鲍威尔海盆的重磁场特征及其构造意义

鲍威尔海盆位于南极半岛东北和南奥克尼微大陆之间,是南半球典型的高纬度边缘海。通过搜集鲍威尔海盆的相关重磁资料、历史文献,以及总结前人的相关研究成果,介绍了鲍威尔海盆的重磁场基本特征以及张开历史。结果表明鲍威尔海盆中部存在着约NW30°方向倾斜的埋藏扩张中心,两侧残存基底高地,在靠近陆架边缘存在着裂谷海盆。根据线性的对称磁异常分布模式及年代的限定,鲍威尔海盆的扩张历史可以被重建为40 Ma的闭合期,29.7 Ma的断裂后期,27 Ma的中脊扩张时期。

GRAVITY AND MAGNETIC CHARACTERISTICS OF THE POWELL BASIN AND THEIR TECTONIC IMPLICATIONS

The Powell Basin is a typical high latitude marginal sea in the southern hemisphere, located between the northeast of Antarctic Peninsula and the South Orkney Microcontinent. Gravity and magnetic data, historical documents and the research products of tectonic evolution of the basin have been comprehensively collected in order to describe the characteristics of magnetic and gravity fields and the opening history of the basin. A buried spreading ridge is found in the middle of the Powell Basin, trending approximately in NW 30°. Residual basements can be found on both sides of the ridge. A rift basin occurs on the shelf margin. The symmetric linear magnetic anomalies and age dating data made us possible to reconstruct the history of the Powell Basin which consists of the closure stage (40 Ma), post-rifting stage (29.7 Ma) and mid ridge spreading stage (27 Ma).