云南鲁史三合洞组地层时代讨论     

黄晓明  丛峰 《沉积与特提斯地质》2017,37(2):40-45

云南兰坪盆地三合洞组的时代存在争议,有早古生代和中生代两种观点。本文通过对云南鲁史上三叠统三合洞组和挖鲁八组岩石地层、古生物化石、微体化石及碎屑锆石U-Pb年代学研究,认为三合洞组时代为晚三叠世。本区三合洞组生物碎屑灰岩、泥晶灰岩及白云质灰岩与挖鲁八组炭质板岩呈整合接触关系,与歪古村组砂质板岩呈逆断层接触关系,整体表现为倒转地层。挖鲁八组炭质板岩中采获叉皱海燕蛤、虚海燕蛤等晚三叠世化石,而三合洞组灰岩中的小欣德牙形刺、奥泽克刺、滑梯螺、长卵形槽花介等微体化石时代也为晚三叠世。笔者从挖鲁八组粉砂岩中获得碎屑锆石U-Pb年龄,其最小年龄为218 Ma,指示挖鲁八组的最晚沉积时代为晚三叠世。综合生物化石和同位素年代学资料,认为兰坪盆地三合洞组的时代为晚三叠世。  相似文献   

山东省天然饰面石材花岗石和大理石地质特征及其分类          下载免费PDF全文

原明考 《山东国土资源》2017,33(3)

山东省天然饰面石材资源储量大,天然饰面石材品种多,地质成因和地质特征各有不同。通过天然饰面石材的岩石学特征对山东省天然饰面石材进行分类总结,从天然饰面石材的岩石学和矿物学角度出发,归纳山东省天然饰面石材的地质特征。通过对山东省典型天然饰面石材进行分类列举,归纳山东省典型天然饰面石材的地质特征。  相似文献   

论地理知识图谱     

陆锋  余丽  仇培元 《地球信息科学学报》2017,19(6):723-734

网络文本蕴含大量隐式地理空间信息,为地理知识获取与知识服务提供了巨大潜能。地理知识图谱是将传统地理信息服务拓展到地理知识服务的关键,也是网络文本蕴含地理信息采集与处理的终极目标。本文系统评述了开放地理语义网、开放地理实体及关系抽取、地理语义网对齐、知识图谱存储方法等地理知识图谱相关主题的研究进展,从网络文本蕴含地理空间信息量与质量评价、地理信息语义理解、空间语义计算模型和异构地理语义网对齐等方面剖析了目前亟需解决的关键科学问题。  相似文献   

有机质对纳米级磁铁矿热稳定性的影响   总被引：2，自引：1，他引：1       下载免费PDF全文

吴文芳  李金华  张春霞  潘永信 《地球物理学报》2010,53(10):2427-2434

单畴磁铁矿颗粒是地质样品中最重要的磁性载体,其稳定性一直备受关注.为了认识有机质对纳米级磁铁矿颗粒热稳定性的影响,本文对比研究了趋磁细菌AMB-1合成的单畴磁铁矿分别在全细胞中和经去胞提纯后的纯化磁小体中的热磁性质,以及热处理后样品的磁滞参数和低温磁性的变化.发现仅有磁小体膜包裹的纯化磁小体中单畴磁铁矿热稳定性极强,而全细胞中的单畴磁铁矿加热过程中发生了显著的热变化:磁铁矿在约270℃即开始转化,400℃以前几乎完全被有机质还原为顺磁性物质;同时在400℃以前,有机质的还原作用与有机质热分解引起磁小体链的坍塌,共同导致了样品矫顽力(B_c)、剩磁矫顽力(B_cr)和剩磁比(M_rs/M_s)的减小,以及矫顽力比(B_cr/B_c)的增加. 我们的实验结果清楚地表明,当地质样品中含有较多有机质组分并受热事件影响时,其中的单畴磁铁矿难以得到保存.  相似文献   

Mercury partition in the interface between a contaminated lagoon and the ocean: The role of particulate load and composition     

P. Pato  M. Otero  M. Válega  C.B. Lopes  M.E. Pereira  A.C. Duarte 《Marine pollution bulletin》2010,60(10):1658-1666

After having estimated the patterns of flow to the ocean and found some seasonal and tidal differences, mainly with regard to the relative importance of dissolved and particulate fractions, mercury partitioning at the interface between a contaminated lagoon and the Atlantic Ocean was investigated during four tidal cycles in contrasting season and tidal regimes. Mercury was found to be located predominantely in the particulate fraction throughout the year, contributing to its retention within the system. Seasonal conditions, variations in marine and fluvial signals and processes affecting bed sediment resuspension influenced the character and concentration of suspended particulate matter in the water column. Variation in the nature, levels and partitioning of organic carbon in the particulate fraction affected levels of particulate mercury as well as mercury partitioning. These results highlight the dominant role of suspended particulate matter in the distribution of anthropogenic mercury and reinforce the importance of competitive behavior related to organic carbon in mercury scavenging.  相似文献   

