Reykjanes Ridge evolution: Effects of plate kinematics, small-scale upper mantle convection and a regional mantle gradient
Reykjanes Ridge evolution: Effects of plate kinematics, small-scale upper mantle convection and a regional mantle gradient
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DOI：
10.1016/j.earscirev.2019.102956
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发表时间：
2020-07
影响因子：
12.1
通讯作者：
F. Martínez;R. Hey;Á. Höskuldsson
中科院分区：
文献类型：
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作者：
F. Martínez;R. Hey;Á. Höskuldsson
雷克雅未克海脊是研究区域地幔熔融异常上的板块边界过程的关键背景。海脊起源于一个脊-脊-脊三联点的一个分支，将格陵兰、欧亚大陆和北美洲分隔开来。它最初形成一个线性轴，以缓慢的速度正交扩展，没有转换断层或正交地壳分割。这种结构持续了1.18亿年的稳定扩张，直到拉布拉多海扩张停止，终止了格陵兰与北美的三重连接，并导致整个洋脊的开放方向发生了1.30 °的快速变化。海脊突然被一系列转换断层分割和抵消，这些断层似乎在长度和间距上朝着冰岛减少。在没有进一步改变开口方向的情况下，洋脊迅速开始从北向南系统地和历时地重新组合其原来的线性结构，尽管这需要洋脊在再次变成线性时倾斜扩展。突出的V形地壳脊从轴向外扩展，脊变成直线状。目前，从冰岛到Bight转换断层（距离近1000公里）的重新配置已接近完成。地幔柱和板块边界过程被认为控制了雷克雅内斯海脊的构造重构和地壳增生特征。在这里，我们回顾了脊的特征和构造演化和各种模式提出的影响他们。
The Reykjanes Ridge is a key setting to study plate boundary processes overlaid on a regional mantle melting anomaly. The ridge originated as one arm of a ridge-ridge-ridge triple junction that separated Greenland, Eurasia, and North America. It initially formed a linear axis, spreading orthogonally at slow rates without transform faults or orthogonal crustal segmentation. Stable spreading continued in this configuration for ∼18 Myr until Labrador Sea spreading ceased, terminating the triple junction by joining Greenland to North America and causing a rapid ∼30° change in opening direction across the ridge. The ridge abruptly became segmented and offset by a series of transform faults that appear to decrease in length and spacing toward Iceland. Without further changes in opening direction, the ridge promptly began to reassemble its original linear configuration systematically and diachronously from north to south, even though this required the ridge to spread obliquely as it became linear again. Prominent V-shaped crustal ridges spread outward from the axis as the ridge became linear. This reconfiguration is presently nearly complete from Iceland to the Bight transform fault, a distance of nearly 1000 km. Both mantle plume and plate boundary processes have been proposed to control the tectonic reconfigurations and crustal accretion characteristics of the Reykjanes Ridge. Here we review the ridge characteristics and tectonic evolution and various models proposed to influence them.