When Is a Barrier Island Not an Island? When It Is Preserved in the Rock Record
When Is a Barrier Island Not an Island? When It Is Preserved in the Rock Record
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什么时候障壁岛不是岛屿？
DOI：
10.3389/feart.2020.560437
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
A. Green
中科院分区：
文献类型：
--
作者：
J. Mulhern;C. Johnson;A. Green
现有的障壁岛相模式主要基于现代观测。这种方法突出了障壁岛系统的异质性和动态性，但它忽略了与地质时间尺度相关的过程，如多向运动，侵蚀和改造，以及它们作为保存地层的表达。因此，本研究使用的特征露头表达式，从白垩纪上直崖形成在南部犹他州更新模型障壁岛的运动和保存，包括地质时间尺度的过程。结果表明，保存障壁岛系统的关键区别相和建筑元素与现代系统中观察到的“岛”形态关系不大。四个相组合被用来描述和表征这些障壁岛建筑元素。障壁岛与障壁后充填（FA1）相伴出现，内部包含下、上滨面（FA2）、近端上滨面（FA3）和潮汐通道相（FA4）。三个主要的建筑元素（障壁岛滨面，滨面为主的入口填充，和通道为主的入口填充）发生独立或组合，以创建堆叠障壁岛沉积。障壁岛的滨面记录的沉积，而滨面为主的入口填充记录的横向迁移，和通道为主的入口填充记录的潮汐入口内的加积。障壁岛是由泻湖或河口，并从其内部相和露头的几何形状，与障壁后相的关联，并在海侵序列中的位置与其他滨面沉积区分。潮汐过程，特别是潮汐入口迁移和改造的上滨面，也区分障壁岛的继承。总之，这项研究扩展了障壁岛相模式，并提供了新的识别标准，以解释复杂的几何形状的时间海侵，保存障壁岛存款。
Existing barrier island facies models are largely based on modern observations. This approach highlights the heterogeneous and dynamic nature of barrier island systems, but it overlooks processes tied to geologic time scales, such as multi-directional motion, erosion, and reworking, and their expressions as preserved strata. Accordingly, this study uses characteristic outcrop expressions from paralic strata of the Upper Cretaceous Straight Cliffs Formation in southern Utah to update models for barrier island motion and preservation to include geologic time-scale processes. Results indicate that the key distinguishing facies and architectural elements of preserved barrier island systems have very little to do with “island” morphology as observed in modern systems. Four facies associations are used to describe and characterize these barrier island architectural elements. Barrier islands occur in association with backbarrier fill (FA1) and internally contain lower and upper shoreface (FA2), proximal upper shoreface (FA3), and tidal channel facies (FA4). Three main architectural elements (barrier island shorefaces, shoreface-dominated inlet fill, and channel-dominated inlet fill) occur independently or in combination to create stacked barrier island deposits. Barrier island shorefaces record progradation, while shoreface-dominated inlet fill records lateral migration, and channel-dominated inlet fill records aggradation within the tidal inlet. Barrier islands are bound by lagoons or estuaries and are distinguished from other shoreface deposits by their internal facies and outcrop geometry, association with backbarrier facies, and position within transgressive successions. Tidal processes, in particular, tidal inlet migration and reworking of the upper shoreface, also distinguish barrier island successions. In sum, this study expands barrier island facies models and provides new recognition criteria to account for the complex geometries of time-transgressive, preserved barrier island deposits.
撤退障碍以在大陆架上自生形成周期性沉积物的机制
影响因子：
5.8
作者：
Ciarletta, Daniel J.;Lorenzo-Trueba, J.;Ashton, A.D.
通讯作者：
Ashton, A.D.