A STUDY ON SPECTRAL MOMENTS OF GRAVITY FIELD WITH APPLICATION TO CRUSTAL STRUCTURE IMAGING OF TARIM BASIN

Modern geophysical techniques provide great amount data of geophysical field that contain rich information about crustal structures, which can be extracted for geo-mapping based on theory of mathematical physics. This paper shows that the high-order spectral moments of regional gravity data include information of geometrical contour surface, which can be used for selection, positioning and classification of some types of geological structures. By using second-order spectral moments of Bouguer gravity data, one can calculate their statistical unvaried quantities and the ridge-like parameter, which characterizes the crustal deformation belts and can be used for mapping regional distribution of the deformation belts. The boundaries between areas of strong or weak ridge-like parameters represent boundaries of different structural units. We can further compute the second-order spectral moments of the statistical unvaried quantities to calculate the boundary parameter, which may be used for tracing and positioning the structural boundaries after some enhancement are added. This paper gives all the formula for computing the ridge and the boundary parameters, and testing results on crustal structural analysis in Tarim basin, Northwest China. As the results, deep High- and Low-density belts within the Tarim basin are located precisely, providing important basic images for oil/gas exploration in the basin.