KEGS/BCGS Roundup Breakfast 2019

KEGS/BCGS Roundup Breakfast – Tuesday, January 29, 2019

Speaker: Dr. Glyn Williams-Jones, Centre for Natural Hazards Research, Department of Earth Sciences, Simon Fraser University

Title: Mt. Meager volcano – a complex and active multi-hazard system

Date/Time: 2019-01-29 @ 7:30am – 9:00am

Location: Princess Louisa Room, The Fairmont Waterfront Hotel
900 Canada Place, Vancouver, BC V6C 3L5

Registration: Online at www.kegsonline.org (Deadline Jan 27, 2019)

Abstract:

Climate change is causing the retreat of glaciers throughout the Canadian Cordillera, including at volcanoes. Glacial retreat can lead to unloading at the base of steep slopes, which coupled with the often wide spread hydrothermal alteration of volcanic massifs, can facilitate large landslides capable of traveling tens of kilometres and impacting population centres and infrastructure. Increasing summer temperatures can further heighten snowmelt that is capable of infiltrating slopes and triggering landslides.

The Mount Meager Volcanic Complex (MMVC), a large volcanic system located 65 km northwest of Pemberton, BC, is the site of long-lived volcanic activity. Mt. Meager was the site of Canada’s largest recent explosive event, ~ 2430 years ago, with the eruption of 0.8 km3 of material sending ash 530 km east to Calgary. It currently hosts actively degassing fumaroles that have formed melt caves in the Job Glacier on the northern flank of massif. The long-lived activity of Mt. Meager has also made it the target of extensive geothermal energy exploration and important nearby infrastructure exists in the form a run-of-river hydroelectric project on the upper Lillooet river.

Importantly, Mt. Meager is the also site of Canada’s largest historic landslide in 2010 with a total failure volume of 53 ± 4 x 106 m3. Field mapping and terrain analysis suggests that it was likely weakened due to substantial changes in the hydrological system associated with loss of glacier ice (~1.3 km3 of ice loss since 1987). Continued InSAR monitoring has identified numerous hydrothermally altered slopes (27 at >5 x 105 m2) that are actively deforming; some of these slopes are moving at up to 36 ± 10 mm per month during the summer and have volumes > 300-500 x 106 m3. As such, there is a significant and imminent threat to infrastructure and communities downstream.

This talk will present an overview of the volcanic history, ongoing and future research projects as well as the current status, geohazards and new monitoring initiatives on the Mt. Meager Volcanic Complex.

About the Author:

Dr. Glyn Williams-Jones,

B.Sc. U. Montréal, 1994; M.Sc. U. Montréal, 1997; Ph.D. Open University (UK), 2001; Postdoc U. Hawaii Manoa, 2003.

Glyn is a Professor in the Department of Earth Sciences at Simon Fraser University and co-Director of the Centre for Natural Hazards Research. The Centre for Natural Hazards Research has a broad mandate to conduct innovative training and research on geophysical processes that are a threat to the population and economic infrastructure of Canada.

Glyn is a physical volcanologist whose multidisciplinary research involves geochemical and geophysical modelling in conjunction with terrestrial and satellite remote sensing to investigate the processes responsible for triggering volcanic eruptions as well those controlling persistently active volcanism. The principal focus of his research is the investigation through active monitoring and retrospective studies of the interaction between the intruding magma and that already residing in the reservoir. The goal of this work is to gain insight into the precursory signals of volcanic activity and the mechanisms that trigger volcanic eruptions.

EAGE Short Course: Gravity and Magnetic Methods for Mineral Exploration – CANCELLED

Gravity and Magnetic Methods for Mineral Exploration, Dr. Yaoguo Li.

October 30, 2018.
We received the unfortunate news overnight that the EAGE has to cancel the gravity/magnetics workshop by Dr. Yaoguo Li on December 13th. On behalf of the BCGS, I thoroughly apologize for this shortcoming right after we announced the event.
We hope we will see you at future BCGS events and technical talk meetings.
Sincerely, BCGS Executive

 

Presented by EAGE and hosted by the BC Geophysical Society.

This 1-day workshop covers the concepts and methodologies of gravity, gravity gradiometry, and magnetic surveys. This course will focus on the methodology, numerical computation, solution strategy, and applications of 3D physical property inversions of gravity and magnetic data sets.

Course Flyer: EAGE Short Course Flyer

Date: Thursday, December 13, 2018
Time 8:00 am to 5:00 pm PST
Registration Cost:
– Early Bird Price $115 CAD
– EAGE Member Price $85 USD (~111 CAD)
– Non-EAGE Member Price $175 USD (~$230 CAD)
– Student EAGE Member Price $60 USD (~$78 CAD)
– Student Non-EAGE Member Price $145 USD (~$190 CAD)
Prices converted to CAD are approximate.
Location: BCIT Downtown Campus, 555 Seymour Street, Vancouver BC, V6B 3H6

PRE-REGISTRATION NOW AVAILABLE
Email info@bcgsonline.org
to secure your spot for only CAD 115
Only ten early-bird spots available!

