Eocene initiation of Nile drainage due to East African uplift
Eocene initiation of Nile drainage due to East African uplift
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由于东非隆起，始新世尼罗河开始排水
DOI：
10.1016/j.palaeo.2013.09.014
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
É. Steurbaut
中科院分区：
文献类型：
--
作者：
C. Underwood;C. King;É. Steurbaut
始新世晚期和渐新世早期埃及法尤姆的沉积序列记录了向北流动的尼罗河型非洲水系的逐步发展。新的生物地层测定这些单位允许校准的古地磁记录，结合定年方法，使详细的事件年表进行研究。在大约38和35 Ma之间，沉积体系发生了巨大的变化，大量的碎屑物质被运送到该地区，使下面的碳酸盐台地窒息，并开始了碎屑单元的逐步扩展。沉积物供应的突然变化与东非图尔卡纳地区开始隆起和火山活动相吻合，切断了来自大陆中部的先前存在的东方排水。因此，法尤姆序列记录了中非和东非向北排水的开始，以及现代尼罗河流域的起源。目前的尼罗河路线的发展，与目前的尼罗河谷的切口，是稍晚，并与渐新世中期上升的红海边缘和墨西拿基准面下降。
The Late Eocene and Early Oligocene sedimentary succession in the Fayum, Egypt records the progressive development of northerly flowing Nile-type African drainage. New biostratigraphic dating of these units allows the calibration of the paleomagnetic record, the combination of dating methods enabling a detailed chronology of events to be studied. Between about 38 and 35 Ma there was a dramatic change in sedimentary regime and vast quantities of clastic material were transported into the area, smothering the underlying carbonate platform and initiating a stepwise progradation of clastic units. The sudden change in sediment availability coincides with the beginning of uplift and volcanic activity in the Turkana region of East Africa, cutting off preexisting easterly drainage from the middle of the continent. The Fayum succession therefore records the initiation of northerly drainage of central and eastern Africa, and the origins of the modern Nile watershed. The development of the current route of the Nile, with the incision of the current Nile Valley, was slightly later and related to mid Oligocene uplift of the Red Sea margins and Messinian base level fall.