湖南骑田岭芙蓉矿田成岩成矿时代的厘定及其地质意义

通过对湖南骑田岭岩体芙蓉超单元南溪单元中粒斑状角闪石黑云母二长花岗岩、芙蓉矿田白腊水矿区的10号矿脉中蚀变花岗岩型锡矿石、19号矿脉中矽卡岩型矿石矿物、42号含矿花岗斑岩体和ZK801钻孔(80~90m)的细粒花岗岩的Rb-Sr、Sm-Nd和锆石SHRIMP U-Pb同位素年代学研究,分别获得南溪单元弱蚀变花岗岩全岩Rb-Sr等时线年龄为146±10Ma(95%可信度)和岩体锆石SHRIMP U-Pb年龄为155±6Ma(95%可信度),蚀变矿化花岗岩锆石SHRIMP U-Pb年龄为156±5Ma(95%可信度),10号蚀变花岗岩型矿脉矿石的Rb-Sr等时线年龄为137±5Ma(95%可信度),19号矽卡岩型矿脉的矿石—矿物Sm-Nd等时线年龄为133±15Ma(95%可信度);42号含矿花岗斑岩体锆石SHRIMP U-Pb年龄为146±5Ma(95%可信度);ZK801钻孔中细粒花岗岩全岩的Rb-Sr等时线年龄为140±7Ma(95%可信度)。上述精确的年代学研究结果表明,芙蓉超单元花岗岩侵位时间为燕山早期,而不是印支期。由此推测骑田岭芙蓉超单元花岗岩形成于早—中侏罗世,它的构造环境可能为地壳处于强烈剪切挤压晚期,而区内花岗斑岩和细粒花岗岩岩浆活动可能发生在140~145Ma之间,其构造环境可能为地壳由挤压剪切向拉张伸展转化的时期形成的;白腊水矿区不同类型矿床年代学研究结果(133~141Ma)清楚地表明,其成矿作用的时间与区内花岗斑岩和细粒花岗岩的岩浆活动时间有明显的耦合关系。据此推断,骑田岭芙蓉锡矿是在晚侏罗世,地壳由挤压剪切向拉张伸展转化的时期形成的。而与芙蓉花岗岩主体侵入岩浆活动无直接成生关系。     

面向地理信息大数据的时空事件关系可视化分析框架

不同类型的地理信息大数据蕴含了丰富的时空关系，反映个体或者群体时空事件之间的变化模式，在资源、环境、交通等领域的智慧应用中起到关键性作用。然而，地理信息大数据拥有的多尺度和多语义特性，在挖掘地理信息大数据的时空关系时会存在许多困难。如何有效地构建多尺度多语义时空关系，并直观地表达这些时空关系是一个重大挑战。本文设计了一种时空事件关系可视化分析框架，通过定义事件间时空关系的描述，设计了一种多视图协同的可视化分析方法，结合时空关系的可视化协同交互，实现地理信息大数据时空事件可视分析。基于时空轨迹数据，通过试验说明该方法可以探寻时空事件及背景间的时空关系，实现时空事件的交互可视分析。     

二道沟金矿床中黄铁矿的标型特征

本文从黄铁矿形态、成分、物理性质和硫同位素方面研究了二道沟金矿床中黄铁矿的标型特征,得出二道沟金矿黄铁矿的标型特征是:晶形以五角十二面体、立方体或其聚形品为主,高S/Fe值,高As、Bi、AuAg,高As/Sb值,高Cu、Pb、Zn,低Hg、Co、Ni,Co/Ni值大于1。黄铁矿导电类型为空穴型、混合型和电子型,以混台型为主;δ~(34)‰直绝大多数为-2—+3。研究表明,黄铁矿标型可直接作为寻找和评价金矿的矿物学标志以及确定矿床成因的指示标志。     

海洋生态系统动力学浅说

讨论了海洋生态系统动力学的研究目的，任务和特点。阐述了它的基本理论问题，此外，协同性，可预报性，突变性以及稳定性是人们关切的问题也是海洋生态系统动力学理论研究的重要内容。并对海洋生态系统动力学模型及模拟的基本概念和了描述，进而说明建模时要注意抽象与简化。最后就我国开展海洋生态系统动力学研究提出了一点看法。     

澜沧—耿马地震发震构造初步研究

本文根据澜沧—耿马地震形变带、极震区及余震序列分布特征,分析了7.6和7.2级地震的发震构造,认为北北西向旱母坝断层是7.2级地震的发震构造,7.6级地震的发震构造不是一条单一的断层,北西向木嘎断裂和北北西向澜沧—勐海断裂均有明显破裂表现,这一特点与震区复杂的地质构造背景有密切联系。     

