Barrier islands throughout the world are increasingly stressed due to accelerating sea-level rise (SLR), increasing storminess, and diminishing sediment supplies. This condition is particularly evident along the Louisiana coast because it has one of the highest rates of relative SLR in the world and very limited sand sources. One of the keys in predicting how barrier islands will change in the future is to understand how they have evolved since their formation. Historical shoreline changes are usually insufficient, because those records only provide a glimpse of a barrier's history. Moreover, the data needed to decipher barrier evolution at an intermediate scale (~10¹–10³ years) is lacking for many coastal Louisiana barrier systems. One method for tracking barrier island development through time makes use of optically stimulated luminescence (OSL) dating of beach ridge sediments. This study combines OSL and the analysis of aerial imagery and previous core logs to document the timing of beach ridge formation, rates of progradation, and geologic framework of the only developed barrier island in Louisiana.

Grand Isle is composed of prograding beach ridges organized in distinct, unconformable sets. Ridges increase in spacing from west to east, due to increased rates of shoreline progradation caused by decreased accommodation space. Proto-Grand Isle began forming approximately 750 years ago, prograded northeastward until approximately 620 years ago when sediment supply slowed and/or major storms impacted the island. During that time, much the seaward portion of the existing ridges were eroded. Following truncation of the first set of beach ridges (Group 1), the island once again began to prograde in a slightly more eastward direction (Group 2 ridge sets). OSL dates indicate the island's central ridges (Group 2, ridge sets 7–9) formed between 370 ± 30 and 170 ± 10 years ago at an average rate of one ridge every 14.8 years, or progradation rate of 14.9 m/yr.

The island's sediment source comes from an eroding beach ridge plain of the Caminada headland to the west. The volume of Grand Isle's barrier lithosome is 9.26 × 10⁷ m³, which computes to an average northeasterly longshore transport rate of 128,625 m³/yr. This is a high longshore transport rate for the relatively low wave energy of this coast (H_s = 0.6 m) but is explained by hurricane impacts that substantially increase average sand transport conditions. The substantial thickness of the Grand Isle barrier lithosome (~10 m) and its steady supply of sediment contribute to the island's stability in contrast to other barrier systems along the Louisiana coast.

由于海平面上升（SLR）加速，暴风雨增加和沉积物供应减少，世界各地的隔离岛面临的压力越来越大。在路易斯安那州沿岸，这种情况尤为明显，因为它是世界上相对单反率最高的国家之一，并且沙源非常有限。预测未来障壁岛将如何变化的关键之一是了解它们自形成以来的演变过程。历史海岸线的变化通常是不够的，因为这些记录仅提供了屏障历史的一瞥。此外，需要以中等规模（〜10 ¹ –10 ³ 许多沿海路易斯安那屏障系统缺乏。通过时间跟踪障碍岛发展的一种方法是利用海滩脊沉积物的光激发发光（OSL）测年。这项研究将OSL与航空影像分析和以前的岩心记录相结合，以记录路易斯安那州唯一发达的障碍岛的海滩山脊形成的时间，渐进速率和地质框架。

大岛（Grand Isle）由渐进的沙滩山脊组成，这些山脊被组织成不同的，不整合的区域。由于居住空间的减少，脊线从西部到东部的间距增加了，这是由于海岸线渐增的速度所致。原始大岛在大约750年前开始形成，向东北推进，直到大约620年前，沉积物供应放缓和/或大风暴影响了该岛。在此期间，现有山脊的大部分向海部分被侵蚀了。在第一组海滩山脊（第1组）被截断之后，该岛再次开始向稍微偏东的方向（第2组山脊组）发展。OSL日期表明该岛的中央山脊（第2组，山脊组7-9）形成于370±30到170±10年前，平均每14.8年有一个山脊，

该岛的沉积物来源来自西面Caminada岬角的侵蚀性海滩山脊平原。Grand Isle的屏障脂质体的体积为9.26×10 ⁷ m ³，计算得出的东北东北岸平均运输速率为128,625 m ³ / yr。对于该海岸相对较低的波能（H _s  = 0.6 m），这是一个高的沿岸运输速率，但是可以通过飓风的影响来解释，这大大增加了平均砂的运输条件。与沿着路易斯安那州沿岸的其他屏障系统相比，大岛屏障脂质体的厚薄（约10 m）及其稳定的沉积物供应对该岛的稳定性起了作用。