南极布兰斯菲尔德海峡的地球物理场特征与构造发育史

本文分析了“海洋四号”船１９９１年在南极布兰斯菲尔德海峡所采集的地球物理资料。这里的地形地貌、重力异常和磁异常沿东方向呈条带状分布。海峡中的新生代沉积可分为两组沉积系：第一张裂沉积系和第二张裂沉积系。在布兰斯菲尔德海峡西北部,基底发生了断裂,基底断块沿断面下滑,因而在海峡中部形成基底半地堑。通过横穿南设得兰群岛、布兰斯菲尔德海峡和南极半岛的地壳剖面,我们用分层剪切模式解释了在张性应力作用下的岩石圈变形特征。

THE CHARACTERISTICS OF GEOPHYSICAL FIELD AND TECTONICAL EVOLUTION IN THE BRANSFIELD STRAIT

Having analysised the data collected by our survey ship"Ocean IV "in the Bransfield Strait in 1991,we recognized that the geomorphology,gravity and magnetic anomalies trending NE direction along bandings. The sediments in the Bransfield Strait can be subdivided into two sequences:the first rifting equence and the second rifting sequence.The basement was faulted into a half-graben in northwestern side of the Bransfield trough. Considering the crustal structure crossing the South Shetland Islands,the Bransfield Strait and the Antarctic Peninsula, we propse a two-phase rifting tectonic evolution model and a layered-shear model for the lithospheric deformation under the effects of extensional stress field.