Investigating the autogenic process response to allogenic forcing: Experimental geomorphology and stratigraphy
Investigating the autogenic process response to allogenic forcing: Experimental geomorphology and stratigraphy
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研究自生过程对同种异体强迫的响应：实验地貌学和地层学
DOI：
10.1002/9781118920435.ch5
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发表时间：
2014
期刊：
影响因子：
--
通讯作者：
D. Mohrig
中科院分区：
文献类型：
--
作者：
Wonsuck Kim;A. Petter;K. Straub;D. Mohrig
将保存下来的环境（异源）强迫信号与内部生成（自生）过程的信号解耦是理解沉积记录中保存的地球表面演化的核心。区分地层记录中的同源与自生特征的一个主要障碍是缺乏对自生过程及其与同源强迫的相互作用的定量理解。利用移动的沉积物和水进行的物理实验通过动态的自组织河流系统来构建地形。从而为研究受控边界条件下的自生过程（如沉积物供给和构造）提供了机会。本文介绍了一套水槽实验，用于定量研究1）与河道和面流之间的河流格局变化相关的三角洲顶面沉积物的自循环储存和释放，以及2）由外部强迫（例如海平面变化和构造）驱动的河流自循环行为的变化。在无外力作用的实验中所观察到的自生过程的时间尺度和事件尺度，提供了对自生过程的一阶定量解释。通过基准面变化和侧向地面倾斜的自生过程的频率的变化提供了一个新的视角耦合的地层发育的异体和自生控制。本文介绍了检验外源强迫对自生过程影响的耦合实验：一个实验是在恒定的外源强迫下进行的，另一个实验是在周期性变化的外源控制下进行的。本文提供了1）河流自生过程的定量测量和归因于他生与自生控制的循环地层的彻底比较，2）对河流自生过程的未来实验研究的建议，这将提高我们解释沉积记录中的环境变化和内部动力学的混合信号的能力。
Decoupling the preserved signal of environmental (allogenic) forcing from those of inter· nally generated (autogenic) processes is at the centre of understanding the evolution of the Earth's surface preserved in the sedimentary record. A major stumbling block for distinguishing between allogenic versus autogenic signatures in the stratigraphic record is the lack of quantitative understanding of autogenic processes and their interactions with allogenic forcing. Physical experiments with moving sediment and water construct topography through dynamic self-organised fluvial systems. thus providing an opportu nity to investigate autogenic processes under controlled boundary conditions (e.g. sedi ment supply and tectonics). This paper presents a set of tank experiments that are used to examine quantitatively 1) the autocyclic storage and release of secliment in the delta top surface associated with river-pattern changes between channel and sheet flow and 2) changes in fluvial autocyclic behaviour driven by external forcing (e.g. sea-level change and tectonics). The time and event scales of the autogenic processes observed in the experiments conducted without external forcing have provided the first-order quantita tive understanding of the autogenic processes. Changes in the frequency of autogenic processes through base-level changes and lateral ground tilting have provided a new view into the coupled allogenic and autogenic controls on stratigraphic development. Coupled experiments that test the effects of allogenic forcing on autogenic process are presented here: one experiment was conducted with constant external forcing and the other was conducted with cyclic changes in external controls. This review provides 1) quantitative measurements of fluvial autogenic processes and thorough comparisons of cyclic strata attributed to allogenic versus autogenic controls and 2) suggestions for future experimental studies of fluvial autogenic processes that will enhance our ability to interpret the mixed signals of environmental variation and internal dynamics in the sedimentary record.