Structure of rifted continental margins and gas hydrates

裂谷大陆边缘的结构和天然气水合物

• 批准号: 8459-2006
• 负责人: Louden, Keith
• 金额: $ 3.91万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2008
• 资助国家: 加拿大
• 起止时间: 2008-01-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=389760
• 关键词: Structure; rifted; continental; margins; gas

Rifted continental margins form during breakup of the continental lithosphere, as a major part of the Earth's plate tectonic cycle. The purpose of this proposal is to investigate the nature of this process by defining structures formed across the rifted margins of eastern Canada and their associated margin conjugates. These structures are determined by combining wide-angle seismic velocity models with deep multi-channel reflection data to produce integrated depth profiles. We have recently collected a number of such profiles across the eastern Canadian margins. I will complete the analysis of these data and combine them with similar profiles across the conjugate margins of NW Africa and NW Europe. Reconstructing the geometry of the crust and sediment during continental extension and comparison with recent theoretical models will help to identify fundamental attributes of the extensional processes. A key element is to understand the enigmatic nature of basement and mantle within the continent-ocean transition zone. Existing seismic models indicate that this zone can exhibit significant variability along strike of the margin, possibly related to the location of accommodation zones where rifting geometries suddenly change. I will study two such regions previously identified offshore Canada and Greenland using new seismic data with improved resolution and new processing and modeling procedures. Continental margins also contain major deposits of the world's hydrocarbon resources, both in conventional form as deep oil and gas reservoirs and in unconventional form as shallow methane trapped in hydrate structures. If released to the atmosphere, this methane could also form a potent source of greenhouse gas, potentially resulting in rapid warming. A second focus of this proposal will be to better define the nature of hydrates off eastern Canada, which have only recently been identified.

大陆岩石圈破裂期间裂谷的大陆边缘形成，是地球板块构造周期的主要部分。该提案的目的是通过定义跨加拿大东部裂痕及其相关边缘缀合物形成的结构来研究这一过程的性质。这些结构是通过将广角地震速度模型与深层多通道反射数据相结合以产生集成深度曲线来确定的。我们最近在加拿大东部的边缘收集了许多此类概况。我将完成对这些数据的分析，并将它们与非洲和西北欧洲的共轭边缘的相似概况相结合。在大陆扩展期间重建地壳和沉积物的几何形状以及与最新理论模型的比较将有助于识别扩展过程的基本属性。一个关键要素是了解大陆 - 海洋过渡区域内地下室和地幔的神秘性质。现有的地震模型表明，该区域在边缘的打击沿罢工时表现出很大的可变性，这可能与住宿区域的位置有关，在该区域的位置突然改变了几何形状。我将使用具有改进的分辨率以及新的处理和建模程序的新地震数据来研究两个以前确定的加拿大海上加拿大和格陵兰岛的区域。大陆边缘还包含世界上碳氢化合物资源的主要沉积物，无论是常规形式，都作为深油和天然气储层，以及非常规形式，因为被困在水合物结构中的浅甲烷。如果释放到大气中，这种甲烷也可能形成有效的温室气体来源，可能导致快速变暖。该提案的第二个重点将是更好地定义加拿大东部水合物的性质，而加拿大东部直到最近才被确定。