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Incision History of the Three Gorges, Yangtze River Constrained From Inversion of River Profiles and Low‐Temperature Thermochronological Data
Journal of Geophysical Research: Earth Surface ( IF 3.5 ) Pub Date : 2021-02-01 , DOI: 10.1029/2020jf005767
Ruohong Jiao 1 , Rong Yang 2 , Xiaoping Yuan 3
Affiliation  

We reconstruct the incision history of bedrock rivers based on inverse modeling of the long profile of a river channel and the low‐temperature thermochronological data. Our approach first infers an erodibility‐dependent incision history through a linear inversion of the channel elevations of the river. Then to calibrate the reconstructed incision history in the geological timescale, we constrain the erosional efficiency by optimizing the erosion process of the river catchment using a Bayesian analysis, such that the exhumation and cooling paths of bedrocks in the catchment conform to the observed thermochronological ages. We apply this approach to estimate the incision history of the Three Gorges, Yangtze River in East Asia. We modeled the incision histories of three tributaries on the mainstem Yangtze River near the eastern end of the Three Gorges area, assuming that the gorge incision was driven by increased upstream drainage area of the Upper Yangtze (Scenario 1) or local tectonic uplift (Scenario 2). The results of both scenarios suggest an early Miocene onset of the incision of Three Gorges, that is, 18 ± 6 Ma or 21 ± 4 Ma, respectively. During the Pliocene, our models suggest a significant decrease in the gorge incision rate. By comparing the estimated gorge incision history to the late Cenozoic denudation of the eastern Tibetan Plateau and the regional climate change, we suggest that the incision of the Three Gorges has been heavily affected by the development of the Upper Yangtze River and the East Asian monsoon.

中文翻译:

长江断面逆转和低温热年代学资料制约的长江三峡切入历史

我们基于河道长剖面和低温热年代学数据的逆向建模,重建了基岩河流的切割历史。我们的方法首先通过对河道高程进行线性反演来推断与侵蚀性有关的切口历史。然后,为了校准地质时标中的重建切口历史,我们使用贝叶斯分析通过优化河流集水区的侵蚀过程来限制侵蚀效率,以使流域中基岩的发掘和冷却路径符合观测到的热年代年龄。我们采用这种方法来估计东亚长江三峡的切开历史。我们在三峡地区东端附近的长江干流的三个支流的切开历史模型中,假设峡谷切开是由上扬子上游的排水面积增加(方案1)或局部构造隆升驱动的(方案2) )。两种情况的结果都表明三个峡谷的中新世开始较早,分别为18±6 Ma或21±4 Ma。在上新世期间,我们的模型表明峡谷切开率显着降低。通过将估计的峡谷切开历史与青藏高原东部新生代晚期剥蚀和区域气候变化进行比较,我们认为三峡切开受到长江上游和东亚季风的发展的严重影响。假设峡谷切口是由上扬子上游的排水面积增加(方案1)或局部构造隆升(方案2)驱动的。两种情况的结果都表明三个峡谷的中新世开始较早,分别为18±6 Ma或21±4 Ma。在上新世期间,我们的模型表明峡谷切开率显着降低。通过将估计的峡谷切开历史与青藏高原东部新生代晚期剥蚀和区域气候变化进行比较,我们认为三峡切开受到长江上游和东亚季风的发展的严重影响。假设峡谷切口是由上扬子上游的排水面积增加(方案1)或局部构造隆升(方案2)驱动的。两种情况的结果都表明三个峡谷的中新世开始较早,分别为18±6 Ma或21±4 Ma。在上新世期间,我们的模型表明峡谷切开率显着降低。通过将估计的峡谷切开历史与青藏高原东部新生代晚期剥蚀和区域气候变化进行比较,我们认为三峡切开受到长江上游和东亚季风的发展的严重影响。两种情况的结果都表明三个峡谷的中新世开始较早,分别为18±6 Ma或21±4 Ma。在上新世期间,我们的模型表明峡谷切开率显着降低。通过将估计的峡谷切开历史与青藏高原东部新生代晚期剥蚀和区域气候变化进行比较,我们认为三峡切开受到长江上游和东亚季风的发展的严重影响。两种情况的结果都表明三个峡谷的中新世开始较早,分别为18±6 Ma或21±4 Ma。在上新世期间,我们的模型表明峡谷切开率显着降低。通过将估计的峡谷切开历史与青藏高原东部新生代晚期剥蚀和区域气候变化进行比较,我们认为三峡切开受到长江上游和东亚季风的发展的严重影响。
更新日期:2021-03-16
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