• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>South African Journal of Geology: Being the Transaction of the Geological Society of South African: Syndie die Verhandelinge van die Geologiese Vereniging van Suid-Afrika >Hydrological changes in southern Africa over the last 200 Ka as recorded in lake sediments from the Tswaing impact crater
【24h】

Hydrological changes in southern Africa over the last 200 Ka as recorded in lake sediments from the Tswaing impact crater

机译：Tswaing撞击坑的湖底沉积物记录了最近200 Ka南部非洲的水文变化

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

Sediments from Lake Tswaing (25 degrees 24'30" S, 28 degrees 04'59" E) document hydrological changes in southern Africa over the last 200 Ka. Using high-resolution XRF- scanning, basic geochemistry (TIC, TOC, TN), organic petrology and rock-evil pyrolysis, we identify intervals of decreased carbonate precipitation, increased detrital input, decreased salinity and decreased autochthonous (algal and bacterial) organic matter content that represent periods of less stable water column stratification and increased rainfall. Between 200 and 80 Ka BP, these intervals appear to be contemporaneous with local summer insolation maxima, indicating a strong influence of precessional variability (similar to 23 Ka) on African subtropical climate. This influence weakens during the last glacial period (similar to 80 to 10 Ka BP), when humid intervals at 73 to 68 Ka, 54 to 50 Ka, 37 to 35 Ka and 15 to 10 Ka BP are largely out of phase with insolation changes, and presumably reflect southward displacement of the ITCZ (Inter Tropical Convergence Zone) and/or changes in ocean circulation.
机译：吐温湖（南纬25度24'30“，东经28度04'59”）的沉积物记录了最近200 Ka南部非洲的水文变化。使用高分辨率XRF扫描，基本地球化学（TIC，TOC，TN），有机岩石学和岩石邪恶的热解作用，我们确定了碳酸盐沉淀减少，碎屑输入增加，盐分减少和自生（藻类和细菌）有机物减少的时间间隔表示不稳定的水柱分层和降雨增加的时期的含量。在200至80 Ka BP之间，这些间隔似乎与当地夏季的日照最大值同时发生，这表明进动变化（类似于23 Ka）对非洲亚热带气候有很大影响。在最后一个冰川期（类似于80至10 Ka BP），当日照变化导致73至68 Ka，54至50 Ka，37至35 Ka和15至10 Ka BP的湿润时间间隔大大不同时，这种影响减弱，大概反映了ITCZ（热带汇合带）的南移和/或海洋环流的变化。

著录项

相似文献

  • 外文文献
  • 中文文献
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