U-Th-Pb dating of garnet based on LAICP-MS mapping technology: A case study of the Tonglvshan large-scale Cu -Fe-Au skarn depositSCIEI北大核心CSCD     

葛粲  汤笑伟  汪方跃  李修钰  孙贺  顾海欧  袁峰  郑辉 《岩石学报》2023,(10):2879-2894

矽卡岩矿床的年代学信息对研究矽卡岩矿床的矿床成因、演变过程、成矿规律和找矿勘查具有重要的指示意义。石榴子石是矽卡岩矿床中的常见矿物,它具有一定的U含量,但是由于其普通铅高以及铀分布不均一的原因,导致激光剥蚀电感耦合等离子体质谱仪(LA-ICP-MS)点分析获得年龄成功率不高。针对点分析定年遇到的深度分馏和剥蚀点选取、普通铅校正等问题,本文提出一种利用LA-ICP-MS面扫描分析数据的虚拟点构建技术,在Tera-Wasserburg(TW)图中实现普通铅校正来确定含普通铅石榴子石年龄。通过理论推导、数值模拟和实验分析研究发现,利用相关联的^(208)Pb、^(232)Th、^(238)U测量数据校正生成^(208)Pb_(c)/^(238)U指标并据此对TW图中的数据进行数据分组抽样构造虚拟测量点,可以有效地把面扫描测量数据转换为与点分析测量类似但放射母子比例展布更优的数据。利用此方法对长江中下游成矿带鄂东矿区铜绿山大型Cu-Fe-Au矽卡岩矿床石榴子石进行面扫描分析。仅使用15min的样品面扫描数据,在获得了微量元素含量分布的同时,也获得了同位素比值虚拟点,交点年龄为139.2±2.9Ma(MSWD=0.7,n=126),与前人矿床研究结果相一致,验证了此方法的可行性。利用LA-ICP-MS面扫描定年技术不仅可以获得样品元素含量的二维分布图,有利于对样品期次的筛选,剔除包裹体等异常数据;还可以避免点分析中深度分馏和繁复的选点流程及二次分析等步骤,在获得样品元素含量分布的同时获得矿物年龄,为当前矽卡岩型矿床相关的关键金属研究提供了更为便捷的方法。  相似文献   

共炮检距二维弹性波地震剖面的偏移方法   总被引：1，自引：0，他引：1  

马在田 《地球物理学报》1995,38(Z1):1-10

在均匀各向同性介质的分界面上入射纵波时，除产生纵波反射Ｐ－Ｐ波外，还会产生转换横波的反射Ｐ－ＳＶ波。同样，当入射波为ＳＶ横波时，在分界面上会同时产生ＳＶ－ＳＶ反射波和ＳＶ－Ｐ反射转换波，对这种二维弹性波地震记录如何进行偏移是正在探讨的问题。为了能够处理实际地震数据，本文提出在共炮检距剖面上进行二维弹性波记录的偏移方法。具体做法是，首先用弹性波方程将两分量的地震记录分解为Ｐ－Ｐ（或ＳＶ－ＳＶ）波和Ｐ－ＳＶ（或ＳＶ－Ｐ）波，然后用我们已导出的适合于处理共炮检距剖面的叠前偏移方法对它们进行处理。用模拟数据进行的试验说明方法正确，效果良好。  相似文献   

Evidence of chromosomal damage in common eiders (Somateria mollissima) from the Baltic Sea     

Matson CW  Franson JC  Hollmén T  Kilpi M  Hario M  Flint PL  Bickham JW 《Marine pollution bulletin》2004,49(11-12):1066-1071

Common eiders nesting in the Baltic Sea are exposed to generally high levels of contaminants including potentially genotoxic polycyclic aromatic hydrocarbons and organochlorines. Blood samples were collected from eiders at eight sites in the Baltic Sea and two sites in the Beaufort Sea. DNA content variation was estimated using the flow cytometric method, and subsequently utilized as a biomarker of genetic damage. We observed no significant differences in genetic damage among populations within either the Baltic or Beaufort Seas. However, eider populations from the Baltic Sea had significantly elevated estimates of genetic damage compared to populations from the Beaufort Sea.  相似文献   

