Chirp navigation tracklines from USGS cruise 2003-003-FA along the inner continental shelf of northern North Carolina (isc2003003_tracklines.shp)

The northeastern North Carolina coastal system, from False Cape, Virginia, to Cape Lookout, North Carolina, has been studied by a cooperative research program that mapped the Quaternary geologic framework of the estuaries, barrier islands, and inner continental shelf. This information provides a basis to understand the linkage between geologic framework, physical processes, and coastal evolution at time scales from storm events to millennia. The study area attracts significant tourism to its parks and beaches, contains a number of coastal communities, and supports a local fishing industry, all of which are impacted by coastal change. Knowledge derived from this research program can be used to mitigate hazards and facilitate effective management of this dynamic coastal system.
This regional mapping project produced spatial datasets of high-resolution geophysical (bathymetry, backscatter intensity, and seismic reflection) and sedimentary (core and grab-sample) data. The high-resolution geophysical data were collected during numerous surveys within the back-barrier estuarine system, along the barrier island complex, in the nearshore, and along the inner continental shelf. Sediment cores were taken on the mainland and along the barrier islands, and both cores and grab samples were taken on the inner shelf. Data collection was a collaborative effort between the U.S. Geological Survey (USGS) and several other institutions including East Carolina University (ECU), the North Carolina Geological Survey, and the Virginia Institute of Marine Science (VIMS).
The high-resolution geophysical data of the inner continental shelf were collected during six separate surveys conducted between 1999 and 2004 (four USGS surveys north of Cape Hatteras: 1999-045-FA, 2001-005-FA, 2002-012-FA, 2002-013-FA, and two USGS surveys south of Cape Hatteras: 2003-003-FA and 2004-003-FA) and cover more than 2600 square kilometers of the inner shelf. Single-beam bathymetry data were collected north of Cape Hatteras in 1999 using a Furuno fathometer. Swath bathymetry data were collected on all other inner shelf surveys using a SEA, Ltd. SwathPLUS 234-kHz bathymetric sonar. Chirp seismic data as well as sidescan-sonar data were collected with a Teledyne Benthos (Datasonics) SIS-1000 north of Cape Hatteras along with boomer seismic reflection data (cruises 1999-045-FA, 2001-005-FA, 2002-012-FA and 2002-013-FA). An Edgetech 512i was used to collect chirp seismic data south of Cape Hatteras (cruises 2003-003-FA and 2004-003-FA) along with a Klein 3000 sidescan-sonar system. Sediment samples were collected with a Van Veen grab sampler during four of the USGS surveys (1999-045-FA, 2001-005-FA, 2002-013-FA, and 2004-003-FA). Additional sediment core data along the inner shelf are provided from previously published studies.
A cooperative study, between the North Carolina Geological Survey and the Minerals Management Service (MMS cores), collected vibracores along the inner continental shelf offshore of Nags Head, Kill Devils Hills and Kitty Hawk, North Carolina in 1996. The U.S. Army Corps of Engineers collected vibracores along the inner shelf offshore of Dare County in August 1995 (NDC cores) and July-August 1995 (SNL cores). These cores are curated by the North Carolina Geological Survey and were used as part of the ground validation process in this study.
Nearshore geophysical and core data were collected by the Virginia Institute of Marine Science. The nearshore is defined here as the region between the 10-m isobath and the shoreline. High-resolution bathymetry, backscatter intensity, and chirp seismic data were collected between June 2002 and May 2004. Vibracore samples were collected in May and July 2005.
Shallow subsurface geophysical data were acquired along the Outer Banks barrier islands using a ground-penetrating radar (GPR) system. Data were collected by East Carolina University from 2002 to 2005. Rotasonic cores (OBX cores) from five drilling operations were collected from 2002 to 2006 by the North Carolina Geological Survey as part of the cooperative study with the USGS. These cores are distributed throughout the Outer Banks as well as the mainland.
The USGS collected seismic data for the Quaternary section within the Albemarle-Pamlico estuarine system between 2001 and 2004 during six surveys (2001-013-FA, 2002-015-FA, 2003-005-FA, 2003-042-FA, 2004-005-FA, and 2004-006-FA). These surveys used Geopulse Boomer and Knudsen Engineering Limited (KEL) 320BR Chirp systems, except cruise 2003-042-FA, which used an Edgetech 424 Chirp and a boomer system. The study area includes Albemarle Sound and selected tributary estuaries such as the South, Pungo, Alligator, and Pasquotank Rivers; Pamlico Sound and trunk estuaries including the Neuse and Pamlico Rivers; and back-barrier sounds including Currituck, Croatan, Roanoke, Core, and Bogue.

