Geophysical investigation of northern Sulu UHPM terrane in east China (II): Non-seismic methods

Additional to deep seismic reflection survey[1]. MT; magnetic and gravity a s well as radioactivity surveys have been applied in the crustal investigat ion in the Sulu ultrahigh pressure metamorphic (UHPM) terrane. The results of these non-seismic methods well be introduced in this paper. Two regional profiles of total length 126km are obtained from 2-D inversions, producing electrical resistivity and geomagnetic sections. The results include that (1) in agree with deep reflection interpretation, MT and geomagnetic profil es show similar the subduction and exhumation pattern of the Sulu UHPM rock slice; (2) these data provide not only constraints to seismic interpretati on, also new evidences for heat flow uplifting, as well as existence of fau lts and geomagnetic bodies; (3) discovering a new fault of striking NNW, na med Junan-Haizhou fault, which is very significant to reveal the regional t ectonic evolution; (4) based on heat-flow uplifting, many granite intrusion s, deep buried high-velocity lens,it seem that the northern Sulu area is no t ideal site for deep scientific drilling project which aims revealing the mechanism of formation and exhumation of the UHPM slices. We will continue to present a paper involved in geophysical investigations in the southern S ulu UHPM terrane.