Click on the link for the EAGE course page. EET11 – Gravity and Magnetic Methods

Course Outline
Part-I: Common concepts and methodologies
Fundamentals of potential-field data observed in gravity, gravity gradiometry, and magnetic surveys
Data processing methods based on equivalent source technique and inverse formulation
3D gravity and magnetic inversions and the practical strategies for their efficient solution and applications to large-scale problems
Binary inversion potential-field data in 3D
Gravity gradiometry

Part-II: Mineral exploration
Inversion and interpretation of magnetic data affected by remanent magnetization
Case histories from mineral exploration

Participants’ profile
We anticipate the geoscientists in the following areas will benefit from the course:
Potential-field methods
Mineral exploration
Integrate interpretation
Reservoir monitoring
Groundwater hydrology

Prerequisites
Participants are expected to have basic background in applied geophysics and some knowledge of potential-field methods.

 

YaoguoLi_HeadShotYaoguo Li received his B.Sc. in geophysics from the Wuhan College of Geology (currently China University of Geosciences) in 1983, and a Ph.D. in geophysics from the University of British Columbia in 1992. He worked with the UBC-Geophysical Inversion Facility at UBC from 1992 to 1999, first as a Post-doctoral Fellow and then as a Research Associate. He is currently an Associate Professor of Geophysics at the Colorado School of Mines and leads the Center for Gravity, Electrical, and Magnetic Studies (CGEM) and the Gravity and Magnetics Research Consortium (GMRC). He is a co-recipient of the 1999 Gerald W. Hohmann Award, SERDP 2007 Project of the Year Award, and 2010 ASEG-PESA Laric Hawkins Award. His research interests include inverse theory; inversion of gravity, magnetic, and electrical & EM data arising from applied geophysics; and their application to resource exploration, environmental, and geotechnical problems. He has been doing research in these areas and has developed or co-developed a number of program libraries for inverting different types of geophysical data. These include DCIP2D, DCIP3D, GRAV3D, MAG3D, GG3D, BININV3D, and AMP3D.

BCGS 2018 Fall Symposium: Geophysics for Mineral Systems Thinking – Registration Open!

BCGS-Geoscience_LogosThe BC Geophysical Society and Geoscience BC are proud to present the 2018 BCGS Fall Symposium “Geophysics for Mineral Systems Thinking”

Many world-class mineral deposits are known to lie above geophysical and geochemical anomalies in the lithospheric mantle. The new paradigm in mineral exploration for such large-scale deposits, driven primarily by the Australian experience, is to image the whole lithosphere looking for those geophysical and geochemical anomalies and in particular to map the fluid pathways through which mantle derived fluids pass upwards through the crust. This approach, of mapping the whole mineral system, is one that leads very effectively to discovery of significant deposits through developing understanding of the whole system. In this new paradigm large-scale geophysics has a crucial role to play in the identification and definition of geologic systems on a regional scale, which can have an enhanced expectation of being the location of resources:  minerals, petroleum, diamonds and geothermal.

Date: Friday, October 12, 2018
Time 8:00 am to 5:00 pm PST
Registration Cost:
– Non-Member Price $150
– Member Price $130
– Student Price $30
Registration link is below
Location: BCIT Downtown Campus, 555 Seymour Street, Vancouver BC, V6B 3H6

Symposium Schedule: BCGS 2018 Fall Symposium Schedule

Symposium Abstract Booklet: BCGS 2018 Fall Symposium Abstracts

Please register in advance of the symposium. Your registration can only be guaranteed once payment has been received. The attendee name must be entered for registration to be complete.

 

Thank you for your strong support. We have sold out! Registration is now closed.

 

Co-Chairs: Joel Jansen, Anglo American and Alan Jones, Complete MT Solutions

Introduction By: Gavin Dirom, President and CEO, Geoscience BC

Speakers:

Katherine Boggs, Mount Royal University – From LITHOPROBE through EarthScope to the new pan-Canadian EON-ROSE Research Initiatives; Geologic Implications for Mineral Exploration across North America

Fred Cook, University of Calgary (emeritus) – Geophysical, Geochemical and Geological Targeting Potential Mineral Deposits: From Lithospheric Scale to a 5-cm Drill Core

Fiona Ann Darbyshire, Université du Québec à Montréal – Regional-scale natural-source seismology and the cratonic lithosphere

David Eaton, University of Calgary – Tectonic architecture in the Canadian Cordillera: Potential insights from CCArray seismological studies

Randy Enkin, GSC-Pacific, NRCan – Petrophysics for Mineral Exploration: Linking Geophysics and Alteration Geology

Alan Jones, Complete MT Solutions  – Keynote: Mineral systems mapping using magnetotellurics: Examples from Canada and Australia

Henry Lyatsky, Exploration Consultant – Exploration Uses of Regional Gravity and Magnetic Data: Examples from Province-Scale Work in Alberta

Ben Murphy, Oregon State University – How Long-Period EarthScope MT Data Might Inform Targeted Mineral Exploration in the Central United States

Andrew Schaeffer , GSC-Pacific, NRCan – Probing the diamond potential of the North American Lithosphere using seismic tomography

