Drainage integration and sediment dispersal in active continental rifts: A numerical modelling study of the central Italian Apennines
Drainage integration and sediment dispersal in active continental rifts: A numerical modelling study of the central Italian Apennines
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DOI：
10.1111/bre.12289
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发表时间：
2018-07
期刊：
影响因子：
3.2
通讯作者：
A. Geurts;P. Cowie;G. Duclaux;R. Gawthorpe;R. Huismans;V. Pedersen;L. Wedmore
中科院分区：
文献类型：
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作者：
A. Geurts;P. Cowie;G. Duclaux;R. Gawthorpe;R. Huismans;V. Pedersen;L. Wedmore
在地球仪周围的大陆地区，可以观察到在地壳活动伸展期间，水系逐渐整合。这种现象通常被解释为溯源侵蚀，由到外部基准面（例如海岸）的距离控制。然而，驱动整合的机制的结论性现场证据通常是缺乏的，因为排水整合事件通常伴随着强烈的侵蚀。基于对意大利中部亚平宁山脉活跃延伸的数值模拟研究，我们表明溢出机制（盆地溢出和湖泊溢出）更可能是在伸展环境中驱动排水整合的机制，并且沉积物供应与断层边界盆地中的容纳创造之间的平衡至关重要。在该地区，自更新世早期以来湖泊消失以及从内部（内陆）到外部排水（即连接到海岸）的过渡证明了排水系统的整合。使用从亚平宁山脉中部的实地观测，我们约束正常的断层和区域表面隆起内的表面过程模型CASCADE（布劳恩和Sambridge，1997年，盆地研究，9，27），并演示了排水整合的现象，显示它如何导致湖泊逐渐消失，并过渡到一个相互关联的河流运输系统随着时间的推移。我们的模型结果表明，在亚平宁山脉中部，通过区域隆起和断块隆起产生的地形起伏产生了足够的沉积物来填充伸展盆地，使溢出和单个盆地最终成为河流连接。我们讨论了实地观察，支持我们的研究结果，并抛出新的光后，以前发表的解释景观演变在这方面。我们还评估了地形发展，区域沉积物扩散和近海沉积物供应的排水一体化的影响。最后，我们讨论了我们的研究结果的适用性，其他大陆裂谷（包括那些区域隆起是缺席）和瞬态景观演化的重要性，排水整合。
Progressive integration of drainage networks during active crustal extension is observed in continental areas around the globe. This phenomenon is often explained in terms of headward erosion, controlled by the distance to an external base‐level (e.g. the coast). However, conclusive field evidence for the mechanism(s) driving integration is commonly absent as drainage integration events are generally followed by strong erosion. Based on a numerical modelling study of the actively extending central Italian Apennines, we show that overspill mechanisms (basin overfilling and lake overspill) are more likely mechanisms for driving drainage integration in extensional settings and that the balance between sediment supply vs. accommodation creation in fault‐bounded basins is of key importance. In this area drainage integration is evidenced by lake disappearance since the early Pleistocene and the transition from internal (endorheic) to external drainage, i.e. connected to the coast. Using field observations from the central Apennines, we constrain normal faulting and regional surface uplift within the surface process model CASCADE (Braun & Sambridge, 1997, Basin Research, 9, 27) and demonstrate the phenomenon of drainage integration, showing how it leads to the gradual disappearance of lakes and the transition to an interconnected fluvial transport system over time. Our model results show that, in the central Apennines, the relief generated through both regional uplift and fault‐block uplift produces sufficient sediment to fill the extensional basins, enabling overspill and individual basins to eventually become fluvially connected. We discuss field observations that support our findings and throw new light upon previously published interpretations of landscape evolution in this area. We also evaluate the implications of drainage integration for topographic development, regional sediment dispersal and offshore sediment supply. Finally, we discuss the applicability of our results to other continental rifts (including those where regional uplift is absent) and the importance of drainage integration for transient landscape evolution.