电磁排列剖面法（EMAP）原理及应用

电磁排列剖面法是在MT法基础上发展起来的一种新方法,其工作效率高,横向分辨率强,可减少“静态效应”对测深曲线的畸变。在近几年油气勘探中取得比较好的地质效果并深受重视。作为一种新方法有很多问题需要研究,就方法的原理、仪器、野外采样及推断解释做了初步总结     

Sampling efforts for estimating fish species richness in western USA river sites

Fish species richness is an important indicator of river ecological condition but it is particularly difficult to estimate in large unwadeable rapidly flowing rivers. Intensive multi-gear sampling is time consuming, logistically complex and expensive. However, insufficient sampling effort underestimates species richness and yields inaccurate data about the ecological condition of river sites. We raft-electrofished 10 large river sites in 10 different ecoregions and six western USA states for distances equal to 300 times their mean wetted channel widths (MCWs) to estimate the effort needed to approach asymptotes in fish species richness. To collect 90% of the observed fish species at the sites, we found that an average of 150 MCWs (ranging 80–210 MCWs) were needed, with the number of MCWs increasing in rivers with a higher proportion of spatially rare species. Frequently, the second or third additional 100 MCWs produced only one or two additional singletons or doubletons (species occurring only once or twice at a site). Before initiating sampling programs for estimating species richness, we recommend assessing sampling effort, particularly if rare or uncommon species are expected or desired.     

电磁阵列剖面法(EMAP)在阿尔凹陷构造研究中的应用

∶本文论述了电磁阵列剖面法(EMAP)在二连浩特地区阿尔凹陷岩性分层、断裂及基底构造研究中的应用.采用电磁阵列EMAP测量,有效的避免了静态位移难以有效校正等问题.通过有效的资料处理,反映了阿尔凹陷地层结构特征与空间展布,落实了凹陷的基底埋深,对区内控陷断层的位置、性质、展布及发育特征进行了划分,达到了较好的预期效果,为勘探空白区油气远景预测提供了可靠的基础资料.     

A benthic index of biological integrity for assessing habitat quality in estuaries of the southeastern USA

A benthic index of biotic integrity was developed for use in estuaries of the southeastern USA (Cape Henry, VA; St. Lucie Inlet, FL) using a modification of the method developed by Weisberg et al. (1997. An estuarine benthic index of biotic integrity (B-IBI) for Chesapeake Bay. Estuaries, 20 (1), 149–158). Data from non-degraded stations sampled in 1993 and 1994 were analyzed using classification analysis of species composition to define major habitat types relative to selected physical parameters. Various benthic metrics were then tested on a larger 1994 data set for each major habitat to determine those that discriminated between non-degraded and degraded sites classified on the basis of dissolved oxygen, sediment chemistry, and sediment toxicity results. Scoring criteria for each metric were developed based on the distribution of values at non-degraded sites. Average scores from different combinations of the most sensitive metrics were compared to derive the final index, which integrates the average scores of four metrics (number of taxa, abundance, dominance, and percent sensitive taxa). An independent data set representing sites sampled in 1993 and 1995 was used to validate the index. The final combined index correctly classified 93% of stations province-wide in the developmental data set and 75% of stations in the validation data set. Comparison of the index results with those of individual benthic measures and sediment bioassays from stations sampled in 1993 and 1995 showed that the index detected a higher percentage of samples where bioeffects were expected (based on sediment chemistry) than did any of these other measures individually.     

哈尔滨-尚志MT阵列剖面研究

根据哈尔滨-尚志连续电磁剖面测深结果,研究了松辽盆地东缘盆山结合部的地质结构特征,尤其是对深层的地质结构取得了重要的认识.盆山结合部划分出3个基本单元:松辽盆地、滨东隆起区和张广才岭隆起区.盆地一侧的盖层具有双重结构.盆地具双重基底,即浅变质岩的褶皱基底与侵入岩的结晶基底.莫霍面在盆地一侧隆起,向张广才岭变深,隆起幅度4km.断裂主要为岩石圈与壳断裂,对构造单元起控制作用.