Japanese-German joint airborne geophysical surveys around Syowa Station, Antarctica

• Main Authors: Nogi, Y., Steinhage, Daniel, Kitada, K., Riedel, Sven, Jokat, Wilfried, Shiraishi, K., Shibuya, K.
• Format: Conference Object
• Language: unknown
• Published: 2007
• Subjects: Antarctic; The Antarctic; Syowa Station; Antarctic Ocean; Lützow-Holm Bay; Shirase Glacier; Antarc*; Antarctica
• Online Access: https://epic.awi.de/id/eprint/16888/; https://epic.awi.de/id/eprint/16888/1/Nog2007a.pdf; https://hdl.handle.net/10013/epic.26727; https://hdl.handle.net/10013/epic.26727.d001

IntroductionThe evolution of Antarctica and the Antarctic Ocean is vital to understanding the growth and breakup of super continent Gondwana. The reconstruction models of Gondwana have been established by many authors using geophysical data set as well as geological data (e.g. Norton and Sclater, 1978). The area around Syowa Station, the Japanese Antarctic wintering Station in Lützow- Holm Bay, is considered to be a junction of Africa, India, Madagascar, and Antarctic continents from the reconstruction models of Gondwana. Therefore this area is a key to investigate the formation and fragmentation of Gondwana. However, the tectonic evolution is still speculative because geological evidence is limited to a few isolated outcrops and the coverage with geophysical surveys in this area is poor.Joint Japanese-German airborne geophysical surveys around Syowa Station had been conducted in January 2006 during the 47th Japanese Antarctic Research Expedition to reveal tectonic evolution of the area around Syowa Station. The observation lines are shown in Figure 1.Data The airborne geophysical surveys had been made along almost N-S observation lines with spacing of about 20 km. Ice radar measurements had been carried out onshore area and ice thickness data are obtained. Bed rock topography are estimated using RAMP surface elevation data set. Magnetic and gravity measurements had been conducted both onshore and offshore areas. Magnetic anomalies are determined after correcting diurnal geomagnetic variations at Syowa Station. Precise positions of the aircraft are determined using DGPS techniques and free-air gravity anomalies are also obtained. Those data are girded and plotted using GMT software (Wessel and Smith, 1998).ResultsThe results of bed rock topography, gravity and magnetic anomalies are shown in Figures 2, 3 and 4, respectively. Characteristic features possibly related to the tectonic evolution from the results are summarized as followings. Large negative gravity anomalies are observed along the Shirase Glacier (A ...