Collaborative Research: Neogene history of mass transport deposits offshore North Carolina

合作研究：北卡罗来纳州近海大规模运输沉积物的新近纪历史

• 批准号: 2140397
• 负责人: Hugh Daigle
• 金额: $ 74.87万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-05-01 至 2025-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2140397&HistoricalAwards=false
• 关键词: Collaborative; Research; Neogene; history; mass

Submarine landslides are a common seafloor feature of the North Atlantic passive margin on both sides of the ocean; their presence on the Eastern North American Margin is the rule rather than the exception. They threaten large population centers along these coasts with possible tsunamis, and move material from the shallow to the deep sea during margin evolution. Despite their high prevalence on passive margins and in particular, on the U.S. east coast, very little about their causes, mechanical behavior, and frequency is understood, and their role in the development of the passive margin as it exists today has not been examined. This project will collect new seismic data with the R/V Marcus Langseth to examine large submarine landslide behavior over the past 23 million years in a region offshore North Carolina that has experienced large, recent submarine landslides. Sediment cores will be retrieved from the Cape Fear Slide, which is the most recent large submarine landslide in the area and still expressed on the seafloor. The cores will provide insights into pre-conditioning and triggering mechanisms. This study will improve understanding of how slope failures operate through time and the manner in which past events might influence subsequent events, and will provide training and international collaboration opportunities for three graduate students and three early-career scientists.This project will collect high-resolution multichannel seismic data and piston cores on the continental rise and slope in the vicinity of the Cape Fear submarine landslide offshore North Carolina. These data will be used to examine the interplay between margin topography, fluid and heat flow, pore pressure, and submarine mass transport deposits. Mass transport deposits, bottom-simulating reflections, and stratigraphic sequences in the Cape Fear region will be seismically imaged. The new high-resolution seismic data will be combined with existing seismic and borehole data to interpret number of events, timing, source areas, volumes, areal extent and runout length, and bounding surfaces of mass transport deposits. The seismic data will be used to assess and model internal characteristics of mass transport deposits and surrounding sediments, including deformation style, present-day pore pressure and temperature distribution, and the presence of gas. This project consists of acquiring 3843 km of 2D high-resolution multichannel seismic data, along with bathymetry, subbottom profiler, and water column data. Seven piston and seven gravity cores will be collected in locations associated with seeps or bottom-simulating reflections. Geotechnical and pore fluid chemical analyses will be performed. The processed seismic data will be interpreted for stratigraphic age control, areal extent, and volume of mass transport deposits. Internal deformation of mass transport deposits will be examined through seismic attribute analysis. Sediment physical properties will be derived using full waveform inversion and quantitative models of conditions for failure will be developed. The results of this project will be relevant to understanding submarine landslides dynamics on passive margins with similar characteristics worldwide.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

海底滑坡是北大西洋被动边缘在大洋两岸常见的海底特征；它们在北美东部边缘的存在是一种规律，而不是例外。它们可能引发海啸，威胁沿海地区的人口密集地区，并在边缘进化过程中将物质从浅海转移到深海。尽管它们在被动边缘地带非常普遍，特别是在美国东海岸，但人们对它们的原因、机械行为和频率知之甚少，它们在被动边缘地带发展中的作用也没有得到研究。该项目将与R/V Marcus Langseth一起收集新的地震数据，以检查过去2300万年来北卡罗来纳州近海地区的大型海底滑坡行为，该地区最近经历了大型海底滑坡。沉积物岩心将从Cape Fear滑坡中提取，这是该地区最近发生的大型海底滑坡，目前仍在海底发生。这些核心将提供对预调节和触发机制的见解。这项研究将提高人们对边坡破坏如何随时间变化以及过去事件可能影响后续事件的方式的理解，并将为三名研究生和三名早期职业科学家提供培训和国际合作机会。该项目将收集高分辨率的多通道地震数据和活塞岩心，这些数据来自于北卡罗莱纳州近海Cape Fear海底滑坡附近的大陆隆起和斜坡。这些数据将用于研究边缘地形、流体和热流、孔隙压力和海底物质搬运沉积之间的相互作用。将对开普菲尔地区的块体搬运沉积、模拟底反射和地层层序进行地震成像。新的高分辨率地震数据将与现有的地震和钻孔数据相结合，以解释事件的数量、时间、震源区域、体积、面积范围和跳动长度以及质量搬运矿床的边界面。地震数据将用于评估和模拟质量搬运沉积物和周围沉积物的内部特征，包括变形样式、现今孔隙压力和温度分布以及气体的存在。该项目包括获取3843公里的2D高分辨率多通道地震数据，以及测深、海底剖面和水柱数据。七个活塞和七个重力岩心将在与渗漏或模拟底部反射有关的位置收集。将进行岩土和孔隙流体化学分析。处理后的地震资料将用于解释地层年龄控制、块状搬运矿床的面积范围和体积。通过地震属性分析，探讨了块体搬运矿床的内部变形。沉积物的物理性质将使用全波形反演来推导，并将开发破坏条件的定量模型。该项目的结果将有助于了解世界范围内具有类似特征的被动边缘上的海底滑坡动力学。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。