Molecular cloning and mRNA expression of cytochrome P4501A1 and 1A2 in the liver of common minke whales (Balaenoptera acutorostrata)     

Satoko Niimi  Michio X. Watanabe  Eun-Young Kim  Hisato Iwata  Genta Yasunaga  Yoshihiro Fujise  Shinsuke Tanabe 《Marine pollution bulletin》2005,51(8-12):784

This study presents full-length cDNA sequences of CYP1A1 and 1A2, in common minke whale (Balaenoptera acutorostrata) from the North Pacific. Both CYP1A1 and CYP1A2 cDNAs had an open reading frame of 516 amino acid residues, and predicted molecular masses were 58.3 kDa and 58.1 kDa, respectively. The deduced full-length amino acid sequence of CYP1A1 revealed higher identities with those of sheep (86%) and pig (87%), and that of CYP1A2 was most closely related to human (82%) and monkey CYP1A2 (82%) among species from which CYP1A2 has been isolated so far. Differences in certain conserved and functional amino acid residues of CYP1A1 and 1A2 between common minke whale and other mammalian species indicate the possibility of their specific metabolic function. Concentrations of organochlorine compounds (OCs) including PCBs and DDTs analyzed in common minke whale liver showed no significant correlation with hepatic mRNA expression levels of CYP1A1 and CYP1A2, indicating no induction of these enzymes by such OCs.  相似文献   

中国大陆科学钻探100-2000m超高压变质岩普通Pb同位素地球化学初步研究——俯冲陆壳内脱耦的证据   总被引：1，自引：0，他引：1  

董锋李曙光  李秋立刘贻灿 陈福坤 《岩石学报》2006,22(7):1791-1798

本文首次对中国大陆科学钻探工程100～2000m榴辉岩中的绿辉石和片麻岩中的长石进行了普通Pb同位素研究。钻孔上部岩段（0-800m）样品放射成因Pb同位素含量比较高且变化幅度较小（^206Pb／^204Pb=16．81-17．29，^207Pb／^204Pb=15．37-15．45，^208Pb／^204Pb=37．20-37．66），说明其原岩的U／Pb和Th／Pb或者初始Pb同位素比值比较高。钻孔中部岩段（800-1600m）发育有韧性剪切带，相应的Pb同位素比值开始降低且有起伏（^206Pb／^204Pb=16．26-16．72，^207Pb／^204Pb=15．27～15．38，^208Pb／^204Pb=36．73～37．40）、钻孔下部岩段（800～1600m）样品放射成因Ph同位素含量低但变化幅度较小（^206Pb／^204Pb=16.05～16．46，^207Pb／^204Pb：15．22～15.29，^208Pb／^204Pb=36．68～37．48），说明其原岩的U／Pb和Th／Pb或者初始Ph同位素比值比较低。实测数据同模拟数据对比表明，钻孔上、下两岩段样品普通Ph同位素不同一方面是由于继承了原岩初始Pb同位素不同，另一方面是由它们的μ值不同所致。结合氧同位素研究，本文认为800m以上和1600m以下分属上地壳和中地壳．前者是从俯冲大陆岩石圈解耦的上地壳，在大陆岩石圈俯冲过程中，上部岩片同俯冲的大陆岩石圈发生挤离，率先沿着这一个挤离面逆冲折返至浅部。下岩片是随后从俯冲岩石圈解耦的中地壳岩片，并折返至浅部下伏在先期折返的上部岩片之下。考虑到中部岩段（800～1600m）既发育有韧性剪切带又具有异常低^18O峰值（Xiao et al．，2006），挤离面是在地壳内部晚元古代的断裂带及冷水活动通道基础上发育起来的。  相似文献   

Evaluation of two direct immunoassays for rapid detection of petroleum products on marine birds     

Fritcher DL  Mazet JA  Ziccardi MH  Gardner IA 《Marine pollution bulletin》2002,44(5):388-395

