Isochron of Holocene fluvial and estuarine (Qfe) sediment thickness beneath the Massachusetts inner continental shelf between Nahant and Northern Cape Cod Bay (qfeiso Esri binary grid; UTM, Zone 19N, WGS 84)

These data are qualitatively derived interpretive polygon shapefiles and selected source raster data defining surficial geology, sediment type and distribution, and physiographic zones of the sea floor from Nahant to Northern Cape Cod Bay. Much of the geophysical data used to create the interpretive layers were collected under a cooperative agreement among the Massachusetts Office of Coastal Zone Management (CZM), the U.S. Geological Survey (USGS), Coastal and Marine Geology Program, the National Oceanic and Atmospheric Administration (NOAA), and the U.S. Army Corps of Engineers (USACE). Initiated in 2003, the primary objective of this program is to develop regional geologic framework information for the management of coastal and marine resources. Accurate data and maps of seafloor geology are important first steps toward protecting fish habitat, delineating marine resources, and assessing environmental changes because of natural or human effects. The project is focused on the inshore waters of coastal Massachusetts. Data collected during the mapping cooperative involving the USGS have been released in a series of USGS Open-File Reports (http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html). The interpretations released in this study are for an area extending from the southern tip of Nahant to Northern Cape Cod Bay, Massachusetts. A combination of geophysical and sample data including high resolution bathymetry and lidar, acoustic-backscatter intensity, seismic-reflection profiles, bottom photographs, and sediment samples are used to create the data interpretations. Most of the nearshore geophysical and sample data (including the bottom photographs) were collected during several cruises between 2000 and 2008. More information about the cruises and the data collected can be found at the Geologic Mapping of the Seafloor Offshore of Massachusetts Web page: http://woodshole.er.usgs.gov/project-pages/coastal_mass/.本数据集包含定性推导得到的解译多边形形状文件，以及用于界定纳翰特至科德角湾北部海域海底表层地质、沉积物类型与分布及地貌分区的精选原始栅格数据。用于制作解译图层的大部分地球物理数据，由马萨诸塞州海岸带管理办公室（CZM）、美国地质调查局（U.S. Geological Survey, USGS）、海岸与海洋地质学计划、美国国家海洋和大气管理局（NOAA）以及美国陆军工程兵团（USACE）通过合作协议联合采集。该项目于2003年启动，核心目标是构建区域地质框架数据集，以支撑海岸与海洋资源的管理工作。精准的海底地质数据与地图，是保护鱼类栖息地、划定海洋资源范围以及评估自然或人为因素引发的环境变化的首要基础环节。本项目聚焦马萨诸塞州沿岸近岸海域。由美国地质调查局参与的该制图合作项目所采集的数据，已以《美国地质调查局公开文件报告》（USGS Open-File Reports）系列形式发布，相关链接为http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html。本研究发布的解译成果覆盖范围为马萨诸塞州纳翰特南端至科德角湾北部的海域。本次解译工作综合利用了多类地球物理与采样数据，包括高分辨率水深测量数据、激光雷达（lidar）数据、声学背散射强度数据、地震反射剖面数据、海底摄影资料以及沉积物采样样品。本项目的近岸地球物理与采样数据（含海底摄影资料）大多采集于2000年至2008年间的多次科考航次。如需了解更多关于科考航次与采集数据的相关信息，可访问马萨诸塞州外海海底地质制图项目官方网页：http://woodshole.er.usgs.gov/project-pages/coastal_mass/。