曹妃甸地区地下水水化学特征及影响因素的R型因子分析

通过对2008年12月份在曹妃甸地区采集测试的25组水化学资料进行分析,探讨了该区地下水的水化学特征,并利用R型因子分析法对影响该区地下水化学组分的4个主要因素进行了研究,结果表明:区内浅层地下水基本都为高矿化的Cl-Na型,深层地下水水化学类型具有一定的水平分带性;高矿化的地表水和潜水主要是蒸发浓缩作用和沿海土壤易溶盐含量高共同影响的结果,深层地下水水化学组分主要受含水介质中易溶盐分组成和补给水高碳酸含量的影响;地下水中NH4+、NO3-和NO2-的广泛检出反映了农业生产和人们生活排污等人类活动对地下水化学组分的影响。     

Correlations between radiometric analysis of Quaternary deposits and the chronology of prehistoric settlements from the southeastern Brazilian coast

Natural gamma radiation measurements of sand deposits were carried out in order to study the chronology of prehistoric colonization of the Brazilian coast during the Holocene. The method employs thorium, uranium and potassium as tracers of the geological provenance of Quaternary deposits, where artificial shellmounds are found. The so-called sambaquis are archaeological settlements, characteristic of fisher-gatherers, specialized in the exploitation of shellfish. Our results show a considerable positive correlation between the formation of coastal deposits, based on cross plots of eTh/eU and eTh/K, and the antiquity of its prehistoric human occupation.     

Application of radiometric analysis in the study of provenance and transport processes of Brazilian coastal sediments

Natural gamma radiation of beach sand deposits was measured along the south coast of Rio de Janeiro State, Brazil, with the aim of studying the provenance and transport processes of sediments in this area. Concentrations of thorium, uranium and potassium were evaluated using γ-ray spectrometry and a behavioral study of eTh/eU and eTh/K cross plots was performed, reflecting the mineralogical properties of beach sands, as well as their history of transport and sorting processes. The results show that such technique can be efficiently used to map heavy mineral distributions and to distinguish the different origins of coastal sediments disclosing the influence of nearby rivers.     

四川西部黄土沉积与环境演变研究综述

四川西部(川西)地处青藏高原东部,黄土广泛分布于河谷和断陷盆地中.该地区黄土的主体属风成堆积,为附近及高原内部地区的冰川沉积、寒冻风化物、河湖沉积、风沙沉积和坡积物等多种沉积物中的细粒物质,在西风、高原冬季风和近地面风的搬运下堆积而成.局部有受坡面流水作用形成的次生黄土.最早的黄土堆积始于早更新世(1150ka),现主...     

Synthesis of branched para-nonylphenol isomers: occurrence and quantification in two commercial mixtures

Eight tertiary nonanols were synthesized via Grignard reaction and coupled by Friedel–Crafts alkylation with phenol to the corresponding nonylphenols. Six branched para-nonylphenols (NP) were obtained: 4-(3′-methyl-3′-octyl)phenol (33NP), 4-(2′-methyl-2′-octyl)phenol (22NP), 4-(2′,5′-dimethyl-2′-heptyl)phenol (252NP), 4-(2′,5′,5′-trimethyl-2′-hexyl)phenol (2552NP), 4-(2′,4′-dimethyl-2′-heptyl)phenol (242NP) and 4-(4′-ethyl-2′-methyl-2′-hexyl)phenol (4E22NP). Their structures were confirmed by GC–MS and NMR spectroscopy. These six isomers as well as the earlier synthesized 4-(3′,5′-dimethyl-3′-heptyl)phenol (353NP), 4-(3′,6′-dimethyl-3′-heptyl)phenol (363NP) and 4-(2′,6′-dimethyl-2′-heptyl)phenol (262NP) were compared with commercial NP mixtures purchased from Acros and Fluka by GC–MS (equipped with a 100 m polysiloxane column). The analyses revealed that all obtained isomers are occurring in different quantities in both commercial NP mixtures.     

