多边形平差法计算的改进建议

《测绘通报》一九六四年第一期《B．B．波波夫多边形平差法计算表格的改进》中提出的平差计算表格，对于实际运用是很方便的。但是该表在逐次趋近计算中，各环用于配赋的闭合差是根据上一次趋近求得的高差改正数来计     

Research progress on methylmercury in the cryosphere北大核心CSCD

The cryosphere is one of the climate system component which plays an important role in the global biogeochemical mercury cycling. Anthropogenic mercury has been transported to remote cold and high regions worldwide through atmospheric circulation,and then transformed into methylmercury in the cryosphere. As one of the highly toxic environmental pollutants,methylmercury can be greatly bioaccumulated and biomagnified through the food web,which potentially poses threats to human and wildlife as well as the global cryospheric en⁃ vironments. In order to gain a full picture of research progress on methylmercury in the cryosphere,our study comprehensively summarized the concentration levels and analytical methods of methylmercury,and biogeo⁃ chemical processes such as the migration,transformation and fate of methylmercury in various cryospheric envi⁃ ronments including glacier,permafrost,snow ice and sea ice. We particularly made the literature review of mi⁃ crobial mercury methylation and evaluated the risk of methylmercury exposure to human and wildlife in the cryo⁃ sphere. Meanwhile,we focus on distribution,behavior,and environmental effects of methylmercury in the cryosphere against the backdrop of climate change,which is essential for assessing the exposure risk of methyl⁃ mercury to humans and wildlife. Perspectives of methylmercury researches in the cryosphere have also been highlighted in this review,though there is existing a knowledge gap of biogeochemical methylmercury cycling in the low temperature environments which merits further study. © 2023 The Author(s).     

华北束鹿凹陷斜坡带沙河街组油气藏分布规律与区带成藏模式

在系统阐述冀中坳陷南部束鹿凹陷斜坡带成藏条件的基础上, 探讨了油气藏的分布规律、不同区带成藏模式及主控因素。研究表明, 斜坡带主要发育4种类型油气藏, 斜坡北、中、南段成藏条件与模式不同; 斜坡内外两带成藏规律与油气藏类型不同, 其中斜坡中部西曹固构造带具有连片成藏的优良条件, 而沟通油源的深大断裂形成的断块是优先成藏的有利区带。      

冀中坳陷蠡县斜坡古近系沙一下亚段沉积物源分析*

基于对冀中坳陷饶阳凹陷蠡县斜坡碎屑岩分析化验资料,结合该区古水系与古地貌特征,从岩样的碎屑组分、岩屑类型、重矿物组合与ZTR指数及地震剖面反射特征等方面,对古近系沙河街组一段下亚段(沙一下亚段)沉积的物源方向进行综合研究。结果表明:蠡县斜坡古近系沙一下亚段的沉积物主要来自于斜坡西南部和北部,其中西南部物源区主要位于太行山隆起,沉积物分别由古大沙河经由斜坡南部及古唐河越过高阳低凸起运移进入斜坡,是主要物源;北部物源主要来自牛驼镇低凸起,是次要物源。西南部物源与北部物源交汇于蠡县斜坡东部西柳地区。     

南海西北部表层沉积物黏土矿物分布特征及其来源

黏土矿物研究在示踪物源、源区风化历史乃至洋流变迁能力等方面具有重要的作用,尽管目前对南海表层沉积物黏土矿物宏观分布特征已获得了较系统的认识,但在受珠江和海南岛物源共同影响的南海西北部其高分辨率的黏土矿物学工作还未开展。本文对南海西北部表层沉积物中的黏土矿物组成、结晶学特征进行了分析,讨论了研究区黏土矿物的物质来源。结果表明,南海西北部表层沉积物的黏土矿物组成以伊利石为主（平均45%）,蒙脱石（平均27%）与高岭石（平均21%）次之,绿泥石含量最少（平均6%）。在区域空间分布上,蒙脱石含量呈现西南高东北低的特征,伊利石含量则与之相反;高岭石含量表现为近岸高离岸低,而绿泥石含量呈现离岸高近岸低的特征。总体上,研究区表层沉积物黏土矿物组成与现代珠江沉积物组成差异较大,而与珠江口2.5 ka前的沉积物黏土矿物组成比较接近,并且结合研究区岩心揭露的全新世以来极低的沉积速率（4 cm/ka）以及上部很薄（小于0.6 m）的泥质沉积,推测该区表层沉积物可能并非是现代沉积的结果,更可能主要来自全新世末期古珠江输送的沉积物。除古珠江作为研究区表层沉积物中蒙脱石的一个主要来源外,海南岛北部河流也贡献了少量蒙脱石到其邻近的东南海域。运用高岭石/伊利石比值和伊利石化学指数等进一步对比分析表明,珠江是研究区沉积物中伊利石、高岭石和绿泥石的主要物源,其次台湾和海南岛也可能分别提供了少量富含伊利石/绿泥石和高岭石的沉积物。本工作对于南海西北部沉积物源-汇过程和相应的古环境研究有重要的参考意义。