• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Climate of the past >Mid-late Holocene event registered in organo-siliciclastic sediments of Lagoa Salgada carbonate system, southeast Brazil
【24h】

Mid-late Holocene event registered in organo-siliciclastic sediments of Lagoa Salgada carbonate system, southeast Brazil

机译：巴西东南部Lagoa Salgada碳酸盐系统的有机硅质碎屑沉积中晚全新世事件

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The formation of the Paraiba do Sul river delta plain on the coast of Rio de Janeiro state, Brazil, gave rise to diverse lagoons formed under different sea level regimes and climate variations. Sedimentary core lithology, organic matter geochemistry, and isotopic composition (delta C-13 and delta N-15) were analyzed to interpret the sedimentation of the paleoenvironment of the Lagoa Salgada carbonate system. Different lithofacies reflect variations in the depositional environment. The abundance of silt and clay between 5.8 and 3.7 kyr enhances the interpretation of a transgressive system, which promoted the stagnation of coarse sediment deposition due to coast drowning. Geochemistry data from this period (5.8-3.7 kyr) suggest the dominance of a wet climate with an increase of C-3 plants and a marked dry event between 4.2 and 3.8 kyr. This dryer event also matches with previously published records from around the world, indicating a global event at 4.2 ka. Between 3.8 and 1.5 kyr, Lagoa Salgada was isolated; sand and silt arrived at the system by erosion with the retreat of the ocean and less fluvial drainage. Geochemistry from this moment marks the changes to favorable conditions for microorganisms active in the precipitation of carbonates, forming microbial mats and stromatolites in the drier phase.
机译：巴西里约热内卢州海岸沿岸的Paraiba do Sul河三角洲平原的形成，导致了在不同海平面和气候变化下形成的各种泻湖。分析了沉积岩心岩性，有机质地球化学和同位素组成（δC-13和δN-15），以解释Lagoa Salgada碳酸盐体系的古环境沉积。不同的岩相反映沉积环境的变化。 5.8至3.7吉尔之间的淤泥和粘土含量丰富，增强了对海侵系统的解释，该系统加剧了沿海溺水造成的粗大沉积物淤积的停滞。这一时期（5.8-3.7年）的地球化学数据表明，湿润气候占主导地位，C-3植物数量增加，在4.2至3.8年之间出现了明显的干旱事件。该干燥机事件还与来自世界各地的先前发布的记录相匹配，表明这是全球性事件，发生在4.2 ka。在3.8至1.5吉尔之间，Lagoa Salgada被隔离；沙子和淤泥是由于海洋退缩和河流排水减少而受到侵蚀而到达系统的。从那时起的地球化学标志着对活跃于碳酸盐沉淀，在干燥相中形成微生物垫和叠层石的微生物的有利条件的改变。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号