Genesis of anhydrite in hydrothermally altered basalt from the East Pacific Rise near 13°N     

CHEN Shuai  WANG Xiaoyuan  YIN Xuebo  ZHANG Guoliang 《海洋学报(英文版)》2013,32(2):12-17

This study reports the occurrence of anhydrite in hydrothermally altered pillow basalt (12°50.55′N, 103°57.62′W, water depth 2 480 m), which may have been produced in the basalt during seawater-basalt interaction in the laboratory. The existence of anhydrite in the altered basalt indicates extensive hightemperature hydrothermal alteration at the surface of seafloor pillow basalt. Microprobe analysis shows significant chemical zoning in the hydrothermally altered pillow basalt, in which Ca, Si and Al contents decrease and P, Fe, Mn, Cr and S contents increase from fresh basalt to altered basalt. The negative correlation between Rb-Sr and Li-Sr, and negative correlation between Li-Ca and Rb-Ca in the high-temperature vent fluids show that these fluids underwent anhydrite precipitation before fluid jetting due to mixing with seawater in the sub-seafloor. Based on these observations, we show that not all Ca in the anhydrite comes from basalt in the reaction zone, and that the basalts on the seafloor or in the upflow zone may also provide Ca for anhydrite.  相似文献   

Nitrogen uptake dynamics of a persistent cyanobacterium Cyanothece sp. bloom in Lake St Lucia,South Africa     

《African Journal of Marine Science》2013,35(2):155-161

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Supernovae interacting with a circumstellar medium: New observations with X‐shooter     

A. Pastorello  S. Benetti  F. Bufano  E. Kankare  S. Mattila  M. Turatto  G. Cupani 《Astronomische Nachrichten》2011,332(3):266-271

In this article we present new data of a sample of core‐collapse supernovae showing unequivocal evidences of interaction between their ejecta and pre‐existing circumstellar matter (CSM). This CSM was produced by the progenitor star through major mass loss episodes during the final stages of its life. The study of the properties of the SN ejecta and the circumstellar environment are crucial to unveil the nature of the progenitors producing interacting supernovae. In this context, the instrumental combination Very Large Telescope (VLT) plus X‐shooter provides spectra covering simultaneously the optical and near‐infrared domains, and with adequate resolution to constrain the main properties of the supernova and its environment, including its chemical composition, the ejection velocity and the distribution of the emitting gas (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

土壤和围岩地球化学组成及气候对洞穴滴水水化学的影响——以湖北清江和尚洞为例   总被引：4，自引：0，他引：4  

王明达  胡超涌  周炼  朱昌杰 《地质科技情报》2010,29(3)

大气降水渗入土壤,穿过围岩,将气候与地表环境信息导入洞穴滴水,最终被洞穴沉积物所记录,因而研究土壤、围岩与洞穴滴水的地球化学组成及3者之间的联系对了解气候和环境信号的传递以及石笋古环境信息的正确解译十分重要。通过对比清江地区和尚洞上覆土壤、围岩与滴水的元素及锶同位素N(87Sr)/N(86Sr)地球化学组成特征,进而调查土壤和围岩对洞穴滴水水化学的影响。结果表明:滴水的n(Mg)/n(Ca)、n(Ba)/n(Ca)、n(Sr)/n(Ca)及N87Sr)/N(86Sr)介于土壤和围岩之间,说明滴水物质组成来自土壤和围岩的混合;滴水的n(S)/n(Ca)大于土壤和围岩,说明有第三端元的混入,可能是大气硫沉降的结果。通过模型计算可知,土壤和围岩对和尚洞滴水各元素组成的贡献并不相同,贡献的相对大小不仅与元素本身的地球化学性质有关,而且随气候和环境而发生变化。  相似文献   

北京市生活垃圾产生量预测方法的比较分析   总被引：1，自引：0，他引：1  

刘晓宇  周素霞  夏训峰  席北斗  张颖  纪丹凤  顾雨  冯雪华 《地质灾害与环境保护》2010,21(2):68-70

依据北京市1991~2006年的生活垃圾产生量及其相关影响因子,运用多元线性回归法、灰色模型、BP神经网络3种预测模型进行了模拟,并预测了北京市2007年和2010年的垃圾产生量,通过绝对百分误差(MAPE)等指标比较了预测精确度。结果表明,BP神经网络综合考虑了各种因素的影响,较前两者的拟合和预测精度高。  相似文献   

地震沉积学研究方法评析   总被引：7，自引：0，他引：7       下载免费PDF全文

陈旭  陈红汉  董玉文  蔡李梅 《沉积与特提斯地质》2010,30(1):54-60

笔者在前人研究的基础上,对地震沉积学的理论、研究现状和发展趋势进行了较为全面的阐述,并对地震沉积学的关键技术问题进行了较深入的讨论。地层切片是应用沿两个等时界面间等比例内插出的一系列层面进行沉积体系和沉积相平面展布研究的技术;90°相位转换(调整)使地震相位具有了岩性地层意义,可以用于高频层序地层的解释;基于不同频率地震资料反映的地质信息的不同,采用分频段解释的方法,可使地震结果的解释更加明确。由于受地震分辨率和解释手段的限制,地震沉积学的研究目前还存在诸多问题,但是作为一门新兴学科,它已成为隐蔽油气藏勘探的一个突破口。  相似文献   

