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1 Meteorological Research Institute, Tsukuba, Ibaraki 305, Japan
2 Faculty of Science, Chiba University, Yayoi, Chiba 263, Japan
3 Beppu Geophysical Research Laboratory, Kyoto University, Beppu, Ohita 874, Japan
4 National Institute of Polar Research, 1-9-10 Kaga, Itabashi, Tokyo 173, Japan
Vector geomagnetic anomaly field data obtained in the West Enderby Basin. Strikes of two-dimensional magnetic structures at the positions of their boundaries were determined using these data. The magnetic strikes were divided into two groups based on structural change and magnetic polarity change. A change in structural trend occurred around 500 km off the Antarctic coast to the east of Gunnerus Ridge. Approximately NNE-SSW structural trends dominate in the northern portion of the study area. In contrast, in the southern part, structural trends range between NW-SE and NNW-SSE directions. The latter trend is dominant just seaward of the continental slope of Antarctica, and is almost perpendicular to the coastline. ENE-WSW and E-W magnetic anomaly lineation trends, possibly belonging to the Mesozoic magnetic anomaly lineation sequence, are also observed in the southern part. Therefore, we surmise that the NW-SE and NNW-SSE-trending structures east of Gunnerus Ridge correspond to fracture zones formed during Mesozoic time and reflect the initial Gondwana break-up trend.
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This 250-word extract was created in the absence of an abstract.
