Direct measurement of magnetic reversal polarity boundaries in a cross‐section of oceanic crust
Direct measurement of magnetic reversal polarity boundaries in a cross‐section of oceanic crust
复制标题
直接测量洋壳横截面中的磁反转极性边界
DOI：
10.1029/98gl02752
复制
发表时间：
1998
影响因子：
5.2
通讯作者：
B. Wooding
中科院分区：
文献类型：
--
作者：
M. Tivey;H. Johnson;C. Fleutelot;S. Hussenoeder;R. M. Lawrence;C. Waters;B. Wooding
由潜水器进行的磁场测量确定了磁极反转边界的横截面几何形状和洋壳上部地壳磁化的垂直变化。测量的极性边界显示出一种系统的模式，即在上部喷出熔岩中向扩张轴方向浅倾斜，在下部喷出熔岩中倾斜较陡。这种几何形状是大洋中脊喷发出的熔岩侵位的结果。利用反转边界几何形状和磁化强度估计来计算喷出熔岩序列对上覆海洋磁异常信号的磁性贡献。从正演模拟来看，高磁化的喷出熔岩贡献了观测到的海面磁异常的大部分(50-75%)，这与形成年轻海洋磁异常的主要源层的喷出地壳相一致。
Magnetic field measurements made by submersible define the cross‐sectional geometry of a magnetic polarity reversal boundary and the vertical variation of crustal magnetization in upper oceanic crust. Measured polarity boundaries show a systematic pattern of shallow dip towards the spreading axis within the upper extrusive lavas, and steeper dip in the lower extrusive lavas. This geometry is a consequence of the emplacement of extrusive lava at a midocean ridge. Reversal boundary geometry and magnetization estimates are used to calculate the magnetic contribution of the extrusive lava sequence to the overlying marine magnetic anomaly signal. From the forward modeling, the highly magnetized extrusive lavas contribute the majority (50–75%) of the observed sea surface magnetic anomaly, consistent with the extrusive crust forming the primary source layer for young marine magnetic anomalies.