塔克拉玛干沙漠腹地沙尘暴过程大气颗粒物浓度及影响因素分析   总被引：1，自引：0，他引：1  

刘新春  钟玉婷  何清  艾力·买买提明 《中国沙漠》2011,31(6):1548-1553

利用Grimm1.108、Thermo RP 1400a、TSP以及CAWS-600等仪器,对2008年4月17日至23日发生在塔克拉玛干沙漠腹地的1次强沙尘暴过程的颗粒物质量浓度进行连续观测,结合天气资料分析得出:①Grimm1.108颗粒物分析仪监测结果表明,日平均浓度出现两个峰值区,主峰值出现在20日,次峰值出现在18日,而小时平均浓度高值区主要集中4月19日至20日,21日中午存在1个峰值区,其他时段浓度相对较低。②强沙尘暴发生时的分钟观测数据表明,随着风速的逐渐增强,沙尘暴强度逐渐增强,不同粒径颗粒物浓度达到最大值,>0.23 μm颗粒物总浓度为39 496.5 μg·m-3,>20.0 μm颗粒物总浓度为5 390.7 μg·m-3,随后浓度逐渐下降。③PM10和TSP的浓度变化同样反映沙尘天气的过程和强度,沙尘暴前期大气中颗粒物浓度远低于强沙尘暴期间,随沙尘天气减弱,颗粒物浓度明显下降。④沙尘天气过程中大气颗粒物浓度变化具有以下规律：晴天<浮尘天气<浮尘、扬沙天气<沙尘暴天气。风速大小直接影响大气中颗粒物浓度,风速越大颗粒物浓度越高。气温、相对湿度和气压是影响沙尘暴强度的重要因素,也间接影响大气中颗粒物浓度的变化。  相似文献   

人类活动对土壤有机碳库的影响研究进展   总被引：3，自引：1，他引：2  

崔永琴  马剑英  刘小宁  段争虎 《中国沙漠》2011,31(2):407-414

土壤有机碳库动态变化直接影响全球的碳平衡, 土壤有机碳库研究是全球碳循环研究中的关键。研究人类活动影响下的土壤有机碳库的动态特征及其过程机制,不仅可降低对未来气候预测的不确定性,也可为土壤固碳技术的选择和政策制定提供理论依据。从土地利用方式变化、耕作方式与管理两方面详尽阐述了国内外关于人类活动影响下土壤有机碳库动态的研究进展,提出应加强土地管理、采取适当的农业耕作措施来减少土壤有机碳的流失,以提高土壤对碳的固定。  相似文献   

珍珠抛光乳化蜡的研制     

李弦弦  童银洪  杜晓东  王庆恒 《广东海洋大学学报》2010,30(6)

以巴西棕榈蜡、川蜡、蜂蜡、石蜡等为原料,利用有机概念图原理,设计了珍珠抛光用蜡乳液的配方,探讨了乳化温度、乳化时间、相同配方时不同乳液类型等对乳化蜡的稳定性的影响,制作出了适合珍珠抛光的蜡乳液。结果表明:利用均质机乳化,在乳化温度95℃、乳化时间30 min、转速为1 000～2 000 r/min时,所配制的珍珠抛光乳液稳定性较好,对提高珍珠光泽具有明显效果。  相似文献   

Kinetic Modelling of the Removal of Seven Common Pollutants in Subsurface Flow Constructed Wetlands     

SUN Guangzhi  Antony Ladson 《湿地科学》2010,8(4)

The main removal mechanisms for the degradations of seven pollutants in wastewater treatment wetlands were analysed, and a mathematical model was established to quantify the removal of each pollutant, based on its main removal mechanisms. Subsurface horizontal flow wetlands were treated as a series of continuous stirred - tank reactors (CSTRs). Kinetic models for the removal of biochemical oxygen demand, chemical oxygen demand, ammonia, total nitrogen and faecal coliforms were established by combining Monod or first - order kinetics with CSTR assumptions. These tentative models account for a wide range of factors that affect wetland performance, but the models have not been proven by ex periment data. Depending on the derivation of various coefficients in the models and verification by actual performance data, this study may provide a starting point for an integrated pollutant removal model to be developed, and experimen tally verified, thereby making a step forward from the current greenbox' approach of wetland design.  相似文献   

Changes in soil and vegetation on moving sand dunes after exclosure in Horqin Sandy Land, Northern China     

YuLin Li  JianYuan Cui  XueYong Zhao  YongZhong Su 《寒旱区科学》2010,2(4):0335-0344

In the semiarid Horqin Sandy Land of northern China, land desertification is the main causation in vegetation degradation and formation of moving dunes. A study was conducted from 1996 to 2005 to monitor the changes of vegetation characteristics and soil properties after moving dunes were fenced. The changes were compared between moving sand dunes with exclosure and without exclosure to evaluate the effectiveness of vegetation and soil restoration after exclosure establishment. The results show that exlosure establishment facilitated the colonization and development of plant species by ameliorating stressful environmental conditions. Species diversity, average coverage, and plant density significantly increased after exclosure of moving sand dunes along sequence compared with sand dunes without exclosure. Vegetation recovery on moving sand dunes accelerated by exclosure resulted in significant changes in soil properties including increased silt and clay contents, organic C and total N and decreased sand content, especially at the 0-5 cm depth. The results implied that moving sand dunes can be rapidly fixed by construction of exclosure.  相似文献