Morphology is one of the principal driving forces governing the sedimentology and evolution of delta-canyon-fan systems. However, quantified and systematic studies of morphological controls are still very limited. This study applied hydraulic-based stratigraphic forward modelling to investigate the impacts of morphological parameters on sediment budget partitioning and channel network of delta-canyon-fan systems on passive margins. A total of six sets of stratigraphic forward models are built using 47 initial bathymetries with six varying morphological parameters: shelf gradient; shelf width; slope gradient; canyon sinuosity; canyon depth; and basin gradient. The quantified relationships between morphological parameters and sedimentological parameters (dimensions, deposition/erosion volume/area, number of tributaries and slope channels) are investigated. The causes behind the relationships are explored by analyzing the response of qualified sedimentary features to morphological controls, such as grain-size distribution, channel migration and sequence stratigraphic frame. The results suggest that low shelf gradient, low shelf width, high canyon gradient and low canyon sinuosity are beneficial for sediment budget partitioning into deep basins and turbidity currents to flow inside canyons. Low canyon depth also promotes sediment delivery but results in more channels on canyon flanks. For the delta, channel lateral migration increases then decreases with increasing shelf gradient due to the gradient threshold in determining channel sinuosity; delta size increases then stops increasing with increasing shelf width due to the shelf width threshold in determining the balance between accommodation and sediment supply. For the canyon, low canyon gradient, high canyon sinuosity and low canyon depth have similar effects on canyons, all resulting in significant channel translation and canyon widening but less canyon head retrogradation. This study improves the knowledge of controlling factors and sediment transport regime of a delta–canyon–fan system. Moreover, the observed relationships could provide semi-quantitative guidelines to predict the dimensions of delta–canyon–fan systems and the distribution of hydrocarbon reservoirs.

中文翻译：

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三角洲峡谷扇系统的形态控制：来自地层正演模型的见解

形态学是控制三角洲-峡谷-扇系统沉积学和演化的主要驱动力之一。然而，形态控制的量化和系统研究仍然非常有限。本研究应用基于水力的地层正演模拟研究形态参数对沉积物预算划分和三角洲峡谷扇系统通道网络对被动边缘的影响。使用 47 个初始测深和 6 个不同的形态参数建立了总共 6 组地层正演模型：陆架梯度；货架宽度；坡度；峡谷弯曲度；峡谷深度；和盆地梯度。形态参数与沉积学参数（维度、沉积/侵蚀体积/面积、支流和斜坡渠道的数量）进行了调查。通过分析符合条件的沉积特征对粒度分布、河道运移和层序地层格架等形态控制的响应，探讨了这些关系背后的原因。结果表明，低陆架梯度、低陆架宽度、高峡谷梯度和低峡谷弯曲度有利于沉积物预算分配到深盆地和浊流在峡谷内流动。低峡谷深度也促进沉积物输送，但导致峡谷两侧有更多通道。对于三角洲，由于确定河道弯曲度的梯度阈值，随着陆架梯度的增加，河道横向迁移先增加后减少；由于陆架宽度阈值在确定住宿和沉积物供应之间的平衡时，三角洲尺寸随着陆架宽度的增加而增加然后停止增加。对于峡谷，低峡谷梯度、高峡谷弯曲度和低峡谷深度对峡谷的影响相似，均导致显着的河道平移和峡谷加宽，但峡谷头回生较少。本研究提高了对三角洲-峡谷-扇系统控制因素和泥沙输送机制的认识。此外，观察到的关系可以为预测三角洲-峡谷-扇系统的维度和油气藏的分布提供半定量的指导。高峡谷弯曲度和低峡谷深度对峡谷的影响相似，都导致显着的河道平移和峡谷加宽，但峡谷头回生较少。本研究提高了对三角洲-峡谷-扇系统控制因素和泥沙输送机制的认识。此外，观察到的关系可以为预测三角洲-峡谷-扇系统的维度和油气藏的分布提供半定量的指导。高峡谷弯曲度和低峡谷深度对峡谷的影响相似，都导致显着的河道平移和峡谷加宽，但峡谷头回生较少。本研究提高了对三角洲-峡谷-扇系统控制因素和泥沙输送机制的认识。此外，观察到的关系可以为预测三角洲-峡谷-扇系统的维度和油气藏的分布提供半定量的指导。