论湖南省泥盆系层控矿床的分类

本文就不同学者所提出的层控矿床分类方案进行了综合评述,论述了作者们近年来研究湖南省泥盆系层控矿床提出的一种新的分类方案,将其分为沉积—改造型(简称改造型)、后成渗滤热液型(简称渗滤型)和岩浆热液叠加型(简称叠加型)三大类;然后根据矿种及成矿元素组合分成若干类,再根据矿体形态及矿体与赋矿地层的整合关系分成若干小类。并就湖南省泥盆系内产出的矿床作了具体划分,总结了各类矿床的特点与区分标志。改造型矿床主要是黄铁矿床,矿质来自泥盆系,成矿受沉积相和同沉积断裂控制,渗滤型矿床主要为铅锌、锑、金矿床,矿质来自下伏岩层,成矿受成岩后长期活动断裂控制,叠加型矿床主要为钨、铅锌、磁黄铁矿等矿床,矿质主要来自燕山期岩体,成矿受燕山期断裂和岩浆作用控制。该分类对指导层控矿床的找矿勘探具有重要意义。     

Production of γ-linolenic acid and stearidonic acid by <Emphasis Type="Italic">Synechococcus</Emphasis> sp. PCC7002 containing cyanobacterial fatty acid desaturase genes

Genetic modification is useful for improving the nutritional qualities of cyanobacteria. To increase the total unsaturated fatty acid content, along with the ratio of ω-3/ω-6 fatty acids, genetic engineering can be used to modify fatty acid metabolism. Synechococcus sp. PCC7002, a fast-growing cyanobacterium, does not contain a Δ6 desaturase gene and is therefore unable to synthesize γ-linolenic acid (GLA) and stearidonic acid (SDA), which are important in human health. In this work, we constructed recombinant vectors Syd6D, Syd15D and Syd6Dd15D to express the Δ15 desaturase and Δ6 desaturase genes from Synechocystis PCC6803 in Synechococcus sp. PCC7002, with the aim of expressing polyunsaturated fatty acids. Overexpression of the Δ15 desaturase gene in Synechococcus resulted in 5.4 times greater accumulation of α-linolenic acid compared with the wild-type while Δ6 desaturase gene expression produced both GLA and SDA. Co-expression of the two genes resulted in low-level accumulation of GLA but much larger amounts of SDA, accounting for as much to 11.64% of the total fatty acid content.     

福建平潭近海赤潮预警模型研究*

本文分析了福建省平潭近海海域2013—2019年水文、水质及气象数据的主成分结果, 筛选出5个气象因子和4个水质因子作为输入指标, 以藻密度为输出指标, 分别演算了KNN (K-nearest neighbor)、RF (random forest)、GBRT (gradient-boosted regression Trees)以及Bagging (bootstrap aggregating)4种赤潮预警回归模型。对2013—2019年的802 组海洋监测数据归一化处理后, 随机选取80%的数据作为模型的训练样本, 剩余的20%作为模型验证数据。其中, 以风速、气温、海平面气压、叶绿素a浓度组合为输入指标时, KNN回归模型演算结果的精度较高(R²=0.624, RMSE=0.821μg·L^-1, MAE=0.836μg·L^-1)。在没有叶绿素a浓度监测指标的海域, 构建了以叶绿素a浓度为输出指标, 气温、日照、风速、AOI(apparent oxygen increase)组合为输入指标的BP神经网络赤潮模型, 该模型也具有较好的预警精度(R²=0.651, RMSE=0.062μg·L^-1, MAE=0.033μg·L^-1)。本研究结果可为平潭海域的赤潮预警研究提供参考。     

Observational study of surface ozone at an urban site in East China

In this study, we present the observational data of near surface ozone and some meteorological parameters during 2004, at an urban site (36°42′ N, 117°08′ E, 34.5 m a.s.l.) of Jinan, China. Hourly ozone concentrations exceeding the standard value of China, 100 ppbv, were observed for 65 h (in 23 days) from April to October, and values exceeding US NAAQS (National Ambient Air Quality Standard) for 1 h ozone, 120 ppbv, were observed for 15 h (in 7 days) from late May to early July. Ozone formation presented the phenomenon of “weekend effect”, especially in summer. Monthly variation of ozone coincided with temperature except for July and August. The low ozone levels in July and August may be due to the short sunshine duration and much rainfall during this period. Among these meteorological parameters, daily averaged ozone shows a significant correlation with temperature (r = 0.66) in the year and with relative humidity (r = − 0.75) in summer. Throughout the year, high ozone concentrations were mainly associated with the wind from 180 to 247.5°, while high ozone concentration seemed to have no obvious correlation with a given wind direction in summer. An anomalous nocturnal high ozone episode during 23–25 May 2004 was investigated. Growth fractions of ozone during the nighttime episode were 62.2% and 71.1% for 23 and 24 May, respectively. Synoptic analysis shows that favorable synoptic condition had presumably elevated the background ozone level in this region. Backward trajectory analysis shows that the increase of ozone concentration and the relatively constant high ozone concentrations during the night of May 23 might originate from the transport of ozone rich air mass above boundary layer. Transport of ozone from Yangtze Delta and East Central China might be a significant process for the high ozone level during night May 24 at Jinan.