“天堂山地体”初探

文章提出天堂山地体是一个由变形变质花岗岩和变质表壳岩组成的变质地体,形成了寒武纪东吴运动,天堂山地体右旋扭动向北运动,最终与钦州地体发生拼合,两地体之间的构造分界线是灵山构造带。     

Generating and mapping population density surfaces within a geographical information system

Some alternative ways of presenting maps of spatial population distribution are examined using northern Leicestershire, England, as an example. The authors conclude that dasymetric and isarithmic maps are a desirable alternative and can be relatively easily generated using satellite imagery in a geographical information system.     

广西岑溪地区泥盆系志留系地质特征及其意义

广西岑溪地区志留系为半深,深海笔石相－滨浅海腕足相的碎屑岩地层序列,属地槽型沉积产物;泥盆系为滨岸碎屑岩相－台地碳酸盐岩相－槽盆硅质岩相的地层序列,富含鱼,腕足等多门类化石,具地台型沉积特征,泥盆系与志留系之间为平行不整事接触,表明广西运行在本区表现国整体抬升遭受剥蚀而非强烈的造山运动,其集中暴发时间在早泥盆世早期,前奏可追溯到中志留世。由于这一运动,结束了本区早古生代地槽的发展历史,此后进入准地     

应用水平井地质数据进行油藏描述：北海南部Lancelot地区赤底统砂岩的实例

Ｌａｎｃｅｌｏｔ,Ｇｕｉｎｅｖｅｒｅ,Ｅｘｃａｌｉｂｕｒ是主要靠水平培开发的一组气田,这些气田的水平井数据及其解释与垂直井数据相结合,用于评价目标区和强化储层描述。根据水平井岩芯可对储层质量的晚期变化和风成相进行解释。井下成像和常规电测井用于识别岩相,记录风成沙丘交错层组的晚期延伸和定位,表征成岩趋向,定位水平井未取芯部分中的裂缝。     

修正破裂时间法在南加州中期地震预测中的应用

基于南加州地震目录以及早先公布的新马德里地震带的连续地震记录。利用修正破裂时间法作为中晚期地震预测技术来预测未来主震的位置,震级和时间,对早先地震的预测表明,这个方法预测的主震震级误差近似于±０．５级,假定最后前兆事件已知,误差与破裂时间一致,接近±１．１年,当最后前兆事件未知,预测震级保持较小,但预测时间随着序列中事件的增加还需要修正,主震的位置也可以在半径数十公里量级的圆形区域中确认,为确定加     

Mussel farming as a nutrient reduction measure in the Baltic Sea: consideration of nutrient biogeochemical cycles

Nutrient loads from the land to the sea must be reduced to combat coastal eutrophication. It has been suggested that further mitigation efforts are needed in the brackish Baltic Sea to decrease nutrients, especially in eutrophic coastal areas. Mussel farming is a potential measure to remove nutrients directly from the sea. Mussels consume phytoplankton containing nitrogen (N) and phosphorus (P); when the mussels are harvested these nutrients are removed from the aquatic system. However, sedimentation of organic material in faeces and pseudo-faeces below a mussel farm consumes oxygen and can lead to hypoxic or even anoxic sediments causing an increased sediment release of ammonium and phosphate. Moreover, N losses from denitrification can be reduced due to low oxygen and reduced numbers of bioturbating organisms. To reveal if mussel farming is a cost-effective mitigation measure in the Baltic Sea the potential for enhanced sediment nutrient release must be assessed.