南极布兰斯菲尔德海峡海磁异常和深部地质

文章导出了南半球ΔＴ表达式，测区约位于６３°Ｓ，故异常以正值为主，负异常在其南侧。以化极、匹配滤波等方法处理数据得深浅源异常。深源异常自北向南以正负相间的三个条带状异常分别对应着南设得兰群岛、布兰斯菲尔德海峡和南极半岛，浅源异常则对应着海峡南北缘的两条断裂。深部异常认为是磁性基底隆拗所致，因太平洋板块对南设得兰群岛的俯冲，那里深部基性成分多，故北部的深浅源异常幅值皆比南部的高。据浅源异常还识别出了与海峡延伸方向垂直的断裂，结合地貌、岩浆岩年龄及地震波速分布，进一步认为南极半岛地区可能发生过西向漂移。

MARINE MAGNETIC ANOMALIES AND DEEP GEOLOGY OF THE BRANSFIELD STRAIT,ANTARCTICA

The expression of ΔT in the Southern Hemisphere presented in this paper. The survey area is located in 63°S ,so where it is characterized by positive anomaly, and negative anomaly in the south. Data processed by reducing to pole and matched filtering, the deep and shallow source anomalies are obtained. Three deep source anomaly belts are related to South Shetland Islands, the Bransfield Strait and Antarctic Peninsula, the north and south belts are positive and negative one in the middle. The two shallow source anomaly belts are related to two faults in north and south edge of the Bransfield Strait. The deep source anomalies are referred to relief of the magnetic basement, because of subduction of the Pacific plate in the South Shetland Islands, where deep background is characterized by high basic composition and the value of deep and shallow source anomalies are higher than that in the south. The faults which are vertical to the trending of the Bransfield Strait are recognized by shallow source anomalies. According to the results of the research on the landform, rock ages and seismic velocity distribution, westward drift of the Antarctic Peninsula had probably happened in history.