致密砂岩气成藏机制类型及特征研究

致密砂岩气是一种重要的非常规天然气资源,并且在我国其储量占全国天然气总储量的比例较大。系统的研究致密砂岩气藏的成藏机制有助于划分气藏类型,确定勘探方向,提高天然气产量。本文通过大量的文献调研,对比分析不同致密砂岩气藏在成藏过程中天然气的运移模式,根据气体运移动力的种类,提出了"活塞充注型致密砂岩气藏"、"混合驱替型致密砂岩气藏"及"置换聚拢型致密砂岩气藏"三种成藏类型,并阐述其地质特征。     

基于县域单元的武汉城市圈经济时空差异研究

将传统统计分析方法与ESDA方法相结合,借助OpenGeoda1.0和ArcGIS9.3,以县域为研究单元,以人均GDP为测度指标,从时间、空间和关联性三个侧面对1996~2010年武汉城市圈县域经济差异的空间格局及演化进行了分析。结果表明,武汉城市圈县域经济存在明显的全局空间正相关性,且具有持续增强的趋势;区域经济初步表现出"二元结构"发展特征,以武汉市为中心的经济高值区辐射效应较弱,极化作用显著;"俱乐部趋同"现象在武汉城市圈县域经济发展中初步显现。着重分析了区域发展战略对武汉城市圈经济发展水平空间格局演变的驱动作用。     

镭同位素在海洋学研究中的应用及进展

镭同位素具有不同的半衰期,可以用来研究不同时空尺度的海洋学过程,在海洋学研究中得以广泛应用。镭同位素在海洋学中的应用主要包括溶解态物质输运,水体停留时间的估算,海洋地下水排放,沉积物的地球化学和放射年代学以及海洋水团分析5个方面的内容。从海洋中镭同位素的地球化学行为、测量方法及其在以上5个方面的研究综述了镭同位素海洋学研究进展,比较了海洋中镭同位素测量方法,阐释了各应用领域的示踪原理,给出各种应用的方法模式及公式,总结了镭同位素海洋学的发展变化,并指出我国镭同位素海洋学的发展前景和方向。     

UBII:一种协同经济、社会与人类活动的城市边界识别指数

城市边界识别是测度城市规模的关键,也是研究城市问题的基础。本文在借鉴了国内外已有的研究基础上提出了一种新的综合经济因素、社会因素、人类活动强度和范围的城市边界识别指数UBII(Urban boundary i-dentification index),即用经济密度、人口密度、夜光强度和出行时间4种参数构建指数来识别城市边界并提取城市建成区范围。本文将对此指数和城市边界识别方法进行介绍,并选取中国湖北省作为实验区,讨论了UBII的合理阈值,进行了不同方法下的城市边界识别对比分析以及不同发展阶段城市的适用性分析。结果表明:使用UBII进行城市边界识别具有较高的准确性,识别结果更为客观;对于不同发展阶段的城市均有一定的适用性,识别结果更为精确。     

Preliminary study on particulate organic carbon export fluxes in the Bering Sea

During the Second Chinese National Arctic Expedition (CHINARE) from July to September 2003, depth profiles of dissolved and particulate 234Th in upper water columns were collected at two stations of BR03 and BR24 in the Bering Sea. 234Th was sampled by using a traditional Fe(OH)3 co-precipitation technique, which is a reliable approach to 234Th measurement. We observed 234Th excess at station BR03 below the euphotic zone, which was possibly due to the intensive remineralization of particulate matter. Particulate organic carbon (POC) export fluxes were estimated from a one-dimensional irreversible steady state model of 234Th fluxes together with measurements of the POC/234Th ratio on the suspended particles. The POC export fluxes from the euphotic zone were 11.66 and 11.69 mmol C m-2 d-1 at BR03 and BR24 stations,respectively. The ratios of POC fluxes to primary production at the two stations were about 0.5 and 0.59, respectively, probably due to the presence of large phytoplankton (in particular diatoms).     

楚科奇海陆架重金属沉积研究

采用Pb-Po法测定了楚科奇海陆架沉积物中210Pb的垂直剖面.应用双层模型研究210Pb分布,得到沉积速率(S)为0.145cm/a,沉积物堆积通量(FM)为78mg/(cm2·a),过剩210Pbex的沉积通量为6×10-3Bq/(cm2·a)[即0.36dpm/(cm2·a)].用中子活化分析方法和火焰原子吸收法分析测定了沉积物岩芯12个层段的重金属Cu、Pb、Zn、Cd、Cr、Co、Fe、Mn和V的含量,发现各层段之间重金属含量没有显著的区别.将本次分析结果和北冰洋其他一些陆架区的研究结果及页岩标准值相比较,发现楚科奇海沉积物中大部分重金属含量都相对较低.基于此可以推断,楚科奇海沉积物中重金属是源于地球化学过程的作用,没有表现出受到明显的人为重金属污染影响.     

Vertical flux of particulate organic carbon in the central South China Sea estimated from 234Th-238U disequilibria

^234Th-^238U disequilibria were applied to examine the particle dynamics in the euphotic zone of the central South China Sea during the spring 2002 cruise. The particulate organic carbon （POC）, ^234Th （including both dissolved and particulate） and ^238U in the water column at three stations were determined. The profiles of ^234Th/^238U activity ratio at the three stations all showed consistent ^234Th deficit as compared to ^238U in the upper 100 m water column. Based on the profiles of the dissolved and particulate ^234Th and a steady state box model, the dissolved ^234Th scavenging rates, the particulate ^234Th removal rates and their resident times were quantified. It was found that the POC downward export fluxes out of the upper 100 m euphotic zone ranged from 9.40 to 14.78 mmol·m^-2·d^-1. The results from this study provide new information for our understanding of carbon biogeochemical cycle in the South China Sea.