Abstract:

The study contrasted and analyzed magnetic susceptibility data obtained by well logging and core measurements from 100 to 2,000 m in the main hole of Chinese Continental Scientific Drilling (CCSD), the results were coherent. The statistical results of ultra-high pressure (UHP) metamorphic rocks- logging susceptibility indicated that the susceptibility  became low gradually from serpentinite to quartz eclogite, rutile-bearing eclogite, orthogneiss, retrograded eclogite, phengite eclogite, paragneiss, chlorite amphibolite and amphibolite.Magnetic anomaly △B_Z、△B_H and △B_T were computed from the data of tricomponent magnetic survey from 100 to 2,000 m in CCSD main hole. According to  the previous petrologic research, it was shown that  the magnetic anomaly in 530575 m was induced by magnetite, rutile, titano-magnetite, and the magnetic anomalies in 610640 m and 655680 m were induced by serpentinized peridotite, and that magnetic anomalies were dominated mainly by rock's susceptibility, and rocks which had high susceptibility displayed clear anomalies in the borehole.

Key words: Chinese Continental Scientific Drilling (CCSD), ultra-high pressure (UHP) metamorphic rock, well logging, magnetic susceptibility, magnetic tricomponent