A 2.5‐million‐year perspective on coarse‐filter strategies for conserving nature's stage

Climate change will require novel conservation strategies. One such tactic is a coarse‐filter approach that focuses on conserving nature's stage (CNS) rather than the actors (individual species). However, there is a temporal mismatch between the long‐term goals of conservation and the short‐term nature of most ecological studies, which leaves many assumptions untested. Paleoecology provides a valuable perspective on coarse‐filter strategies by marshaling the natural experiments of the past to contextualize extinction risk due to the emerging impacts of climate change and anthropogenic threats. We reviewed examples from the paleoecological record that highlight the strengths, opportunities, and caveats of a CNS approach. We focused on the near‐time geological past of the Quaternary, during which species were subjected to widespread changes in climate and concomitant changes in the physical environment in general. Species experienced a range of individualistic responses to these changes, including community turnover and novel associations, extinction and speciation, range shifts, changes in local richness and evenness, and both equilibrium and disequilibrium responses. Due to the dynamic nature of species responses to Quaternary climate change, a coarse‐filter strategy may be appropriate for many taxa because it can accommodate dynamic processes. However, conservationists should also consider that the persistence of landforms varies across space and time, which could have potential long‐term consequences for geodiversity and thus biodiversity.     

郯庐断裂带江苏段第四纪活动特征及其动力学背景探讨

本文通过对郯庐断裂带江苏段开展的野外调查、深部构造和运动学特征等方面的研究,结合近年来最新的研究成果,对郯庐断裂带江苏段的第四纪活动特征及其动力学背景进行了探讨.邦庐断裂带江苏段第四纪活动具有东强西弱、北强南弱的特征;郯庐断裂带第四纪的逆冲活动主要受西太平洋弧后扩张的动力学因素控制;南华北与北华北地块深部构造特征和新构...     

应用高密度电法探测北京南口-孙河隐伏断裂

举例说明了高密度电法在北京南口-孙河活隐伏活动断层勘测中的应用,展现高密度电法在断层定位中的广阔应用前景。简单介绍了高密度电法的基本原理。视电阻率异常剖面揭示南口-孙河断裂为正断层,北东盘上升,南西盘下降,推测断裂倾角60°～68°。视电阻率异常剖面与钻孔资料对应较好,并与钻探资料分析的断裂活动特性基本吻合。     

浅层地震技术在九江-黄梅长江冲积平原第四纪研究中的应用

在九江—黄梅长江冲积平原第四纪研究中运用浅层地震技术,于江西九江港口镇—湖北黄梅县新开镇段实测一条物探剖面,经过对横波反射、瑞雷面波、横波折射、电测深等物探资料的分析,结合区域地质、钻探记录进行综合研究,确定了5个地震波组,发现一组第四系断层,划分了四个主要地震地质层(Ⅱ—Ⅳ),为长江两岸第四纪沉积环境演化提供新材料。     

浙江湖州市青铜桥ZK01孔第四系沉积物磁性特征和古环境意义

通过对湖州市青铜桥ZK01孔第四系沉积物系统磁性参数测量及分析研究，发现根据磁参数的比值对沉积物中磁性矿物颗粒大小和成分的分析结果，与根据磁化率（k）、饱和等温剩磁（SIRM）、饱和剩磁矫顽力{（Bo）cr}的分析获得的结果两者有较好的一致性。ZK01孔以24．7m为界，上部磁性矿物浓度高、磁性矿物成分单一，磁性颗粒粒度变化不大；下部磁性矿物浓度低（底部除外），磁性矿物成分和磁性颗粒粒度变化大，沉积物中有多相磁性矿物的存在，并含有超顺磁晶粒混合物。ZK01孔剖面跨越了布容一松山极性带界线，在布容正向极性期，存在2个次级极性倒转事件。剖面可分出五个明显不同的磁性地层段，可能分别对应于不同时期的古气候条件。为进一步查清研究地区第四系地层结构、地层的划分和对比具重要意义。