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首页> 外文期刊>Ocean & coastal management >Nearshore sedimentation as a record of landuse change and erosion: Jurujuba Sound, Niteroi, SE Brazil
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Nearshore sedimentation as a record of landuse change and erosion: Jurujuba Sound, Niteroi, SE Brazil

机译：记录了土地利用变化和侵蚀的近岸沉积：巴西东南部尼泰罗伊的Jurujuba Sound

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摘要

The Southeast of Brazil has been subject to successive phases of land disturbance since the sixteenth century that has ultimately resulted in widespread urbanisation. This study details mass movements and fluvial erosion triggered by construction and slash and burn cultivation, on steep slopes in a suburb of Niteroi city, following rapid development since it was joined to Rio de Janeiro by a bridge in 1974. The transport of sediment as a result of human impact is traced to near shore deposits within a nearby enclosed bay that has acted as a sediment sink since its formation by Holocene sea level rise. Cores from this bay reveal an initial influx of sediment coinciding with the arrival of European colonists, but the most rapid sedimentation is related to the recent urbanisation of the catchment. This is commonly associated with intense erosion of deeply weathered regolith and soil triggered by mass movements, quarrying and the excavation of level sites for construction. In the coastal region the coarse fraction of the sediment is mainly composed of construction debris, angular quartz, feldspars and rock fragments. Geochemical analyses of a sedimentary core collected in the centre of the bay showed a recent enrichment of metals (Pb, Ni, Cu, Cr, Zn and Mn) over approximately the last forty years. This is also matched by an increase over time in the foraminifera species Ammonia tepida and a decline in the species Buliminella elegantissima. A. tepida is commonly found in restricted and highly polluted environments,whereas, B. elegantissima is more sensitive to environmental deterioration. Pollen analysis shows a gradual decrease in forest since the European settlement and an increase in field vegetation that has accelerated in recent years, together with the introduction of exotic species. In order to understand human impact on near shore sediments, complementary techniques such as geochemical, micropale-ontological and sedimentological are shown to be very important tools in this field of research.
机译：自16世纪以来，巴西东南部一直受到土地干扰的连续影响，最终导致广泛的城市化进程。这项研究详细介绍了尼特罗伊市郊区陡坡上因建筑，砍伐和焚烧耕种而引发的大规模运动和河流侵蚀，自1974年通过桥梁连接到里约热内卢以来，飞速发展。人为影响的结果可追溯到附近的封闭海湾内的近岸沉积物，该区域自全新世海平面上升以来就一直充当沉积物汇。来自该海湾的岩心显示出最初的泥沙涌入与欧洲殖民者的到来相吻合，但最迅速的沉淀与该流域最近的城市化有关。这通常与大规模运动，采石和开挖施工现场引发的深度风化的碎石和土壤的严重侵蚀有关。在沿海地区，沉积物的粗糙部分主要由建筑碎屑，角质石英，长石和岩石碎片组成。对在海湾中心收集的沉积岩心进行的地球化学分析表明，近四十年来，金属（Pb，Ni，Cu，Cr，Zn和Mn）最近富集。随着时间的推移，有孔虫物种氨水龙舌兰的增加和Buliminella Elegantissima物种的减少也与之匹配。棉铃虫通常在受限制的和高度污染的环境中发现，而淡水梭菌对环境恶化更敏感。花粉分析显示，自欧洲定居以来，森林逐渐减少，近几年来，随着外来物种的引入，田间植被的增加加速了。为了了解人类对近岸沉积物的影响，在这一研究领域中，诸如地球化学，微古生物学和沉积学等辅助技术被证明是非常重要的工具。

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  • 来源
    《Ocean & coastal management》 |2013年第6期|31-39|共9页
  • 作者

    Jose Antonio Baptista Neto; Cintia Ferreira Barreto; Maria Augusta Martins da Silva; Bernard J. Smith; John J. Mcallister; Claudia Gutterres Vilela;

  • 作者单位

    Universidade Federal Fluminense, Lagemar Instituto de Ceociencias, Departamento de Geologia, 4° andar, Av. Gal. Milton Tavares de Souza s, Gragoata, Niteroi,RJ CEP 24210 346, Brazil;

    Universidade Federal Fluminense, Lagemar Instituto de Ceociencias, Departamento de Geologia, 4° andar, Av. Gal. Milton Tavares de Souza s, Gragoata, Niteroi,RJ CEP 24210 346, Brazil;

    Universidade Federal Fluminense, Lagemar Instituto de Ceociencias, Departamento de Geologia, 4° andar, Av. Gal. Milton Tavares de Souza s, Gragoata, Niteroi,RJ CEP 24210 346, Brazil;

    School of Geography, The Queen's University, Belfast, UK;

    School of Geography, The Queen's University, Belfast, UK;

    Laboratorio de Analise Micropaleontologica, Departamento de Geologia, Instituto de Geociencias, Universidade Federal do Rio de Janeiro, CCMN, Ilha do Fundao, 21941 916 RJ, Brazil;

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