塔河油田下古生界溶洞充填巨晶方解石流体来源分析     

李开开  蔡春芳  蔡镠璐  姜磊 《地质科学》2010,45(2)

塔河油田溶洞巨晶方解石充填物的微量元素、碳、氧、锶同位素地球化学和流体包裹体的对比研究表明,不同井位巨晶方解石可能来源于不同的流体体系。T417井和S76井鹰山组、T904井一间房组及TS1井丘里塔格组溶洞巨晶方解石样品具有富U、高V/Cr特征,且均一温度主要分布于148.9～169.9℃,相对围岩所经历最高温度约20℃,反映为还原性的热液流体体系,该流体具有高~(87)Sr/~(86)Sr及低δ~(18)O的特征。T904井良里塔格组巨晶方解石具有贫U、低V/Cr及均一温度较低的特征(75～81℃),反映为富氧低温流体体系,结合样品的高~(87)Sr/~(86)Sr及低δ~(18)O特征,可以推测该低温流体可能为大气水来源。热液流体与大气淡水的运移受断层、裂缝和不整合面等因素控制,从而使得不同井位、层位的巨晶方解石沉淀时具有不同的流体成分与温度特征。  相似文献   

The demographics of energy and mobility poverty: Assessing equity and justice in Ireland,Mexico, and the United Arab Emirates     

《Global Environmental Change》2023

Energy and mobility poverty limits people’s choices and opportunities and negatively impinges upon structural economic and social welfare patterns. It also hampers the ability of planners to implement more equitable and just decarbonization pathways. Research has revealed that climate policies have imposed a financial burden on low-income and other vulnerable groups by increasing food and energy prices, leading as well to global inequality. Similarly, researchers have warned that in developing countries, emission mitigation policies could increase poverty rates and even frustrate progress towards universal access to clean energy. This research explores whether low-income social groups experience a 'double energy vulnerability', a situation that simultaneously positions people at heightened risk of transport and energy poverty. We investigate this 'double vulnerability' through original data collection via three nationally representative surveys of Mexico (N = 1,205), the United Arab Emirates (N = 1,141), Ireland and Northern Ireland (N = 1,860). We draw from this original data to elaborate on the sociodemographic attributes, expenditure and behaviour emerging from energy and transport use, focusing on themes such as equity, behaviour and vulnerability. We propose energy and transport poverty indexes that allow us to summarize the key contributing factors to energy and transport poverty in the countries studied and uncover a strong correlation between these two salient forms of poverty. Our results suggest that energy and transport poverty are common issues regardless of the very different national, and even sub-national, contexts. We conclude that energy and transport poverty requires target policy interventions suitable for all segments of society, thus enabling contextually-tailored, just energy transitions.  相似文献   

IPCC emission scenarios: How did critiques affect their quality and relevance 1990–2022?     

《Global Environmental Change》2022

Long-term global emission scenarios enable the analysis of future climate change, impacts, and response strategies by providing insight into possible future developments and linking these different climate research elements. Such scenarios play a crucial role in the climate change literature informing the Intergovernmental Panel on Climate Change’s (IPCC) Assessment Reports (ARs) and support policymakers. This article reviews the evolution of emission scenarios, since 1990, by focusing on scenario critiques and responses as published in the literature. We focus on the issues raised in the critiques and the possible impact on scenario development. The critique (280) focuses on four areas: 1) key scenario assumptions (40%), 2) the emissions range covered by the scenarios and missing scenarios (25%), 3) methodological issues (24%), and 4) the policy relevance and handling of uncertainty (11%). Scenario critiques have become increasingly influential since 2000. Some areas of critique have decreased or become less prominent (probability, development process, convergence assumptions, and economic metrics). Other areas have become more dominant over time (e.g., policy relevance & implications of scenarios, transparency, Negative Emissions Technologies (NETs) assumptions, missing scenarios). Several changes have been made in developing scenarios and their content that respond to the critique.  相似文献   

不同岩性盐湖沉积物中挥发性有机质的特征          下载免费PDF全文

卢晓航  韩凤清  易磊  马喆  张光武  陈富洪 《盐湖研究》2021,29(1):18-24

通过不同岩性盐湖沉积物中C/N值,确定其有机质的来源均为藻类,然后采用气相色谱—离子迁移谱(GC-IMS)联用技术对不同岩性盐湖沉积物中的挥发性有机质进行了研究.结果显示,不同岩性沉积物的挥发性有机质虽然来源相同,但是其种类和含量存在显著差异.在砂岩沉积物中,检测出16种挥发性有机质,而石盐中共检测出30种挥发性有机质...  相似文献