Understanding how past coastal systems have evolved is critical to predicting future coastal change. Using over 12,000 trackline kilometers of recently collected, co-located multi-channel boomer, sparker and chirp seismic reflection profile data integrated with previously collected borehole and vibracore data, we define the upper (< 115 m below mean lower low water) seismic stratigraphic framework offshore of the Delmarva Peninsula, USA. Twelve seismic units and 11 regionally extensive unconformities (U1-U11) were mapped over 5900 km² of North America's Mid-Atlantic continental shelf. We interpret U3, U7, U9, U11 as transgressive ravinement surfaces, while U1,2,4,5,6,8,10 are subaerial unconformities illustrating distinct periods of lower sea-level. Based on areal distribution, stratigraphic relationships and dating results (Carbon 14 and amino acid racemization estimates) from earlier vibracore and borehole studies, we interpret the infilled channels as late Neogene and Quaternary courses of the Susquehanna, Potomac, Rappahannock, York, James rivers and tributaries, and a broad flood plain. These findings indicate that the region's geologic framework is more complex than previously thought and that Pleistocene paleochannels are abundant in the Mid-Atlantic. This study synthesizes and correlates the findings of other Atlantic Margin studies and establishes a large-scale Quaternary framework that enables more detailed stratigraphic analysis in the future. Such work has implications for inner continental shelf systems tract evolution, the relationship between antecedent geology and modern coastal systems, assessments of eustacy, glacial isostatic adjustment, and other processes and forcings that play a role in passive margin evolution.

了解过去的沿海系统如何演变对于预测未来的沿海变化至关重要。使用最近收集的，共处一地的多于12,000个轨迹线公里的多臂臂架，火花发生器和chi声地震反射剖面数据以及先前收集的井眼和震颤岩数据，我们定义了上部（低于平均低水位以下<115 m）地震地层框架美国Delmarva半岛的近海。在5900 km ^2上绘制了12个地震单元和11个区域性不整合面（U1-U11）北美中大西洋大陆架的一部分。我们将U3，U7，U9，U11解释为海侵的沟谷面，而U1,2、4、5、6、8、10是地下不整合面，说明了较低的海平面不同时期。根据早期震颤和钻孔研究的区域分布，地层关系和测年结果（碳14和氨基酸消旋估算值），我们将充填通道解释为萨斯奎哈纳邦，波托马克，拉帕汉诺克，约克，詹姆斯·里弗斯和支流和广阔的洪泛区。这些发现表明，该地区的地质框架比以前认为的要复杂，并且中大西洋的更新世古河道十分丰富。这项研究综合并关联了其他Atlantic Margin研究的发现，并建立了一个大型第四纪框架，可以在将来进行更详细的地层分析。这些工作对内陆大陆架系统道的演变，前期地质学与现代沿海系统之间的关系，对经济性的评估，冰川等静压调整以及在被动边缘演化中发挥作用的其他过程和强迫具有重要意义。