Chutes-and-pools are hybrid bedforms that occur in upper-flow-regime conditions, populating the stability field between antidunes and cyclic steps. Chutes-and-pools consist of a superimposition of a train of antidunes on a longer-wavelength cyclic-step instability. The presence of a hydraulic jump is more persistent in chutes-and-pools than the bores occasionally seen on breaking-wave antidunes, yet not permanent as over cyclic-step bedforms. The nature of chute-and-pool structures preserved in the depositional record is controlled largely by aggradation rate. This paper documents chute-and-pool structures generated beneath highly aggradational sediment density-flows at the subaqueous toe-of-slope of a Pleistocene carbonate wedge. Quarry exposures enable the morphodynamic reconstruction of the sediment-bed configuration that produced the identified structures. Wave-breaking on growing antidunes occurred without the destruction of the antidune, which deviates from observations in low-aggradation subaerial open-channel flows. The antidune build-up was followed by hydraulic jump controlled deposition in the antidune trough. Two-dimensional depth-resolved numerical simulations have been used to validate this process interpretation. The term aggradational chutes-and-pools is proposed for these bedforms, associated with the formation of build-and-fill structures consisting of interstratified convex lenses (in-phase wave regime) and concave lenses (hydraulic jump regime). Such structures contrast with the scour-and-fill structures produced by low-aggradation chutes-and-pools frequently described from subaerial open-channel-flow deposits. This study demonstrates a potential difference in flow behaviour between open-channel flows and density flows in the supercritical regime.

中文翻译：

---

高凝结斜槽池床形的沉积特征：构造和填充结构

溜槽和水池是混合床形，出现在上流状态下，填充了反沙丘和循环阶跃之间的稳定性场。溜槽和水池由一系列反沙丘叠加在较长波长的循环步长不稳定性上。与在破碎波反沙丘上偶尔看到的孔相比，在水槽和水池中水力跃迁的存在更为持久，但并非像周期性阶梯状地床那样永久存在。沉积记录中保存的溜槽和水池结构的性质在很大程度上受凝集速率控制。本文记录了在更新世碳酸盐楔形物的水底坡脚下高度凝集的沉积物密度流之下产生的溜槽和水池结构。采石场曝露使沉积物床构造的形态动力学得以重建，从而产生了确定的结构。在不断增长的抗沙尘土上发生波折而并未破坏抗沙土，这与低凝集的地下空气明渠流动中的观测结果有所不同。在反沙丘堆积之后，在反沙丘槽中进行水力跳跃控制的沉积。二维深度解析数值模拟已用于验证该过程的解释。术语 二维深度解析数值模拟已用于验证该过程的解释。术语 二维深度解析数值模拟已用于验证该过程的解释。术语提出了针对这些床型的集水槽和水池，与由分层凸透镜（同相波域）和凹透镜（液压跳跃域）组成的构建和填充结构的形成有关。这样的结构与经常从地下明渠流沉积物中描述的低凝结溜槽和池所产生的冲刷-充填结构形成对比。这项研究表明，在超临界状态下，明渠流量和密度流量之间的行为存在潜在差异。