Forced-regressive conditions have been widely described by sequence-stratigraphic conceptual models, and the resulting deposits have been widely documented in sequences and parasequences. However, how forced-regressive conditions might impact on the short-term to mid-term evolution and the high-resolution stratigraphic record (10² to 10⁵ kyr) of barred shoreline environments represents an unexplored issue. This contribution presents a bedset characterization of Lower Cretaceous, barred shoreline deposits accumulated after a relative sea-level fall. Parasequence PS400 of the Pilmatué Member in the Neuquén Basin (Argentina) comprises several bedsets, most of them bounded by transgressive surfaces. However, one of them, the bedset BS400.5, is bounded below by a high-relief surface of truncation, here interpreted as an erosional regressive surface. This surface indicates incision of the underlying deposits and the onset of forced-regressive conditions at intra–parasequence scale. The internal architecture of the studied bedset exhibits seaward-dipping clinoforms that bound clinothems within the upper-shoreface deposits. These clinoforms were interpreted as the result of seaward-shifting events during the shoreline progradation. A sequence-stratigraphic conceptual model is proposed for the high-frequency evolution of a barred shoreline under forced-regressive conditions. The model explains how the intra–bedset evolution under low and stillstand sea-level conditions and cross-shore imbalances in the sediment budget controlled the exceptional preservation of bar and rip-channel deposits.

中文翻译：

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在强制海退条件下（下白垩纪，内乌肯盆地，阿根廷）对禁止海岸线的特殊保护

层序地层概念模型已广泛描述了强迫回归条件，并且由此产生的沉积物已广泛记录在层序和准层序中。然而，强迫回归条件如何影响短期到中期的演化和高分辨率地层记录（10 ²到 10 ⁵kyr) 的禁止海岸线环境代表了一个未探索的问题。这一贡献呈现了在相对海平面下降后积累的下白垩统、禁止的海岸线沉积物的床集特征。Neuquén 盆地（阿根廷）Pilmatué 段的 Parasequence PS400 由几个地层组组成，其中大部分以海侵面为界。然而，其中之一，床架 BS400.5，其下方是一个高起伏的截断面，这里解释为一个侵蚀回归面。该表面表明下伏沉积物的切口和层内尺度的强制回归条件的开始。所研究的床组的内部结构展示了向海倾斜的斜面，这些斜面与上岸面沉积物中的斜面相结合。这些斜坡形被解释为海岸线前移期间向海移动事件的结果。提出了一种层序-地层概念模型，用于强制回归条件下禁止岸线的高频演化。该模型解释了在低海平面和静止海平面条件下的床内演化以及沉积物预算中的跨岸不平衡如何控制坝和离岸河沉积物的异常保存。