Carbonate sedimentary successions that developed on isolated oceanic islands typically comprise a series of unconformity-bounded packages of strata that reflect eustatic sea level changes superimposed on local tectonic movements. Resolving the subsidence and/or uplift of these islands, which are often assumed to have simple tectonic histories, is challenging because the tectonic movements are commonly of similar magnitudes to the eustatic oscillations. The uncertainty associated with each of the components involved in the construction of subsidence diagrams (e.g., age constraints, decompaction, eustatic sea level curves, paleobathymetry), therefore, introduces significant error margins when assessing the tectonic histories of isolated carbonate platforms. By using two end-member subsidence diagrams for the Paleogene to Neogene successions on Grand Cayman and Cayman Brac, it can be shown that their subsidence rates were heterogeneous over time and that the evolution of these islands vary significantly even though they are situated in the same basin. Although these islands, located 150 km apart, were subject to uniform changes in eustatic sea level, they have different stratigraphic architectures owing to their independent tectonic histories. From the Oligocene to the late Pliocene, the tectonic histories of Grand Cayman and Cayman Brac were analogous, and they subsided at a rate of 5.6 to 9.9 m/Myr. From the late Pliocene to ~400 ka, however, northeast Cayman Brac was uplifted by 165 m and tilted with a rotational axis offshore from the southwest end of the island, whereas Grand Cayman was uplifted by ~10 m with no rotational component. The results of this study challenge the assumption that isolated carbonate platforms have simple tectonic histories, while exploring and highlighting the common problems that are encountered with the construction of subsidence diagrams.

在孤立的海洋岛上发育的碳酸盐沉积层序通常包括一系列不整合边界的地层包裹，这些地块反映了叠加在局部构造运动上的向海平面变化的欣喜变化。解决这些岛的下沉和/或隆升（通常被认为具有简单的构造历史）具有挑战性，因为构造运动的幅度通常与平地振荡相似。因此，与沉陷图构造中涉及的每个组件相关的不确定性（例如年龄限制，失压，海平面曲线欣快，古生物学），在评估孤立的碳酸盐岩平台的构造历史时会引入明显的误差幅度。通过使用大开曼岛和开曼布拉克岛上的古近纪至新近纪演替的两个最终成员沉降图，可以表明它们的沉降率随时间变化，即使这些岛位于相同的位置，它们的演化也有很大差异。盆地。尽管这些岛位于相距150公里处，但它们的欢乐海平面会发生统一变化，但由于它们具有独立的构造历史，它们具有不同的地层结构。从渐新世到上新世晚期，大开曼和开曼布拉克的构造历史是相似的，它们以每年5.6至9.9 m的速度消退。但是，从上新世晚期到约400 ka，开曼布拉克岛东北部抬升了165 m，并用旋转轴从该岛的西南端向海上倾斜，而大开曼岛则被提升了约10 m，没有旋转分量。这项研究的结果挑战了这样一个假设，即孤立的碳酸盐岩台地具有简单的构造历史，同时探索并突出了构造沉降图时遇到的常见问题。