A Magnetic Survey Of The MTJ(Mangatolu Triple Junction) Caldera On Lau Basin

A Magnetic Survey Of The MTJ(Mangatolu Triple Junction) Caldera On Lau Basin
곽준영; Won, J; 박찬홍; 고영탁; 김창환; 정의영; Yu, S
KIOST Author(s)
Ko, Youngtak(고영탁)
Publication Year
We have performed a magnetic survey to understand magnetic distribution and characteristics of the MTJ(Mangatolu Triple Junction) caldera. MTJ caldera(15°25′S, 174°00′W) is located between MTJ northeast extending branch which connects to the northeast Tonga trench[Wright et al, 2000] and the main line of Tofua volcanic arc. The caldera results from coupling between the crust of the Tonga microplate and the subducting Pacific plate[Macleod, 1996]. The MTJ is characterized severe deformation and neovolcanism[Parson and Tiffin, 1993], and has been reoriented during the Brunhes Chron[Zellmer et al, 2001]. Generally, low magnetization at crust is highly correlated with active hydrothermal vent field. The acidic and corrosive fluids that constitute marine hydrothermal vent systems can quickly alter or replace the iron-rich magnetic minerals, which reduce the magnetic remanence of the crustal rocks, in some cases to zero. Magnetic field data were observed by using high sensitivity proton magnetometer which is towed 300m behind the ship(R/V Onnuri). The data were first merged with the ship navigation. Then magnetic field was inverted for crustal magnetization using Parker[1974] inversion approach, which takes bathymetry into account assuming a constant layer thickness and then sufficient annihilator is added to magnetization solution to balance the positive and reverse polarity amplitudes. In this study, all inversions are calculated assuming a 500m source thickness.
Bibliographic Citation
2006 AGU Fall Meeting, pp.1, 2006
American Geophysical Union
American Geophysical Union
Related Researcher
Research Interests

marine geophysics,deep-sea minerals,해양지구물리,심해저광물자원

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