Mapping McFaulds Lake 'Ring of Fire' crystalline basement architecture in Ontario, Canada from airborne gravity gradiometry (AGG) data using steerable filter and normalized-cut image segmentation

摘要

Two of the most important tasks of interpreting gravity or magnetic data over sedimentary basins are, (1) to extract lineaments which often reflect concealed structural elements such as faults, fractures and lithological contacts, and (2) to partition the crystalline basement into segmented blocks or domains that may reflect possible litho-tectonic terrane boundaries. These two tasks play a major role in oil and gas exploration because they provide pathway for their migration, accumulation and they may also enhance reservoir permeability effectiveness. Occasionally, these two tasks are accomplished by generating a suite of filtered map enhancements that are visually inspected by experienced interpreter to pick lineaments. In some cases an attempt is made to partition the crystalline basement into segmented blocks based on their gravity, magnetic or seismic signatures complemented by other geological information such as well logs. However, the process of picking lineaments and partitioning the basement into different blocks using conventional approach is tedious and time consuming, and to some extent subjective. Therefore, in this study we developed a new approach to automate and accelerate the process. This new approach is much faster, cost effective and is less subjective than the conventional approach. Furthermore, it is more suitable to process a large volume of data such as those acquired by marine and airborne geophysical surveys.