全球旋回地层学

全球旋回地层学是指在对全球沉积岩进行综合系统研究之基础上，通过估算沉积盆地中源于物源区的沉积物类型和沉积环境条件变化，来预测地层学特征的一种过程一结果模型。其研究内容包括对全球地质演化时期全球海平面变化、全球气候条件、全球构造运动、全球古地理背景、全球沉积环境特征、全球古生物事件及全球矿产形成过程进行动态模拟，强调古气候在地质记录中的意义，注重沉积记录的全球同时性研究；强调各种事件在沉积作用中的意     

碳酸盐岩地层不整合面及孔隙发育

本文的目的是对Ｈｅｄｂｅｒｇ会议有关碳酸盐岩地层不整合面及相关孔隙预测的观点进行阐明和总结，以期抛砖引玉。本文包括岩心、露头、地震、全球海平面曲线、电缆测井、生物地层学、稳定同位素演化趋势、旋回叠置型式、构造及盆地演化模式等在内的许多资料和方法，均可用于查明和／或预测地表不整合面，其中任一方法均有其局限性。对露头或岩心资料进行详细的地层学、沉积学及成岩史分析是查明地表暴露最可靠的方法，尽管已提出了     

A Measurement of Omega from the North American Test Flight of Boomerang

We use the angular power spectrum of the cosmic microwave background, measured during the North American test flight of the Boomerang experiment, to constrain the geometry of the universe. Within the class of cold dark matter models, we find that the overall fractional energy density of the universe Omega is constrained to be 0.85相似文献   

四川省夹江县地质地貌资源现状及旅游可持续开发研究

对四川省夹江县主要地质地貌资源进行了叙述,分析了这些资源对旅游开发的重要意义,提出了开发的构想和保护原生地质地貌环境的建议。     

东海陆架全新统高分辨率层序地层学研究

在高分辨率１４Ｃ测年、岩石、生物、化学、同位素、气候及磁性地层学研究成果基础上,通过不同沉积背景典型钻孔的沉积学分析,运用层序地层学理论,对东海陆架全新统进行了高分辨率层序划分及对比;建立了全新世层序地层格架及海平面变化过程;提出了相应的层序成因模式。研究结果表明,东海陆架全新统相当于一个发育中的六级（１～１０ｋａ）层序,可进一步划分为３个七级（０．１～１ｋａ）层序和若干个更次级层序。代表１个六级或３个七级周期相对海平面变化过程中叠加有若干更次级的海平面波动,它们与地球旋回谱系中的太阳带、历法带密切相关。七级层序具有与三级层序相近的内部构型和成因格架。在东海陆架全新世沉积演化过程中,长江三角州至少有３次不同程度地越过东海陆架进入冲绳海槽,并滞留有至少３层海侵改造“残积砂”沉积。在东海陆架全新世海平面变化期间,最大海平面时期为约距今６～５ｋａ,大致高于现今海平面２～４ｍ,最低海平面在距今１０ｋａ左右,大约低于现今海平面１３０ｍ。目前,由于温室效应的影响,海平面仍呈小幅度波浪式上升。事实证明,层序地层学不仅丰富了现代海洋沉积学的内容,而且解决了许多海洋沉积学未能解决的问题。     

等值代换--巧测E-601B型蒸发器的蒸发量

广西各基准站和基本站从1997年1月1日起,已正式使用E-601B型蒸发器,其基本原理为:若当日中有较大的降水而使蒸发桶里的水溢进溢流桶时,按规范的要求,要用500ml专用量杯测量溢流量,再把所量得的总读数值除以300,得到的值与当日测到的水面高度相加作为余量,然后按公式:蒸发量=原量-余量,这样就可以测量出当日的蒸发量.诚然,若当日水量不很大,溢流桶里的水量不很多时,用此方法就不觉得有什么特别不便之处.若当日有较大降水,以致溢流桶内的水量很多时,仍按规范用专用量杯量之,少则要量七八次,多则要量十几二十次,甚至更多次,才能测完溢流量.这样不但让观测员操作烦赘、费时,并且有时读数多也容易混乱,不便记易,容易造成人为的误差,从而影响了记录值.     

