Geological Significance And Processing Of Gravity And Magnetic Data In The Northwest Of The West Philippine Basin

The West Philippine Basin is one of the oldest basins in the west Pacific margin, lying on the Philippine Sea Plate, with complex formation history.This thesis makes processing to many marine gravity and magnetic data, including data collected during KR03-04 cruise. Common result maps are gained, including contour map, continuation map and derivative map. Also, this thesis make processing and interoperation of three seismic profiles in this area, and two of them were made joint inversion with gravity and magnetic data.Form the above works, the tectonics trend NWW, with NE trending big zone. Three units are divided, Oki-Daito Ridge (ODR), Urdaneta Plateau (UP) and Okinawa-Luzon fault zone (OLF). The OLF break heavily, trending NE and converting to NNE off Ryukyu Trench (RT), and it is a very deep and large fault with right handed. It may be formed by blocking of Ryukyu Islands. There is also a fault between two plateaus of the UP, with NW trend. The ODR and UP may be remained arc. According to ODP and DSDP data, the cause and times of outer RT mountain ridge formation. Under it there is a broken basement, a powerful proof for amagmatic spread. The force may be the pull of subducted Philippine Sea Plate.