鲁西地区太古宙绿岩带硫铁矿床地质特征及成矿机制     

司双印  孙茂田 《化工矿产地质》2001,23(2):86-92

鲁西地区新太古代雁翎关组由科马提岩、角闪质岩石、变粒岩和含铁石英岩等组成 ,其原岩为一套超镁铁质镁铁质火山熔岩及火山碎屑沉积的表壳岩建造 ,经历了三期区域变质作用 ,变质程度达低角闪岩相 ,是华北地台上一个典型的绿岩带。鲁西花岗岩绿岩带中分布有大小黄铁矿脉数十条之多 ,呈层状、透镜状或脉状沿片麻理方向展布 ,硫品位 3 .79%～ 3 1.6% ,伴生有用组分Fe、Ni、Ag等。通过对绿岩、矿体和矿石特征、S、Fe分布及变质成矿作用等方面的研究 ,证实绿岩中含有丰富的S、Fe、Ni等造矿元素 ,认为绿岩既是赋矿岩石亦是矿源层 ,矿床属变质热液叠加的变质火山沉积型硫铁矿床。  相似文献   

有关地形通视分析问题的研究和探讨     

田金蓉  汉斯 《测绘学院学报》1992,(3)

本文通过对地形通视分析的基本设想的描述及其实践途径中有关问题的探讨,结合实例阐明了计算机自动进行通视分析的基本方法和处理技巧,并附有具体程序。  相似文献   

The status of the ecological environment and a proposed protection strategy in Sanya Bay,Hainan Island,China   总被引：8，自引：0，他引：8  

Huang L  Tan Y  Song X  Huang X  Wang H  Zhang S  Dong J  Chen R 《Marine pollution bulletin》2003,47(1-6):180-186

Sanya Bay encompasses a high diversity of natural habitats, ranging from coral reefs, rocky and sandy shores and mudflats to mangroves. Seasonal physicochemical and biological investigations were conducted from 1998 to 1999 and again in April 2000. Water-related environmental quality in Sanya Bay is in good condition. The levels of dissolved oxygen, nitrogen, phosphorus and heavy metals are within the first class of National Seawater Quality Standards for China. Annual mean values of chlorophyll a of 0.93 mg m(-3) and phytoplankton primary productivity of 440.8 mgC m(-2)d(-1), respectively, were found in the waters, both of which show a significant correlation with inorganic nitrogen. A mean new productivity of 144.6 mgC m(-2) d(-1) was recorded in summer. Sanya Bay is rich in natural resources and biodiversity with 235 species of phytoplankton and 129 species of zooplankton identified in the survey. The annual mean abundance of phytoplankton and zooplankton were 1564 x 10 cells m(-3) and 121 individuals m(-3), respectively, with an annual mean zooplankton biomass of 129 mg m(-3). A total of 243 species of fish were sampled in the survey including many of high economic value. Three hundred and eighty-four species of benthos in 121 families were found by mud sampling and trawling. The average biomass of benthic organisms was 11.55 gm(-2), with a density of 31 individuals m(-2). Molluscs were the dominant group, followed by crustaceans; coelenterates exhibited the lowest biomass. One hundred and twenty-six species from 48 families of intertidal organisms were collected by frame sampling, with a mean annual biomass of 644.7 gm(-2) and average density of 816 individuals m(-2). The highest biomass of 1673.5 gm(-2) was collected in a coral reef region, while the highest density of 1219 individuals m(-2) occurred in a mangrove region. The coastline is characterized by coral reefs that accounts for 30% of the total coastline length in the bay, so coral reefs are a key ecosystem that are important for maintaining the regional marine resources and biodiversity. We need to pay much more attention to such diverse marine resources to maintain the integrity and function of these coastal ecosystems.  相似文献   

断陷湖盆隐蔽油藏预测及勘探的关键技术--高精度地震探测基础上的层序地层学研究   总被引：82，自引：6，他引：76  

李思田  潘元林等 《地球科学》2002,27(5):592-598

近十余年世界的我国隐蔽油藏勘探取得了巨大进展,其关键技术是高精度的三维地震及在此基础上的层序地层学研究,二者的结合已被油气产业部门当作勘探中的“权威性技术”。断陷湖盆在我国东部含油气资源的重要性居首位,控制层序形成演化的诸因素中,构造,古气候和在区域古地理格局中的位置对湖盆的类型和演化起着决定作用,需要按照断陷湖盆的沉积构造演化特征建立有预测功能的层序构成模式,在成熟的勘探区,重新建立等时层序地层格架,进行体系域精度的工业制图,阐明沉积体系的分布规律,使用高精度地球物理技术对圈闭定位,并对构造坡折带和低位域扇体给予重点注意,用这种技术方法指导隐蔽油气藏的勘探,已经并必将有许多重要发现。  相似文献   

