Elevation of paleochannel unconformities underlying the inner shelf of Long Bay (Grid)

In 1999, the U.S. Geological Survey (USGS), in partnership with the South Carolina Sea Grant Consortium, began a study to investigate processes affecting shoreline change along the northern coast of South Carolina, focusing on the Grand Strand region. Previous work along the U.S. Atlantic coast shows that the structure and composition of older geologic strata located seaward of the coast heavily influences the coastal behavior of areas with limited sediment supply, such as the Grand Strand. By defining this geologic framework and identifying the transport pathways and sinks of sediment, geoscientists are developing conceptual models of the present-day physical processes shaping the South Carolina coast. The primary objectives of this research effort are: 1) to provide a regional synthesis of the shallow geologic framework underlying the coastal upland, shoreface and inner continental shelf, and define its role in coastal evolution and modern beach behavior; 2) to identify and model the physical processes affecting coastal ocean circulation and sediment transport, and to define their role in shaping the modern shoreline; and 3) to identify sediment sources and transport pathways; leading to construction of a regional sediment budget.

1999年，美国地质调查局（U.S. Geological Survey, USGS）与南卡罗来纳海洋资助联合会（South Carolina Sea Grant Consortium）合作启动一项研究，旨在探究影响南卡罗来纳州北部海岸（重点聚焦大滩段（Grand Strand）区域）的海岸线变化过程。此前针对美国大西洋沿岸的已有研究表明，位于海岸向海一侧的古老地质地层的结构与组成，会对沉积物供给有限的区域（如大滩段）的海岸动态产生强烈影响。通过明确该地质框架并识别沉积物的输运路径与沉积汇，地球科学家正构建塑造南卡罗来纳州海岸的现代物理过程的概念模型。本研究的核心目标共有三项：1）对海岸高地、滨面与内陆架之下的浅层地质框架开展区域性综合研究，并阐明其在海岸演化与现代海滩动态中的作用；2）识别并模拟影响沿海海洋环流与沉积物输运的物理过程，明确其对现代海岸线形态的塑造机制；3）明确沉积物源区与输运路径，进而构建区域性沉积物收支平衡。