Controls on bedrock channel incision along nahal paran, Israel
Controls on bedrock channel incision along nahal paran, Israel
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以色列巴兰河沿线基岩河道切开控制
DOI：
10.1002/esp.3290190102
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发表时间：
1994
影响因子：
3.3
通讯作者：
V. Baker
中科院分区：
文献类型：
--
作者：
E. Wohl;N. Greenbaum;A. Schick;V. Baker
纳哈勒巴兰排水3600平方公里的埃及西奈半岛和以色列的内盖夫沙漠。大部分河道是冲积的，但在盆地下部的晚白垩世燧石和白云岩中切割出一个10·5 km长的峡谷。在峡谷内保存的静水沉积物和古阶段指示器记录了至少350年内约10次200至2500 m3 s-1的洪水。洪水水力学的步回水模拟表明，沿峡谷长度的每单位面积沿着流功率的极端变化，以及相关的能量消耗和泥沙输运的变化。这些变化反映了通道横截面形态。流功率的最大值发生在沿着研究河段的下半部分，与三个明显的断点和一个内部通道。这些特征的位置反映了沿通道沿着厚的抗燧石层的暴露。存在几个类似的，但埋藏和不活跃的，knickpoints沿着上的研究达到表明，最活跃的通道切口的轨迹已随着时间的推移，可能是在响应基准面变化与构造活动沿着死海裂谷。因此，沿纳哈尔帕兰峡谷的河道下切沿着的速率和方式受岩性变化和构造抬升的控制，因为它们影响河道形态和坡度，进而影响水力学和沉积物输运。
Nahal Paran drains 3600 km2 of Egypt's Sinai peninsula and Israel's Negev Desert. Much of the channel is alluvial, but a canyon 10·5 km long has been incised into Late Cretaceous chert and dolomite in the lower portion of the basin. Slackwater deposits and paleostage indicators preserved within the canyon record approximately 10 floods of 200 to 2500 m3 s−1 over a period of at least 350 years. Step-backwater simulations of flood-flow hydraulics indicate extreme variations in stream power per unit area along the length of the canyon, and associated variability in energy expenditure and sediment transport. These variations reflect channel cross-sectional morphology. The greatest values of stream power occur along the lower half of the study reach, in association with three pronounced knickpoints and an inner channel. The locations of these features reflect the exposure of thick, resistant chert layers along the channel. The presence of several similar, but buried and inactive, knickpoints along the upper study reach indicates that the locus of most active channel incision has shifted with time, probably in response to baselevel changes associated with tectonic activity along the Dead Sea Rift. Thus, the rate and manner of channel incision along the canyon of Nahal Paran are controlled by lithologic variability and tectonic uplift as they influence channel morphology and gradient, which in turn influence hydraulics and sediment transport.