Structure and Accretion at Mid-Ocean Ridges With High Magma Supply: Perspectives From Seafloor Escarpments and Iceland
Structure and Accretion at Mid-Ocean Ridges With High Magma Supply: Perspectives From Seafloor Escarpments and Iceland
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高岩浆供应的大洋中脊的结构和增生：来自海底悬崖和冰岛的视角
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发表时间：
2013
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通讯作者：
A. J. Horst
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作者：
A. J. Horst
尽管有大量关于洋底的数据，但对大洋中脊扩张中心的作用过程和覆盖地球表面约2/3的海洋岩石圈的产生知之甚少。特别是，地质学家不确定这些不同板块边界之下的岩浆和构造过程的具体细节，以及这些过程如何沿沿着变化。结合联合收割机地质关系和磁特性的研究继续为了解和限制海底扩张过程提供基本工具。本论文包括一系列旨在描述高岩浆供应区洋壳构造地质和磁性特征的研究。一个简短的概述是在介绍三个单独的章节，被认为是个人的贡献。第一章介绍了来自席状岩脉的古地磁和构造数据，这些数据与区域地质关系相结合，用于约束暴露在东太平洋隆起扩张裂谷尖端的洋壳的变形和构造历史。第二章描述了来自海底暴露的席状岩脉的磁组构，这些磁组构为快速扩张的洋脊下的岩浆流动方向提供了证据，这些洋脊具有较高且相对连续的岩浆供应。第三章提供了古地磁证据，以支持在冰岛北部的迁移转换断层带，可能会表现出类似的运动学其他海洋变换地壳块体的显着旋转的结构观测。大洋中脊高岩浆活动区的构造和增生作用：海底碎屑岩和冰岛的观点
Despite vast amounts of data about the ocean floor, very little is known about processes operating at mid-ocean ridge spreading centers and the generation of oceanic lithosphere that covers approximately 2/3 of Earth’s surface. In particular, geologist are uncertain about specific details of magmatic and tectonic processes beneath these divergent plate boundaries and how these processes may vary along the spreading axis. Investigations that combine geologic relationships and magnetic properties continue to yield fundamental tools for understanding and constraining seafloor spreading processes. This thesis contains a collection of studies designed to characterize structural geology and magnetic properties of oceanic crust formed in regions with high magma supply. A brief overview is provided in an introduction to three separate chapters that are considered individual contributions. Chapter one presents paleomagnetic and structural data from sheeted dikes that are used in combination with regional geologic relationships to constrain the deformation and tectonic history of oceanic crust exposed at the tip of a propagating rift on the East Pacific Rise. Chapter two describes the magnetic fabrics of sheeted dikes from seafloor exposures that provide evidence for a wide range of magma flow directions beneath fast-spreading ridges with high and relatively continuous magma supply. Chapter three provides paleomagnetic evidence to support structural observations for significant rotations of crustal blocks within a migrating transform fault zone in North Iceland that may exhibit similar kinematics to other oceanic transforms. STRUCTURE AND ACCRETION AT MID-OCEAN RIDGES WITH HIGH MAGMA SUPPLY: PERSPECTIVES FROM SEAFLOOR ESCARPMENTS AND ICELAND