APPLICATION OF REGRESSION AND VARIANCE ANALYSES FOR GRAVIMETRY DATA INTERPRETATION

Abstract

The Purpose of the paper is to evaluate the possibilities of regression and variance analyses in the quantitative interpretation of gravity anomalies when solving gravity inversion problem in complex geological conditions. Methods. The paper considers the possibilities to use a factor analysis and singular matrix decomposition under the gravity field inversion of the Ulaanbaatar depression (Mongolia), which is characterized with a complex geological structure. Results. We have obtained the quantitative characteristics of the loose sediment thickness in the structure under investigation and the data on morphological features of the immersed part of the crystalline basement. The Ulaanbaator depression has a complicated block structure. The transverse uplift of the foundation divides it into two basins: Western and Central. In the Western part, which is the area of tectonic disturbances, the identified basin is oval in shape with the dimensions of 3×6 km and the thickness of the deposition lens of 100-120 meters. The maximum thickness of Cenozoic deposits in the Central basin is 130-160m. Obtained quantitative assessments are confirmed by the results of mathematical modeling under gravity field inversion of the studied basin with the help of analytical methods. Conclusions. The thickness of loose deposits has been estimated and the surface morphology of the Ulaanbaator depression basement has been described by means of regression and variance analyses under gravity field interpretation in complex geological conditions. The results of gravity field inversion by means of the considered mathematical tools coincide with the calculation results of the analytical methods when solving a one-dimensional inverse problem for a contact surface (for a flat layer), which confirms the efficiency of the proposed interpretation method of gravity anomalies.