New magnetic anomaly map in East Asia

Magnetic data provides basic information for geologic and geophysical interpretation. From 2004 to 2010 we have collected 57 magnetic cruises by using different research vessels. In this study we attempt to compile the newly collected and existing magnetic data including land, marine and aeromagnetic data in East Asia area, which can provide us a general overview of the tectonic framework of the study area. Based on newly compiled map, several magnetic features can be identified in the new magnetic map. (1) The NE-SW trending high positive magnetic anomaly zone presenting in southwest Taiwan is still apparently. (2) A sharp boundary, named Zhongnan Fault, separates South China Sea into east and southwest sub-basin. The magnetic patterns in the southwest sub-basin differ from in east, not only in amplitude, but also in the trending of the spreading. (3) Between Gagua ridge and Luzon-Okinawa Fracture Zone, the magnetic lineations reveals NW-SE direction. This indicates that the spreading direction was NE-SW in this area. (4) Strong positive magnetic anomalies over the Taiwan-Sinzi, Yushan, Yandang, and Zhemin Ridges suggest the existence of remnant volcanic arcs. High positive magnetic anomalies located beneath Ryukyu arc and Ryukyu Trench implies a high magnetized material of the subducted Philippine Sea Plate.