北卡罗来纳州东北部沿海系统（范围涵盖弗吉尼亚州假角（False Cape）至北卡罗来纳州卢考特角（Cape Lookout））已由一项合作研究计划开展研究，该计划完成了河口（estuaries）、障壁岛（barrier islands）以及内陆陆架（inner continental shelf）的第四纪（Quaternary）地质框架填图工作。该研究成果可为理解地质框架、物理过程与海岸演化之间的关联提供基础，研究的时间尺度涵盖从风暴事件到千年尺度的范围。研究区域内的公园与海滩拥有极高的旅游吸引力，分布有多个沿海社区，并支撑着当地渔业，上述所有产业均受到海岸变化的影响。本研究计划所获取的认知可用于减缓海岸灾害风险，并助力该动态沿海系统的高效管理。
本区域填图项目生成了高分辨率地球物理数据（涵盖水深测量（bathymetry）、背散射强度（backscatter intensity）与地震反射（seismic reflection）数据）与沉积数据（包含岩芯（core）与抓取采样（grab-sample）数据）的空间数据集。高分辨率地球物理数据采集自障后河口系统（back-barrier estuarine system）、障壁岛群、近岸区域以及内陆陆架的多次勘测工作。沉积岩芯采集于大陆沿岸与障壁岛区域，而内陆陆架则同时采集了岩芯与抓取采样样品。数据采集工作由美国地质调查局（U.S. Geological Survey, USGS）与包括东卡罗来纳大学（East Carolina University, ECU）、北卡罗来纳州地质调查局以及弗吉尼亚海洋科学研究所（Virginia Institute of Marine Science, VIMS）在内的多家机构合作完成。
内陆陆架的高分辨率地球物理数据采集自1999年至2004年间开展的6次独立勘测（其中4次为哈特拉斯角（Cape Hatteras）以北的USGS勘测：1999-045-FA、2001-005-FA、2002-012-FA、2002-013-FA；另外2次为哈特拉斯角以南的USGS勘测：2003-003-FA与2004-003-FA），覆盖面积超过2600平方千米的内陆陆架区域。1999年，研究团队使用古野（Furuno）测深仪（fathometer）完成了哈特拉斯角以北的单波束水深测量数据采集工作。其余所有内陆陆架勘测均使用SEA有限公司的SwathPLUS 234千赫兹测深声呐完成了条带测深（swath bathymetry）数据采集。哈特拉斯角以北区域采用Teledyne Benthos（Datasonics）SIS-1000采集了啁啾地震（chirp seismic）数据与侧扫声呐（sidescan-sonar）数据，并同步采集了boom地震反射数据（涉及1999-045-FA、2001-005-FA、2002-012-FA与2002-013-FA四次勘测航次）。哈特拉斯角以南区域则采用Edgetech 512i采集啁啾地震数据，并搭配Klein 3000侧扫声呐系统完成侧扫数据采集（涉及2003-003-FA与2004-003-FA两次勘测航次）。研究团队在四次USGS勘测航次（1999-045-FA、2001-005-FA、2002-013-FA与2004-003-FA）中采用Van Veen抓取采样器完成了沉积样品采集。内陆陆架的额外沉积岩芯数据源自已发表的过往研究。
1996年，北卡罗来纳州地质调查局与矿产管理服务局（Minerals Management Service, MMS cores）合作开展了一项研究，在北卡罗来纳州纳格斯黑德、基尔迪维尔丘陵与基蒂霍克近岸的内陆陆架区域采集了振动岩芯（vibracore）样品。美国陆军工程兵团于1995年8月（NDC岩芯）与1995年7-8月（SNL岩芯）在戴尔县近岸的内陆陆架区域采集了振动岩芯样品。上述岩芯由北卡罗来纳州地质调查局负责保管，并作为本次研究地面验证工作的一部分得以应用。
弗吉尼亚海洋科学研究所完成了近岸区域的地球物理与岩芯数据采集工作。本次研究中，近岸区域被定义为水深10米等深线（10-m isobath）与海岸线之间的区域。研究团队于2002年6月至2004年5月间采集了高分辨率水深测量、背散射强度与啁啾地震数据。振动岩芯样品采集于2005年5月与7月。
研究团队采用探地雷达（ground-penetrating radar, GPR）系统在外岸障壁岛（Outer Banks barrier islands）区域采集了浅部地下地球物理数据。东卡罗来纳大学于2002年至2005年间完成了上述数据的采集工作。北卡罗来纳州地质调查局作为与USGS合作研究的一部分，于2002年至2006年间通过五次钻探作业采集了旋转声波岩芯（rotasonic cores, OBX cores）样品。上述岩芯分布于外岸区域与大陆沿岸各地。
USGS于2001年至2004年间通过六次勘测航次（2001-013-FA、2002-015-FA、2003-005-FA、2003-042-FA、2004-005-FA与2004-006-FA）完成了阿尔伯马尔-帕姆利科河口系统（Albemarle-Pamlico estuarine system）内第四纪地层的地震数据采集工作。除2003-042-FA航次采用Edgetech 424啁啾系统与boom震源系统外，其余勘测航次均采用Geopulse Boom与Knudsen工程有限公司（Knudsen Engineering Limited, KEL）320BR啁啾系统开展数据采集。本次研究区域涵盖阿尔伯马尔湾（Albemarle Sound）及其选定的支流河口（如南河、庞戈河、短吻鳄河与帕斯阔坦克河）、帕姆利科湾（Pamlico Sound）及其主干河口（如纽斯河与帕姆利科河），以及障后海湾（back-barrier sounds）（包括库里塔克湾、克罗阿坦湾、罗阿诺克湾、科尔湾与博格湾）。