Delineation of the 85°E ridge and its structure in the Mahanadi Offshore Basin,Eastern Continental Margin of India (ECMI), from seismic reflection imaging

The passive Eastern Continental Margin of India (ECMI) evolved during the break up of India and East Antarctica in the Early Cretaceous. The 85°E ridge is a prominent linear aseismic feature extending from the Afanasy Nikitin Seamounts northward to the Mahanadi basin along the ECMI. Earlier workers have interpreted the ridge to be a prominent hot spot trail. In the absence of conclusive data, the extension of the ridge towards its northern extremity below the thick Bengal Fan sediments was a matter of postulation. In the present study, interpretation of high resolution 2-D reflection data from the Mahanadi Offshore Basin, located in the northern part of the ridge, unequivocally indicates continuation of the ridge across the continent–ocean boundary into the slope and shelf tracts of the ECMI. Its morphology and internal architecture suggest a volcanic plume related origin that can be correlated with the activity of the Kerguelen hot spot in the nascent Indian Ocean. In the continental region, the plume related volcanic activity appears to have obliterated all seismic features typical of continental crust. The deeper oceanic crust, over which the hot spot plume erupted, shows the presence of linear NS aligned basement highs, corresponding with the ridge, underlain by a depressed Moho discontinuity. In the deep oceanic basin, the ridge influences the sediment dispersal pattern from the Early Cretaceous (?)/early part of Late Cretaceous times till the end of Oligocene, which is an important aspect for understanding the hydrocarbon potential of the basin.     

Scientific advice in integrated ocean management: The process towards the Barents Sea plan

It is widely held that integrated management of ocean areas needs to be based on integrated scientific advice. Such advice crosses disciplinary and traditional sector boundaries. This paper aims to provide insight into the role of science and scientific knowledge in a process towards integrated ocean management. It does so by exploring the organization of the process towards the integrated management plan for the Barents Sea-Lofoten area in Norway. It sheds light on the complexity of management questions in a context characterized by uncertainty and political controversy, largely concerning petroleum activity. Scientists were asked to provide a dynamic view on these issues and have delivered important material that furthers the task of policy development. However, there is a persisting lack of understanding about the consequences of human impact on the ecosystem. The paper finishes by pointing at the need for a larger societal discussion on what activities we consider appropriate, considering the limits of science to provide the knowledge base for questions that transcend the environmental domain.     

Methylmercury production in sediments of Chesapeake Bay and the mid-Atlantic continental margin

Methylmercury (MeHg) concentration and production rates were studied in bottom sediments along the mainstem of Chesapeake Bay and on the adjoining continental shelf and slope. Our objectives were to 1) observe spatial and temporal changes in total mercury (HgT) and MeHg concentrations in the mid-Atlantic coastal region, 2) investigate biogeochemical factors that affect MeHg production, and 3) examine the potential of these sediments as sources of MeHg to coastal and open waters. Estuarine, shelf and slope sediments contained on average 0.5 to 1.5% Hg as MeHg (% MeHg), which increased significantly with salinity across our study site, with weak seasonal trends. Methylation rate constants (k_meth), estimated using enriched stable mercury isotope spikes to intact cores, showed a similar, but weaker, salinity trend, but strong seasonality, and was highly correlated with % MeHg. Together, these patterns suggest that some fraction of MeHg is preserved thru seasons, as found by others [Orihel, D.M., Paterson, M.J., Blanchfield, P.J., Bodaly, R.A., Gilmour, C.C., Hintelmann, H., 2008. Temporal changes in the distribution, methylation, and bioaccumulation of newly deposited mercury in an aquatic ecosystem. Environmental Pollution 154, 77] Similar to other ecosystems, methylation was most favored in sediment depth horizons where sulfate was available, but sulfide concentrations were low (between 0.1 and 10 μM). MeHg production was maximal at the sediment surface in the organic sediments of the upper and mid Bay where oxygen penetration was small, but was found at increasingly deeper depths, and across a wider vertical range, as salinity increased, where oxygen penetration was deeper. Vertical trends in MeHg production mirrored the deeper, vertically expanded redox boundary layers in these offshore sediments. The organic content of the sediments had a strong impact on the sediment:water partitioning of Hg, and therefore, on methylation rates. However, the HgT distribution coefficient (K_D) normalized to organic matter varied by more than an order of magnitude across the study area, suggesting an important role of organic matter quality in Hg sequestration. We hypothesize that the lower sulfur content organic matter of shelf and slope sediments has a lower binding capacity for Hg resulting in higher MeHg production, relative to sediments in the estuary. Substantially higher MeHg concentrations in pore water relative to the water column indicate all sites are sources of MeHg to the water column throughout the seasons studied. Calculated diffusional fluxes for MeHg averaged  1 pmol m^− 2 day^− 1. It is likely that the total MeHg flux in sediments of the lower Bay and continental margin are significantly higher than their estimated diffusive fluxes due to enhanced MeHg mobilization by biological and/or physical processes. Our flux estimates across the full salinity gradient of Chesapeake Bay and its adjacent slope and shelf strongly suggest that the flux from coastal sediments is of the same order as other sources and contributes substantially to the coastal MeHg budget.     

