Three-component magnetic logging in the Louisville seamounts

点击翻译按钮获取中文摘要

From December 2010 to February 2011, an expedition of the international ocean drilling program (IODP) will be carried out to the Louisville seamounts, a submarine volcanic chain in the Pacific Ocean. In our project, we will analyse borehole magnetic measurements taken in the four boreholes of the expedition. The aim is to determine the remanent magnetization of the penetrated lavas, from which the geographic location at the time of the rock formation can be estimated. This provides important information on the possible motion of the Louisville hotspot, one of the main goals of the expedition. The measurements will be taken with the Göttingen borehole magnetometer, the only magnetometer worldwide equipped with fiber optic gyros. The gyros allow an accurate tool orientation and thus the determination of all three components of the magnetic field. The three-component data enable us to determine the direction, in particular the declination of the remanent magnetization, which constitutes an essential piece of information to reconstruct the Louisville hotspot motion. The achievement of a sufficient accuracy requires extensive calibration, numercial simulation and the improvement of correction methods and inversion routines.