KEGS Seminars - Three geophysics student presentations

   

This month there will be three student presentations, including our own Michael Cunningham and Jennifer Blanchard! Both students just successfully defended their M.Sc. theses.

 

There will be an organized canal skate after the meeting.
All are welcome!


Recent M.Sc. graduates Jennifer Blanchard and Michael Cunningham


Tuesday, February 9th
4:30 p.m.  

Gamble Hall
Geological Survey of Canada
615 Booth Street

 

First Speaker

Ambient noise interferometry in an
active underground mine environment

Philip Dales, University of Ottawa

 

Abstract

The mining of increasingly deeper ore bodies, where pressure conditions present high risks of rock instability, poses new geotechnical challenges. The ability to effectively monitor changing conditions of the rock mass is therefore essential for safe and productive mine operation. As stress in the rock mass can be inferred from seismic wave velocity, the challenge is to determine temporal variations in the 3D velocity structure encompassing the mine. Ambient noise interferometry could provide an effective solution to standard microseismic monitoring and involves the cross-correlation of ambient ground motion recordings between a pair of seismic receivers, with the resulting noise correlation function simulating the signal one receiver would measure from an impulse excitation at the other. This allows spatial resolution to be controlled by the distribution of sensors while temporal resolution depends on the length of noise recordings required to generate stable waveforms. From these waveforms it should be possible to precisely measure either absolute or relative travel-time variations to be used in a tomographic inversion scheme. This work focuses on what we believe to be the biggest challenge, obtaining stable and reliable noise correlation functions at a reasonable temporal resolution in the unfavourable noise conditions of an active underground mine.

 

Biography 

Philip is currently a Ph.D. student at the University of Ottawa . He gained work experience at Sander Geophysics.

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Second Speaker

Magnetic surveying with a rotary-wing UAS:
A case study of Nash Creek, NB

Michael Cunningham, Carleton University

 

Abstract

In the mineral exploration industry there has recently been a growing interest in the use of unmanned aircraft systems (UASs) for magnetic surveying. UASs are expected to provide higher resolution data as well as lower operational costs compared to traditional airborne systems. Some UASs also have the potential to shorten the exploration cycle by eliminating the need for ground surveying. This talk will feature one of these potential systems, the SkyLance rotary-wing UAS, as well as present results from a test survey performed over a known magnetic anomaly associated with a zinc-lead-silver deposit in Nash Creek, NB. Both ground magnetic and aeromagnetic data were collected and compared, where it was found that the SkyLance UAS provided repeatable, high-quality aeromagnetic survey data.

 

Biography 

Michael Cunningham is a recent M.Sc. graduate from Carleton University and he also holds a B.Sc. Hon. in Physics and a B.Sc. Hon. in Earth Sciences. Michael’s M.Sc. thesis is titled: “Aeromagnetic surveying with unmanned aircraft systems”. It was completed under the supervision of Dr. Claire Samson. During his time as a M.Sc. student Michael has been awarded the KEGS CGG airborne scholarship for two consecutive years.  He also won the Unmanned Systems Canada Student Papers Competition in 2015.

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Third Speaker

Gravity and magnetic potential field modelling
of mafic-ultramafic intrusions in the
Mackenzie and High Arctic Large Igneous Provinces

Jennifer Blanchard, Carleton University

 

Abstract

Mafic-ultramafic intrusions associated with LIPs have been linked to major Ni-Cu-PGE deposits (e.g. the PGE-Cu-Ni – bearing Norilsk-Talnakh intrusions linked with the Siberian Trap LIP). The focus of this presentation is to outline a protocol to identify mafic-ultramafic layered intrusions linked with LIPs and to identify potential areas for exploration. Gravity and magnetic data derived from the EGM2008 and EMAG2 datasets are used for a global survey of geophysical anomalies in 18 LIP plume centre regions, with the goal of identifying mafic-ultramafic intrusions linked to those LIPs. From these, we recognize three types of spatial distributions for intrusions in plume centre regions: 1) intrusions that circumscribe the plume centre emplaced along circular fault systems, 2) intrusions emplaced along linear rifts, in some cases rifts that converge towards the plume centre, and 3) single/unclassified intrusions. Joint inversion of gravity and magnetic data is done with 4 plume centre regions. I will be focusing on two Canadian examples: The first is given at the 1270 Ma Mackenzie LIP centered on Victoria Island, Northwest Territories, where we have confirmed the initial insights by Baragar et al. (1996) about a ring of intrusions circumscribing the Mackenzie plume centre.  The second is the 130 – 80 Ma High Arctic LIP (HALIP) with a plume centre located to the west of Ellesmere Island, Arctic Canada, where a prominent + 850 nT circular magnetic anomaly on the western coast of Ellesmere Island is interpreted to be the expression of a major mafic-ultramafic intrusion linked with the HALIP, and which modelling indicates is located at a depth of about 6 km. Furthermore, I will discuss how information about these deep-seated components of the plumbing system can be used to locate near-surface layered intrusions linked with LIPs.

 

Biography 

Jennifer recently graduated with a Master of Science, honored with distinction, from Carleton University in Earth Sciences. She obtained a Bachelor of Science from McGill University, Montreal, in Physics with a minor in Geology. While at Carleton she studied potential field signatures of Large Igneous Province (LIP) plumbing systems to identify and characterize associated layered intrusions within the plume centre region. She strongly believes in giving back to the earth sciences community as much as possible. During her time at Carleton, she participated in outreach activities such as Geoheritage Day, which consisted of educating the public to the local geology at various stations around Ottawa. She was also co-President of the OCUSEG executive committee (Ottawa - Carleton Universities Society of Economic Geology Student Chapter) from 2014-16, where events such as Career Day, geology field courses and various talks are organized for students at Carleton U. and U. of Ottawa. She was also a part of the AESRC committee (Advances in Earth Sciences Research Conference) for 2014-16, which is a conference jointly organized by U. of Ottawa, Carleton U. and Queens U. that allows students and guest speakers to present their research in the Earth Sciences in a friendly environment.