GEOPHYSICAL SITE CHARACTERIZATION OF THE MCQUAT LAKE SYNFORM MARY RIVER DISTRICT, BAFFIN ISLAND CANADA

• Author / Creator

  Ferguson, Ryan M

• Arctic drilling programs are expensive and time consuming and deliver very little data regarding the local and regional geological structure. By performing multiple passive and active geophysical surveys, a better understanding of both local and regional geology can be determined. This thesis combines an airborne magnetic survey with a ground based gravity survey and four localized 2D seismic refraction surveys to perform a site analysis and characterization of a subsurface iron ore body to assist in outlining future exploration and mining goals. Seismic data processing was hindered by poor data quality as a result of a permafrosted surface layer. Strong surface waves propagated quickly through this layer, yielding seismic amplitudes stronger than both the first refraction arrivals and near surface reflections. Ground roll was mitigated using a combination of Ormsby trapezoidal filters, curvelet SVD filters, FK filtering and Radon transforms to improve first arrival amplitudes and selection. Resulting first arrivals were selected and combined with survey geometry to create tomographic and velocity models using Schlumberger VISTATM Seismic Suite and Optim SEISOPT 2DTM. Refraction tomography and velocity models were compared against magnetic and gravitational inversion models created using Oasis Montaj GeosoftTM and agreements between all datasets were found to be very strong. Potential high-grade zones identified by strong magnetic susceptibility also correlated with high density and high velocity areas. Velocities in both the VISTA and Optim model were higher than expected in deeper regions, an effect likely caused by poor surface static corrections and permafrost alteration of shallower layers. The overall ore body was found to be approximately 250 meters thick and trend east west. The ore body plunges westward at approximately 3 degrees and dips northward at approximately 70 degrees. A final model highlighting overburden thickness was created to determine future mining feasibility and found that the total overburden thickness in the region was a minimum of 80 meters.

• Subjects / Keywords

  • Gravity Inversion
  • Magnetic Inversion
  • Seismic Refraction
  • Mcquat Lake, Baffin Island

• Graduation date

  Spring 2018

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/R3MC8RX4D

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.