Geomorphic constraints on the age of the western Grand Canyon
Geomorphic constraints on the age of the western Grand Canyon
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地貌对西部大峡谷年龄的制约
DOI：
10.1130/ges01131.1
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发表时间：
2015
期刊：
影响因子：
2.5
通讯作者：
K. Whipple
中科院分区：
文献类型：
--
作者：
A. Darling;K. Whipple
对西部大峡谷（WGC）年龄的假设范围从小于6 Ma到大于70 Ma不等。我们研究了地形，地质和可用的侵蚀率在空间和时间上的关系，以限制合理的峡谷切口的历史。有证据表明，Shivwits高原悬崖的侧向退缩在Sanup高原上留下了一个岩性控制的台阶，但Hualapai高原在古生代地层剖面的岩石类型上不加区别地倾斜。一段时间的加速基准面下降在第三纪是牵连的峡谷切入到倾斜的Hualapai高原表面，与较高的侵蚀速率观察到的峡谷比周围的高原一致。河流排水的华拉派高原保留残留的源头部分，平衡了一个较慢的基准面下降率之前，峡谷切口。这些残存的部分现在与大峡谷分开的缺口指示一个短暂的景观。在WGC，由于瓦拉派高原的倾斜，救济生产为1000米。大洗崖和WGC之间的山坡和通道形态的比较提供了一个测试，以区分假设的年龄峡谷切口。数据强烈表明，雕刻的WGC是年轻的比救济生产由于滑动的大洗断层CA。18-12马。因此，地貌数据仅与晚第三纪完全一致，峡谷切口的瞬时切口模型在6 Ma后的整合开始。
Hypotheses for the age of the western Grand Canyon (WGC) range from younger than 6 Ma to older than 70 Ma. We study the relationships among topography, geology, and available erosion rates in space and time to place constraints on plausible canyon incision histories. Evidence suggests that lateral retreat of the Shivwits Plateau escarpment left a lithologically controlled bench on the Sanup Plateau, but the Hualapai Plateau is beveled indiscriminately across rock types of the Paleozoic stratigraphic section. A period of accelerated base-level fall in the Tertiary is implicated by the canyon incised into the beveled Hualapai Plateau surface, consistent with higher erosion rates observed in canyons than on the surrounding plateau. Streams draining the Hualapai Plateau preserve relict headwater segments that were equilibrated with a slower base-level-fall rate before canyon incision. These relict segments are now separated from the Grand Canyon by knickpoints indicative of a transient landscape. Relief production since the beveling of the Hualapai Plateau is ∼1000 m in the WGC. Comparison of hillslope and channel morphologies between the Grand Wash Cliffs and the WGC provides a test to distinguish hypothesized ages of canyon incision. The data strongly suggest that carving of the WGC is younger than relief production due to slip on the Grand Wash fault ca. 18–12 Ma. Thus the geomorphic data are only fully consistent with the late Tertiary, transient incision model of canyon incision beginning at integration after 6 Ma.
影响因子：
18.3
作者：
Karlstrom, Karl E.;Lee, John P.;Shuster, David L.
通讯作者：
Shuster, David L.