Collaborative Research: Testing models of magmatic and hydrothermal segmentation: A 3-D seismic tomography experiment at the Endeavour Ridge

合作研究：测试岩浆和热液分割模型：奋进山脊的 3D 地震层析成像实验

• 批准号: 0454700
• 负责人: William Wilcock
• 金额: $ 34.17万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2014-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0454700&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; models; magmatic

Competing models for controls on the segmentation and intensity of ridge crest processes are at odds on the scale of mantle and crustal magmatic segmentation, the distribution of hydrothermal venting with respect to a volcanic segment and the properties of the thermal boundary layer that transports energy between the magmatic and hydrothermal systems. The recent discovery of an axial magma chamber (AMC) reflector beneath the Endeavour segment of the Juan de Fuca ridge, as well as systematic along axis changes in seafloor depth, ridge crest morphology and hydrothermal venting provide an ideal target for testing conflicting hypotheses. The scientific objectives of this project are to: (1) Determine if the segmentation and intensity of the magma-hydrothermal systems at the Endeavour ridge are related to magma supply or to the magma plumbing between the mantle and crust, and (2) Constrain the thermal and magmatic structure underlying the Endeavour hydrothermal system in order to understand the patterns of energy transfer. An active source seismic tomography experiment, using an array of 64 three-component ocean-bottom seismometers, will image the 3-D seismic structure of the crust and topmost mantle along an 80-km-long section of the Endeavour ridge. The experiment will image four targets: (1) crustal thickness variations within 25 km of the axial high (0 to 900 kyr); (2) the 2-D (i.e., map view) structure of the uppermost mantle beneath the spreading axis; (3) the 3-D structure of the crustal magmatic system and (4) the detailed 3-D, shallow crustal thermal structure beneath the Endeavour vent field. The results of imaging will define the recent history of magma supply, the pattern of melt delivery from the mantle to the crust and the structure and segmentation of the subseafloor magmatic and hydrothermal systems. These measurements are essential to testing critically competing hypotheses for what regulates the intensity of ridge crest magmatic and hydrothermal processes.

控制脊顶过程的分割和强度的竞争模型在地幔和地壳岩浆分割的规模、相对于火山段的热液喷口的分布以及在岩浆和热液系统之间输送能量的热边界层的性质上存在差异。 最近在胡安·德富卡海脊的奋进段下面发现了一个轴向岩浆房反射体，以及海底深度、海脊脊顶形态和热液喷口沿沿着轴发生的系统变化，为检验相互矛盾的假设提供了一个理想的目标。 该项目的科学目标是： (1)确定奋进海岭岩浆热液系统的分段和强度是否与岩浆供应或地幔与地壳之间的岩浆管道有关，以及（2）约束奋进热液系统下的热和岩浆结构，以了解能量传递的模式。 利用64个三分量海底地震仪阵列进行的主动源地震层析成像实验将对沿沿着80公里长的奋进号海岭的地壳和地幔顶部的三维地震结构成像。 该实验将对四个目标进行成像：（1）轴向高度（0至900 kyr）25公里内的地壳厚度变化;（2）二维（即，（3）地壳岩浆系统的三维结构;（4）奋进号喷口区下面详细的三维浅部地壳热结构。 成像结果将确定岩浆供应的近期历史、从地幔到地壳的熔体输送模式以及海底下岩浆和热液系统的结构和分段。 这些测量是必不可少的，以测试严格竞争的假设是什么调节脊顶岩浆和热液过程的强度。