To reduce rehabilitation time and improve survival, a practical, objective test is needed to determine if marine birds are contaminated with oil before they enter captivity. The RaPID Assays and EnviroGard immunoassays for detection of polycyclic aromatic hydrocarbons (PAHs) in soil were evaluated for their ability to detect petroleum on feather samples from 30 intermediate fuel oil contaminated and 30 uncontaminated common murres (Uria aalge). Sensitivity, specificity, positive and negative predictive value, precision, and time required to run each assay were determined. The RaPID Assays was 96.7% sensitive and specific, while the EnviroGard assay was 93.3% sensitive, and 90.0% specific. Sensitivity decreased at higher dilutions for both assays. Intra-replicate variation was less than 20%. Our evaluation showed that these immunoassays are rapid and cost-effective methods for detecting oil-contamination on the plumage of seabirds, with the EnviroGard assay being more practical in most oil spill response situations due to ease of use and rapidity of results.  相似文献   

数字图书馆的公共性反思     

黄磊  陈慧 《国土资源信息化》2008,(4):3-5,14

本文在把握数字图书馆的基本特征前提下,运用公共性理论分析研究数字图书馆的公共性,通过分析数字图书馆的公共性特征及影响因素,发现许多非技术性的因素影响数字图书馆的进程,甚至违背了数字图书馆的服务宗旨,理想与现实之间存在着很大差距。  相似文献   

基于共姿态道集的静校正方法          下载免费PDF全文

何登科  彭苏萍  孙亮 《地球物理学报》2018,61(1):258-266

静校正问题是地震勘探的关键问题,直接影响地震勘探精度和准确性.实际地震采集过程中,当在相同接收点位置上不同时间内插拔布设了不同的检波器时,对于目前基于地表一致性理论假设的基准面静校正和剩余静校正,以及非地表一致性剩余静校正都不具备适用条件.为解决这一问题,本文提出了基于共姿态道集的静校正方法,将相同接收点位置上不同时间布设的检波点所接收的地震数据抽成不同的共姿态道集,在共姿态道集内实施地表一致性静校正;当某接收点位置上具有若干个共姿态道集时,该接收点位置上可能会存在多个检波点静校量;炮点静校问题仍然采用地表一致性静校正方法解决.该方法解决了同一接收点位置上不同共姿态道集之间的非地表一致性静校正问题,同时也解决了全区的检波点和炮点的地表一致性静校正问题,在实际数据应用效果明显.  相似文献   

EU marine policy on the move: The tension between fisheries and maritime policy     

L. van Hoof  J. van Tatenhove 《Marine Policy》2009

In the past decade, the European Commission has developed the Marine Strategy Directive and the Maritime Policy. Both policies aim at governing the marine environment; yet the two policies have a differing signature in policy formulation and implementation. From a fisher's perspective these policies present a change in institutional setting; major policy measures no longer descend from the EU Common Fisheries Policy alone, but increasingly are derived from general environmental policy developments. In this paper, the policy arrangement approach is used to analyse the differences between the two maritime policies, and the way in which they can affect fisheries management.  相似文献   

国际海底区域环境保护制度分析与中国实践          下载免费PDF全文

万浏  刘大海  王小华  王春娟 《海洋开发与管理》2022,39(2):11-17

为促进国际海底区域资源开发和环境保护的协调可持续发展,提高我国在相关领域的话语权和执行力,文章系统分析国际海底区域环境保护制度的发展特征及其存在的问题,总结我国对国际海底区域环境保护的实践和展望,并提出对策建议。研究结果表明:国际海底区域环境保护制度经历萌芽、成形、发展和充实4个阶段,发展特征主要包括理念的更新、原则的完善以及义务和责任的明确,然而至今在规章环境保护条款、《联合国海洋法公约》非缔约国的环境保护权责和相关利益平衡等方面仍存在问题;我国从参与制定相关制度和开展国内法探索等方面积极实践国际海底区域环境保护;未来应从制定环境保护标准、探索政策环境和平衡各方利益等方面完善国际海底区域环境保护制度,我国应继续参与相关国际法律制度的制定以及完善国内海洋环境保护制度。  相似文献