焦作市4—9月短期降水精细化预报系统   总被引：2，自引：0，他引：2  

司福意  刘跃红  黄克磊  罗楠  李艳红  苗卫东 《气象》2006,32(8):77-80

在降水时空变化研究的基础上，完成辖区降水区划；用计算机识别T213风场中槽线、切变线等影响系统，并按其相对于预报站方位，确定对其影响强度指数，组合预报因子，建立判别方程，制作分县0～12小时、12～24小时降水分级预报。经检验，系统对降水落区有较强预报能力。  相似文献   

Reducing standard errors by incorporating spatial autocorrelation into a measurement scheme for soil carbon credits     

Siân Mooney  Ken Gerow  John Antle  Susan Capalbo  Keith Paustian 《Climatic change》2007,80(1-2):55-72

Several studies have suggested that geostatistical techniques could be employed to reduce overall transactions costs associated with contracting for soil C credits by increasing the efficacy of sampling protocols used to measure C-credits. In this paper, we show how information about the range of spatial autocorrelation can be used in a measurement scheme to reduce the size of the confidence intervals that bound estimates of the mean number of C-credits generated per hectare. A tighter confidence interval around the mean number of C-credits sequestered could increase producer payments for each hectare enrolled in a contract to supply C-credits. An empirical application to dry land cropping systems in three regions of Montana shows that information about the spatial autocorrelation exhibited by soil C could be extremely valuable for reducing transactions costs associated with contracts for C-credits but the benefits are not uniform across all regions or cropping systems. Accounting for spatial autocorrelation greatly reduced the standard errors and narrowed the confidence intervals associated with sample estimates of the mean number of C-credits produced per hectare. For the payment mechanism considered in this paper, tighter confidence intervals around the mean number of C-credits created per hectare enrolled could increase producer payments by more than 100 percent under a C-contract.  相似文献   

菏泽市夏季对流天气预报方法     

魏秀兰  司奉泰  程德海 《山东气象》2007,27(2):22-24

利用2004-2005年4-9月逐日常规高空格点资料，根据产生对流天气的三个基本条件，即水汽条件、不稳定层结条件和抬升力条件，进行因子的选取和组合，用逐步回归方法建立了各县市12～24小时客观预报方程，利用VB6．0编程，自动调取资料选取因子，将计算结果显示，实现了自动化，经试用，效果较好。  相似文献   

星载加速度计的动力法校准   总被引：1，自引：0，他引：1  

邹贤才  李建成  罗佳  徐新禹 《武汉大学学报(信息科学版)》2007,32(12):1152-1155

通过模拟轨道，利用动力法对星载加速度计校准进行了研究。用不同参考重力场模型获得的校准参数分别重新积分卫星轨道，与模拟轨道的差异最大可达m级。结果表明，参考重力场模型误差对加速度计校准的影响不可忽略，在校准加速度计的同时应解算重力场模型，以削弱模型误差的影响。  相似文献   

蒙阴县苏家沟科马提岩     

张荣隋  司荣军  宋炳忠  刘述敏 《山东国土资源》1998,(1)

苏家沟科马提岩呈透镜状残留体赋存于早元古代二长花岗岩中,主要由蛇纹石化橄榄科马提岩、透闪石岩、透闪片岩、阳起透闪片岩、绿泥透闪片岩、黑云阳起片岩等组成,具典型的鬣刺结构及变余鬣刺结构。该科马提岩的岩石学、岩石化学及结构特征与世界典型地区科马提岩极为相似,属橄榄科马提岩。  相似文献   

陕西金堆城斑岩钼矿床成矿流体研究   总被引：18，自引：0，他引：18  

徐兆文  杨荣勇 《高校地质学报》1998,4(4):423-431

陕西金堆城斑岩钼矿床是中国最大的钼矿床之一,按照脉体相互切割关系,成矿过程可分为两期十个阶段。矿区内流体包裹体研究表明：成矿流体以富CO2为特征,温度介于83℃～142℃之间,盐度介于27.5～42.5wt％NaCl两个区间内,具有典型的双配分模式特征。氢氧同位素特征研究表明成矿物质主要来源于岩浆流体。晚阶段有大量雨水混入热液流体中,导致流体的温度、盐度和δ18OH2O、δD值下降,引起了成矿流体中的钼金属沉淀,形成了金堆城超大型斑岩钼矿床。  相似文献