Thermal Structure of the Cascadia Subduction Zone on the Washington Margin

华盛顿边缘卡斯卡迪亚俯冲带的热结构

• 批准号: 1144164
• 负责人: Harlan Johnson
• 金额: $ 38.78万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1144164&HistoricalAwards=false
• 关键词: Thermal; Structure; Cascadia; Subduction; Zone

To obtain an accurate estimate of conductive heat flux from the Cascadia accretionary prism, the PIs plan redundant methods to obtain both thermal and fluid flux measurements along a 2.5 D profile of the margin at a single latitude. In this profile they will use thermal blankets suitable for impenetrable sub-stratum, continuous fluid flow meters, multi-core deployments for sediment pore-water chemistry and thermal gradient measurements, and Jason-II heat flow probes. The heat flow and fluid flux data will be obtained at 10 specific equally-spaced depth intervals, along the margin from 2900 m to 500 m depths. The heat flow profile would also coincide spatially with other large-scale NSF programs planned for the Washington corridor at 47°N, including the OBSIP (Ocean Bottom Seismometer) focused deployment site, Endurance Array moorings for OOI, high resolution EM302 bathymetry surveys, and an Open Access 3-D MCS volume using the LANGSETH. The goal would be to obtain data of sufficient quality that downward projection of the surficial thermal gradients to the CSZ décollement and igneous basement can be made with reasonable confidence.The Open Data Access strategy developed by the MCS community is the new paradigm for geophysical data that has wide community interest, and we plan to follow that model. The planned heat flow, fluid flux and companion geophysical data will be made publically available (via GeoPRISM and UW web sites) in preliminary form, within 3 months of the end of the cruise. The project will also incorporate UW graduate and undergraduate students, as well as students from other institutions in the cruises and equipment development. The Grays Canyon area is within the treaty fishing zone of the Quinault Indian Nation, and the PIs plan to include students and teachers from the Tahola High School and Cascadia Community College in the field program.

为了准确估计卡斯卡迪亚吸积棱镜的传导热通量，PI计划采用多余的方法来获得沿单纬度边缘的2.5D剖面的热通量和流体通量测量。在这一剖面中，他们将使用适用于无法渗透的下层的热毯、连续流体流量计、用于沉积物孔隙水化学和热梯度测量的多芯部署，以及Jason-II热流探头。热流和流体通量数据将在10个特定的等间距深度间隔内获得，沿2900米到500米深度的边缘。热流分布还将在空间上与计划在北纬47°的华盛顿走廊进行的其他大型NSF项目相一致，包括集中部署OBSIP(海底地震仪)的部署地点、用于OOI的耐力阵列系泊设备、高分辨率EM302水深测量和使用朗塞特的开放式获取3-D MCS体积。目标是获得足够高质量的数据，以便能够合理自信地将地表温度梯度向下投影到CSZ裂陷和火成岩基底。由MCS社区开发的开放数据访问策略是具有广泛社区兴趣的地球物理数据的新范例，我们计划遵循该模型。计划的热流、流体流量和伴随的地球物理数据将在巡航结束后3个月内以初步形式公开(通过GeoPRISM和UW网站)。该项目还将包括密歇根大学的研究生和本科生，以及来自其他机构的学生参与巡航和设备开发。格雷斯峡谷地区位于奎诺印第安人的条约捕鱼区内，PI计划将塔霍拉高中和卡斯卡迪亚社区学院的学生和教师纳入实地计划。