新亚欧大陆桥(河南段)经济带地下水资源形势的研究

新亚欧大陆桥,是又一条连接亚欧大陆的“黄金通道”。陆桥的开通,给河南城市群的崛起和城乡产业经济的发展带来了契机。作为经济可持续发展限制因素之一的地下水资源,在陆桥（河南段）经济带范围内,能否满足沿线经济对地下水的需求？研究结论是：地下水形势不容乐观,潜力尚有８７×１０８ｍ３／ａ,同时还存在超采量３８８×１０８ｍ３／ａ,城乡开发地下水强度不一,已引发多种环境地质问题,对陆桥（河南段）经济带的发展构成了严重威胁。为缓和陆桥（河南段）沿线用水矛盾,必须遵循“因地制宜,量水为出,适度开发,统一规划”的原则,在开源、节流、管理上做好用水文章,充分发挥地下水资源的整体效益,实现陆桥（河南段）经济带地下水的可持续开发利用。     

藏北尼玛地区白垩纪岩浆岩对班公湖-怒江缝合带演化的制约

班公湖-怒江缝合带及其两侧广泛分布白垩纪岩浆岩,这些岩浆活动记录了班公湖-怒江特提斯洋俯冲至闭合以及拉萨-羌塘板块碰撞过程.为了约束该缝合带在早-晚白垩世的演化过程,本文对缝合带中段尼玛地区花岗岩进行岩相学、地球化学、锆石年代学和Hf同位素研究.尼玛北部虾别错花岗岩侵入到中生代地层中,发育石英闪长质包体.锆石U-Pb定...     

盘锦湿地生态系统野外观测站概况

重点介绍了盘锦湿地生态系统野外观测站建立的背景、研究定位与研究方向,主要观测场及观测仪器设备,已有基础数据积累和科研任务等。在此基础上,提出了未来盘锦站应在建设目标、人才队伍建设及规范管理方面的重点工作,为将研究站建设成为生态气象监测示范与技术支持基地、研制生态气象业务评估方法与模型的平台、生态气象业务人才培养基地以及作为地球系统科学前沿研究的孵化器,最终成为生态学和资源、环境科学等相关学科的发展提供野外试验和研究平台提供保障。     

Knowledge integration in sustainability governance through science-based actor networks

Understanding how science, technology and innovation can best help to accelerate progress in achieving sustainable development remains a grand challenge for researchers and practitioners. In the context of the global consultation process for preparing a post-2015 Sustainable Development Agenda, various science-based actor networks have emerged, aiming to translate research into political decision-making and to inform transformations towards sustainability. Over the last years, these networks seem to have taken an ever-growing role in structuring the science-policy interface in global sustainability governance. The question arises, however, how they understand and organize ‘scientific knowledge integration’ in sustainability politics.This study offers a structured comparison of twelve global science-based actor networks engaged in the implementation of the Sustainable Development Goals. It shows that these networks use two types of strategies to foster scientific knowledge integration in sustainability governance. A new framework emerges, in which each strategy corresponds to two main approaches of scientific knowledge integration: The entrepreneurial strategy generally seeks to advance advice-oriented and solution-oriented knowledge processes, while assessment-oriented and learning-oriented processes in scientific knowledge integration are mainly promoted through a mediating strategy.     

Continental size,eustasy and sediment yield

Sediment yield from modern continental blocks is a function of the area (dissolved load) and hypsometry (mechanical load) of the blocks. Hypsographic curves for modern continental blocks show that the change in the percentage area flooded for any change in eustatic sea level depends on the size of the block and the absolute sea level. This allows predictions of changes in sediment yield around different sized blocks for any given eustatic change. The range in size of continental blocks is such that, for any given sea level change, the blocks will show different percentage changes in yield. Data from modern continental blocks are compared with theoretical results. Assuming that the rules governing modern hypsometries applied in the past, and a constant volume of continental crust, it is possible to estimate the hypsographic curves of former continental blocks. The implications of suggested past continental configurations and sea levels for sediment yield are discussed.     

阿德朗达克-西魁北克地震带地壳三维速度结构成像

根据在阿德朗达克-西魁北克地震带及其邻近地区的59台短周期数字地震仪记录的直达P波走时观测值,用地震层析成像方法反演了该地区地壳三维速度结构.结果表明,地壳上层（0-5km）在阿德朗达克穹隆山的中南部地区出现正速度异常;第二层（5-10km）及第三层（10-15km）的速度横向变化较小,介质相对比较均匀;第四层（15-25km）出现显著的速度异常,一个是位于地震带中部的正速度异常（+4％）,它与布格重力正异常一致;另一个是位于阿德朗达克穹隆山下的负速度异常（-4％）.结合已有的地质及地球物理资料进行对比,可以认为阿德朗达克是一个正在发展的穹隆上升山,但其热源前锋尚未到达地面的大陆热点.     

冀东陆壳结构的岩石学模型

冀东地区的古老变质岩系是一个出露的大陆地壳断面。根据变质岩系的变质相、亚相的研究和地质温压计计算的结果推定的深度,并结合地球物理测深资料,以及笔者测定和前人的岩石高压下波速实验资料提出了本区大陆地壳结构的岩石学模型。下地壳由麻粒岩相岩石组成,上部为角闪石麻粒岩亚相的中性成分的麻粒岩,下部为辉石麻粒岩亚相的基性成分的麻粒岩构成,底部夹有透镜状蛇纹石化橄榄岩以及紫苏花岗岩。中地壳主要由高角闪岩相的中性-中酸性成分的片麻岩、片岩构成,顶部为低角闪岩相的片麻岩、片岩,广泛发育英云闪长岩和花岗闪长岩岩体,含隙间高温流体相(fluid phase),形成高导-低速层。上地壳主要为绿片岩相(部分低角闪岩相)的板岩、千枚岩、片岩、变粒岩以及花岗岩组成,顶部为沉积盖层