Lineament analysis as a tool for hydrocarbon and mineral exploration: a Canadian case study

Summary

An understanding of the geological framework and localized structural constraints are critical to hydrocarbon and mineral deposit exploration. Lineament tectonics has been used successfully to delineate global oil and ore deposits. Automated lineament routines are important to promote efficiency and consistency. We suggest an alternative approach to geophysical numerical methods. “Stream flow analysis” is commonly applied to topographic data to delineate stream locations, flow impact, and flow direction by identifying localized low points and their continuity on a topographic surface. In this study, we apply stream flow analysis to a “topographic” surface defined by aeromagnetic data, where faults and fractures are revealed since they are represented by magnetic lows. Conversely, magnetically high features, such as dykes, are delineated by changing the data set background value causing highs to be represented by lows. Furthermore, by constraining the dimensions of the “watershed” we are able to isolate linear features at multiple scales. Further analysis of stream segments involves direction /length studies, linearity analysis, and stream intersection points. Typically, geologic terranes will have a dominant fabric or fracture orientation due to the local tectonic history. Therefore if the linear directions are isolated along specific orientations, different geologic terranes are resolved. Ore deposits often occur along fracture systems since they act as a conduit for hydrothermal fluids. When multiple fractures culminate at a common intersection, the probability of mineralization increases. Thus, visualization of “stream intersection” points in conjunction with geophysical products will highlight exploration areas. These methodologies are applied to a study area in the Northwest Territories, Canada which has been shown to have high mineral potential and similar IOCG-type deposits as Olympic Dam in Australia.

Key words::

• lineaments
• magnetics
• topography
• mineral exploration
• IOCG