Interpretation of sea-floor geologic units on the Massachusetts inner continental shelf between Nahant and Northern Cape Cod Bay (Nahant_CCB_surfgeol polygon shapefile; Geographic 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/.

本数据集包含经定性推导得到的解释性多边形形状文件（shapefile）与精选源栅格数据（raster data），用于定义从纳汉特（Nahant）至科德角湾北部海域的海底表层地质学、沉积物类型与分布，以及海底地貌分区（physiographic zone）。本研究生成解释图层所使用的大部分地球物理数据，由马萨诸塞州海岸带管理办公室（Massachusetts Office of Coastal Zone Management, 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（National Oceanic and Atmospheric Administration, NOAA）以及美国陆军工程兵团（U.S. Army Corps of Engineers, USACE）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信息，以服务于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重要前置步骤。本项目聚焦马萨诸塞州沿海近岸海域。由美国地质调查局主导的制图合作项目所采集的数据，已以系列《美国地质调查局公开文件报告》（USGS Open-File Report）的形式发布，详情可访问：http://woodshole.er.usgs.gov/project-pages/coastal_mass/html/current_map.html。本研究发布的解释结果覆盖范围为马萨诸塞州纳汉特南端至科德角湾北部海域。本次数据解释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（bathymetry）数据、激光雷达（lidar）数据、声学后向散射强度（acoustic-backscatter intensity）数据、地震反射剖面、海底照片以及沉积物样品。大部分近岸地球物理与采样数据（含海底照片）采集于2000年至2008年间的多次科考航次。有关本次航次与采集数据的更多信息，可访问马萨诸塞州近海海底地质制图专题网页：http://woodshole.er.usgs.gov/project-pages/coastal_mass/。