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Please join us for two Graduate student seminars this Friday January 26 starting at 3:30 pm in rm 155 Geology presented by Zoe Vestrum and Todd LeBlanc, MSc candidates

Posted on 2018-01-22 in Events
Jan 26, 2018

Please join us for two Graduate student seminars this Friday January 26 starting at 3:30 pm in rm 155 Geology presented by Zoe Vestrum and Todd LeBlanc, MSc candidates:

Computational Analysis of Two-Phase Corner-Flow:

An Analogy to Fluid Movement in the Upper Mantle Beneath the Mid-Ocean Ridge

Presented by Zoe Vestrum

Consider a fluid-saturated porous volume whose solid viscosity is dependent on porosity. When such a material is subjected to shear, the porosity will rearrange into stripes of high and low porosity known as compaction melt-bands. This study models this phenomenon using conservation of mass and force-balance laws. This model differs from previous work, using background flow and pressure instead of traditional boundary conditions.

Model data examples include: pure- and simple-shear stress on a square geometry and stresses on a complex geometry which emulate the mid-ocean ridge. The square geometry models agree with analytical, or expected solutions. The mid-ocean ridge model has bands form where the solid velocity changes from vertical to horizontal.

Modelling and Survey Results of In-mine Electromagnetics for Brine Layer Detection

Presented by Todd LeBlanc

Safe mine expansion has been an essential focus for potash mines in Saskatchewan over the years. One of the primary areas of care and attention has been mitigating the potential for sub-saturated brine inflow. The source of sub-saturated brine in-flows are anomalously porous geological layers above the mining horizon. In this project we are proposing, through computer modelling and in-mine surveying, the possibility of detecting the presence of these anomalous zones using geophysical electromagnetic methods.

Areas of increased brine-filled porosity in the salt are known to produce a conductive response to various geophysical techniques. However, what is not well known is if the same response is measurable in the carbonates. The time-domain electromagnetic (TEM) method has been selected for this investigation as it has a variety of benefits to it’s application, including higher resolution depth sounding capabilities (when compared with frequency-domain electromagnetics) and low-power requirements to excite geology on the other side of the salt layer (unlike direct current resistivity).

These anomalously porous geological features are outside of the norm, and their genesis is not perfectly understood. However, there has been found a geospatial link between areas of increased brine and the absence or partial destruction of overlying, younger evaporite members. One such area was the target of a time-domain electromagnetic survey that the author participated in as part of a Mitacs Accelerate program partnership with Potash Corporation of Saskatchewan Inc. (now called Nutrien) in the fall of 2017.