Variability in accommodation and sedimentation rates within a basin generates significant deviations in the along‐strike stratal stacking patterns of systems tracts. This variability can lead to coeval depositional units that record the juxtaposition of transgressive (retrogradational) and regressive (progradational) stratal stacking patterns. In scenarios where transgressive and regressive units are deposited concurrently, challenges arise when attempting to correlate and place systems tracts into a sequence stratigraphic framework. In these scenarios, the maximum flooding surface records a high level of diachroneity, with the position of the surface variable throughout the stratigraphic column. In this study, Viking Formation (late Albian) deposits in the Western Canada Sedimentary Basin, central Alberta, Canada, preserve significant along‐strike variability of palaeoshorelines that developed in response to autogenic processes as well as allogenic controls that were active during deposition. Specifically, structural reactivation of Precambrian basement structures during Viking deposition led to significant variability in depositional environments along the palaeoshoreline. The incremental basement reactivation of the Precambrian Snowbird Tectonic Zone influenced sedimentation patterns and the creation of anomalous zones of accommodation in localized areas of the basin. Across fault boundaries and within the anomalously thick strata, both progradational and retrogradational stacking patterns occur within broadly contemporaneous deposits, complicating the correlation of stratigraphic units. While the concomitant deposition of transgressive and regressive units has been documented in a number of modern marine analogues, the concept is rarely applied to ancient successions. By identifying along‐strike variabilities in shoreline geometries and incorporating the autogenic and allogenic controls that were active during deposition, a more accurate sequence stratigraphic framework can be proposed.

中文翻译：

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在加拿大艾伯塔省中部维京组的结构受控区域中海侵和正向退回地层包裹的同时期沉积

一个盆地内的容纳和沉积速率的变化会在沿系统层的沿走向地层堆积模式中产生很大的偏差。这种可变性可能导致同时期的沉积单位，这些单位记录了海侵（回生）和回归（渐进）地层堆积模式的并置。在同时放置海侵和海退单元的场景中，尝试将系统域关联起来并将其放入层序地层框架时会遇到挑战。在这些情况下，最大淹水面记录了高水平的铁斜度，并且整个地层柱中地表的位置都是可变的。在这项研究中，位于加拿大艾伯塔省中部的加拿大西部沉积盆地的维京地层（阿尔拜晚期）沉积物，保留了沿古海岸海岸线的显着的沿线变异性，这些沿线是响应自生过程以及沉积过程中活跃的同种异体控制而发展的。具体而言，在维京沉积过程中前寒武纪基底结构的结构活化导致沿古海岸线的沉积环境发生重大变化。前寒武纪雪鸟构造带的增量地下室复活影响了沉积模式，并在盆地局部地区形成了异常的居住区。跨越断层边界和异常厚的地层内，在广泛同时期的沉积物中都发生了渐进和渐进的堆积模式，使地层单位的相关性复杂化了。虽然在许多现代海洋类似物中都记录了海侵和海退单元的伴随沉积，但该概念很少应用于古代演替。通过识别海岸线几何形状的沿走动变化，并结合沉积过程中活跃的自生和同生控制，可以提出更准确的层序地层学框架。