Geophysical Studies near the Ascension Transform: Evolution of Ridge Segmentation and Crustal Structure - Auswertung

扬升变换附近的地球物理研究：脊分段和地壳结构的演化 - 评估

• 批准号: 5415379
• 负责人: Dr. Jörg Bialas
• 金额: --
• 依托单位: Forschungseinheit Marine Geodynamik
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2003
• 资助国家: 德国
• 起止时间: 2002-12-31 至 2010-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5415379?language=en
• 关键词: Geophysical; Studies; near; Ascension; Transform

In late 2004 Meteor cruise M62/4 will collect a large geophysical dataset in the region of the Ascension Transform fault with the aim of studying the segmentation of the spreading axis. Specific questions to be addressed are: the change in crustal and upper mantle structure moving from the centre of a spreading segment towards the end and between spreading segments with a well-developed median valley and a well-developed axial high; the asymmetry between segment ends adjacent to the active transform and the inactive fracture zone (inside and outside corners respectively); the evolution of oceanic core complexes (domal exposures of deep crustal and mantle rocks exhumed by movement along detachment faults and characterised by corrugated upper surfaces). Tools to be used include: wid-angle seismic profiles to determine crustal structure and in conjunction with existing gravity data to constrain the thermal structure of the uppermost mantle; high resolution seismic reflection studies (including a deep tow streamer) to image the structure of the upper oceanic crust (faulting and magma chambers); microseismicity and tomographic studies using a grid of ocean bottom instruments to determine local 3-D crustal structure and fault activity and mechanics; swath-bathymetry and magnetics. This proposal requests support to enable the complete analysis of these data.

2004年底，流星号巡航M62/4将在Ascension转换断层区域收集大量地球物理数据集，目的是研究扩展轴的分段。具体问题是：地壳和上地幔结构从扩张段中心向端部的变化，以及中间谷和轴向高压发育的扩张段之间的变化;邻近活动转换带的扩张段端部与不活动断裂带之间的不对称性（分别为内角和外角）;大洋核杂岩的演化（地壳深部和地幔岩石的穹状出露，这些岩石因沿着拆离断层运动而被挖出，其特征是上表面呈波纹状）。使用的工具包括：宽角地震剖面图，以确定地壳结构，并结合现有重力数据，以确定最上层地幔的热结构;高分辨率地震反射研究（包括一条深拖拖缆），以拍摄上洋壳的结构（断层和岩浆房）;利用海底仪器网格进行微震活动和层析成像研究，以确定当地三维地壳结构和断层活动及力学;条带测深和磁力本提案要求提供支持，以便能够对这些数据进行全面分析。