汶川地震遗迹旅游资源分类及特色评价

汶川地震造就了大量地震遗迹景观, 成为了地震科学研究及旅游开发活动的重要资源基础。对地震遗迹景观分类没有形成统一的认识, 广义与狭义视角并存, 两分法与一分法并现。充分考虑地震遗迹旅游资源成因及景观特征, 强调地震活动对地震遗迹旅游资源成景过程的影响及响应, 将其分为2个景观型, 4个景观域、6个景观段、13个景观元及若干典型地震遗迹景观; 重点介绍了北川县城地震遗址、都汶公路百花大桥、都江堰虹口深溪沟地表破裂、北川县唐家山堰塞湖、北川县城城西滑坡遗迹等典型地震遗迹旅游资源; 提炼出“国际意义的地质科学研究对象、全球吸引力的典型地震遗迹、国际品质的地震遗迹旅游资源开发条件、世界级震撼力的地震灾难性事件”四大特色。研究结论有利于地震遗迹旅游资源的保护及震区旅游恢复重建, 为高烈度山区地震专项旅游产品开发提供科学依据。     

Natural attenuation, biostimulation and bioaugmentation on biodegradation of polycyclic aromatic hydrocarbons (PAHs) in mangrove sediments

The biodegradability of a mixture of PAHs, namely fluorene (Fl), phenanthrene (Phe) and pyrene (Pyr), in mangrove sediment slurry was investigated. At the end of week 4, natural attenuation based on the presence of autochthonous microorganisms degraded more than 99% Fl and Phe but only around 30% of Pyr were degraded. Biostimulation with addition of mineral salt medium degraded over 97% of all three PAHs, showing that nutrient amendment could enhance Pyr degradation. Bioaugmentation with inoculation of a PAH-degrading bacterial consortium enriched from mangrove sediments did not show any promotion effect and the degradation percentages of three PAHs were similar to that by natural attenuation. Some inhibitory effect was observed in bioaugmentation treatment in week 1 with only 50% Fl and 70% Phe degraded. These results indicate that autochthonous microbes may interact and even compete with the enriched consortium during PAH biodegradation. Natural attenuation appeared to be the most appropriate way to remedy Fl- and Phe-contaminated mangrove sediments while biostimulation was more capable to degrade Pyr-contaminated sediments. The study also shows that although a large portion of the added PAHs (more than 95%) was adsorbed onto the sediments at the beginning of the experiment, most PAHs were degraded in 4 weeks, suggesting that the degraders could utilize the adsorbed PAHs efficiently.     

Water quality and presence of pesticides in a tropical coastal wetland in southern Mexico

The water quality of the Pozuelos-Murillo lagoon system in southern Mexico was evaluated during three periods between March and October 2002, with particular emphasis on the detection of organochlorine and organophosphorous pesticide residues in water and sediments. Physicochemical and microbiological parameters of water were also measured and integrated in a water quality index (WQI). Multivariate analysis was used to regionalise the lagoon system as a function of the behaviour of all measured parameters. Solid phase micro-extraction followed by gas chromatography (SPME-GC) was used for pesticide analysis. The concentration of phosphorous was found to be higher than that of nitrogenous compounds. This, besides a deficiency in dissolved oxygen and a high organic matter concentration (as COD), reflects eutrophication processes in some areas of the system. Measured levels of faecal coliforms and oils and greases were above the limits established by Mexican law and comparable to the concentrations reported for other highly polluted systems in Mexico. Residues of DDD (2.0 microg L(-1)) in water and DDE (247 ng g(-1)) and endosulfan I (814 ng g(-1)) sediments were detected by SPME-GC. The spatial distribution of these contaminants implies major potential risks because the most polluted sites were found to be those with the highest fishing activity. Although in general the WQI is on acceptable levels (65-80%), some contamination problems are evident.