阶段）上来，从而尽量减少因厄尔尼诺事件而造成的损失。     

Disequilibria between 210Po and 210Pb in surface waters of the southern South China Sea and their implications

Activities of the naturally occurring radionuclides, ²¹⁰Pb and ²¹⁰Po, were measured in both dissolved (<0.45 μm) and particulate (>0.45 μm) phases from surface waters of the southern South China Sea. The average activity of particulate ²¹⁰Pb, 0.23 Bq/m³ (n=23), accounted for about 12% of the total ²¹⁰Pb, which corresponds with values of open oceans. Particulate ²¹⁰Po, with an average activity of 0.43 Bq/m³, accounted for about 40% of the total ²¹⁰Po, which was much higher than those of open and eutrophic oceans. The residence times of total ²¹⁰Po and ²¹⁰Pb in surface waters estimated from an irreversible steady-state model were 0.82 a and 1.16 a, respectively. The consistently high fractionation factor calculated either by scavenging rate constants (5.42) or K_d values (6.69) suggested that a significant fractionation occurred between ²¹⁰Po and ²¹⁰Pb during their removal from solution to particles and that the two radionuclides had different biogeochemical cycling pathways in the oligotrophic South China Sea. Furthermore, our results indicated that there exist different fractionation mechanisms between ²¹⁰Po and ²¹⁰Pb in different marine environments: in eutrophic ocean, plankton detritus and fecal pellets are the main carrier of ²¹⁰Po and ²¹⁰Pb, by which ²¹⁰Po and ²¹⁰Pb have been scavenged and removed; while in oligotrophic ocean, microbes could become the main carrier of ²¹⁰Po and fractionate ²¹⁰Po and ²¹⁰Pb significantly as a result of scarce plankton detritus and fecal pellets. These results suggest the use of ²¹⁰Po to trace marine biogeochemical processes relating to microbial activities and the cycling of sulfur group elements (S, Se, Te and Po).     

长江河口最大浑浊带水沙输运机制分析

本文根据大量的实测资料，运用机理的分析方法，讨论了长江口最大浑浊带中各输沙项的作用。结果表明，平均流输沙、斯托克斯漂流效应、潮汐捕集以及垂向不流是净输沙的主要部分。     

我国南方桉树人工林区水体泛黑物质分子组成及形成机理

我国南方桉树人工林区水库在秋冬季频繁出现黑水现象。现有研究指出,桉树叶中单宁酸等物质与金属离子(如铁离子)反应产生的金属-有机质络合物是导致这一现象的主要原因。然而,目前对于桉树叶中能形成金属-有机质络合物的潜在有机质前体物认识仍然有限,基于分子组成层面的桉树人工林区水库水体泛黑形成机理也尚不清楚。为此,本研究利用傅立叶变换离子回旋共振质谱(FT-ICR MS)等手段,对桉树叶浸泡液与典型桉树林区水库(金窝水库和天雹水库)水体中可溶性有机物进行了分子组成的分析。研究结果显示,桉树叶浸泡液主要由以苯三酚、没食子酸为母体的多酚类化合物及其多聚衍生物构成,其中最典型的化合物是鞣花酸(C₁₄H₆O₈)。冬季水库水中鞣花酸强度远高于夏季,且表层水体高于底层水体,这表明秋冬季大量凋落的桉树叶释放出的这些芳香多酚类物质会显著促进水库黑水的形成。进一步的实验证明,鞣花酸、苯三酚和没食子酸都会与铁离子发生络合反应,生成黑色沉淀。这些结果均表明,桉树叶溶解出的芳香多酚类物质是导致水库变黑的核心因素。本研究基于分子组成层面提出了桉树人工林区水库水体泛黑形成机理,对于桉树人工林区的黑水治理和保障水库饮用水安全具有十分重要的意义。     

辽宁弓长岭含铁建造年代学研究

用热离子质谱计双带源蒸发—沉积测定单个锆石晶体年龄的方法对弓长岭含铁建造中黑云变粒岩、混合岩化浅粒岩和石英岩中的锆石作了测定,获得了2.60—2.54 Ga,3.36—2.62 Ga和3.53—3.08 Ga等年龄数据。结合已有的研究资料可以认为,黑云变粒岩的原岩来自2.7 Ga左右的中酸性火山物质,浅粒岩和石英岩的原岩来自3.0 Ga以上的花岗质地壳物质;含铁建造形成于陆壳基底之上,形成时间约2.7 Ga,并于2.5—2.7 Ga之间发生首次变质作用。     

四川昌北稀土矿床中的硅钛铈矿

1986年笔者在四川昌北稀土矿床中发现一种结晶完好的硅钛铈矿。矿物物理性质与我国白云鄂博产出者相似。矿物组分中富铌。晶体化学式为(Ce,La,Nd…Ca)_4Fe~(2+)(FeTiNb)_2Ti_2O_8[Si_2O_7]_2。经四圆单晶衍射和电子衍射测得晶胞参数相同,α=13.385(2),b=5.742(1),c=10.059(2),β=100.60(0.01)°,空间群C 2/m。对矿物晶体定向带轴进行了高分辨晶格象观测。     

湖南金刚石内部不均一性特征研究

将湖南金刚石加工成片，利用宝石显微镜，偏光镜，阴极发光（CL）仪和傅里叶红外光谱（FTIR）仪对其内部显微特征进行了研究，发现金刚石的颜色深浅不一，内外颜色差异明显，呈带状，斑状分布；金刚石由生长中心至边缘，氮含量也有较大变化，中心与边缘最大相差约50倍，氮的富集类型由中心向边缘表现出B中心所占的比例越来越小，金刚石的类型也相应从I型→II型或I－aAB型→-I-aA型等，这些不均一性特征，反映金刚石在生长过程中环境条件发生了变化，以及生长期后可能受到了改造。     

STUDY ON THE PHYSICAL PROCESS OF WINTER VALLEY FOG IN XISHUANGBANNA REGION

Xishuangbanna of Yunnan Province is a famous tropical foggy region. A field experiment wascarried out from November 23 to 30 of 1997 during which fogs occurred regularly every day. In thepaper the characteristics of macrostructure of fog are analyzed and the physical processes offormation and dissipation of fog are studied. The results show that the Xishuangbanna valley fogforms firstly in the lower atmosphere with two-layer structures and then develops suddenly in thevertical direction after reaching the ground. Furthermore, the vegetation effect on the formationand dissipation of fog is discussed specially.