Adam Schultz, Oregon State University – Detailed studies of geothermal and volcanic systems by combining EarthScope long-period MT USArray data with higher-resolution wideband MT arrays embedded in the larger array

Richard Smith, Laurentian University – Geophysical exploration for mineral systems: highlights from the NSERC-CMIC Footprints Project and CFREF Metal Earth Project

Martyn Unsworth, University of Alberta – Lithospheric resistivity structure of Western Canada from long-period magnetotelluric data

 

March 2018 – Technical Talk

BCGS Technical Talk – March 15, 2018

Speaker: Obone Sepato, Anglo American

Title: Density and magnetic susceptibility data of the Bushveld Complex, South Africa

Date/Time: Wednesday, March 15, 2018 @ 4:30pm PST

Location: 4th Floor Conference Room, Room 451, 409 Granville St. (UK Building at Granville and Hastings), Vancouver

Abstract:

The Bushveld Complex (BC) is the largest known layered intrusion. This suite of rock crop out in northern South Africa to form the Western, Eastern and Northern Limbs. Most research carried out focuses on the mineralized horizons in the Rustenburg Layered Suite (RLS) of the BC. This study presents a large database of wireline geophysical logs across a substantive part of the stratigraphy of the RLS of the West- and Eastern Limbs. These consist of density and magnetic susceptibility datasets sampled at 1 cm. The major lithologies of the RLS intersected in the boreholes presented are gabbro, gabbronorite, pyroxenite, norite and anorthosite whose density histograms reveal that they are predominantly normally distributed, with density averages of 2.86-3.2 g/cm3. The magnetic susceptibility for these lithologies has a large variation from 10-7 to 13.2 SI with distributions that are multi-modal and asymmetric, which is typical of large layered mafic intrusions. Cross-correlation plots between density and magnetic susceptibility for several boreholes show that the above-mentioned lithologies form clusters (circular to elliptical), which typically overlap. This has been further investigated using k-means classification, to automatically detect these to create a semi-automatic lithology logging system, which has been particularly successful in boreholes from the Eastern Limb.

The final analysis carried out was using wavelet analysis across individual locations in the BC. This has revealed multi-scale cyclicity in all of the boreholes studied, which is attributed to subtle layering created by variations in modal proportions between plagioclase and pyroxene. In addition to this, since layering is generally ubiquitous across layered intrusions, this cyclicity can be assumed to be present across the entire BC. This technique may become increasingly important should the cyclicity in physical property data correlate with reversals in fractionation (demonstrated in the Northern Limb thus far) trends since this may suggest zones of magma addition, challenging the current perspective of four major magma additions as opposed to smaller periodic influxes of magma for the creation of this intrusion.

February 2018 – Technical Talk

BCGS Technical Talk – February 28, 2018

Speaker: Mike Dentith, Centre for Exploration Targeting, The University of Western Australia

Title: The Implications of the Mineral Systems Concept for Geophysical Exploration: A Perspective

Date/Time: Wednesday, February 28, 2018 @ 5:00pm PST

Location: 4th Floor Conference Room, Room 451, 409 Granville St. (UK Building at Granville and Hastings), Vancouver

About the Author:

Prof Mike Dentith is Professor of Geophysics at The University of Western Australia and a research theme leader in the Centre for Exploration Targeting (CET).  He has 25 years experience researching, teaching and consulting in mineral exploration geophysics.  He is editor of two case study ‘geophysical signatures’ publications on Australian mineral deposits and co-author of the textbook ‘Mineral Exploration Geophysics for Geoscientists’ published by Cambridge University Press.

Abstract:

The Implications of the Mineral Systems Concept for Geophysical Exploration: A Perspective

Mike Dentith, Centre for Exploration Targeting, The University of Western Australia

A mineral system is defined as “… all geological factors that control the generation and preservation of mineral deposits”. Most authors describe a mineral system as comprising a source of metals and/or ligands, a pathway along which fluids transport the metals to a location where they are concentrated (physical trap) and precipitated (chemical trap).

The mineral system concept has two main implications for geophysical exploration practices: the definition of additional types of targets at the district and larger scale (metal source region, fluid flow path, fluid reservoir), and the need to provide information over the full extent of the mineral system, i.e. larger areas and in particular to greater depths than is currently normal exploration practice.  At the same time the mineral system concept draws attention to the need for a better understanding of the petrophysical consequences of fluid-related alteration.

Where metal-bearing fluids are sourced in the lower crust or mantle it is possible that the processes that create the fluids, or the preferential removal of certain components of the rocks, cause changes to the physical properties of the rocks.    For example, depleted mantle may be different from primitive mantle, as may be mantle that has been re-fertilised via metasomatism.  Targeting the fluid flow path(s) is also a possibility, but may critically depend on the nature of the fluid flow.  If fluid flow is concentrated along a relatively small number of major faults then these comprise very difficult targets given they are expected to be relatively narrow and at significant depths.  Since they are expected to be shallower, the fluid flow pathways post-deposition of metals are a potential target.  If fluid flow is distributed (which may equate to focussed flow at a scale that cannot be resolved) in the lower crust then the associated alteration is another possible target.  However, the most attractive target which emerges from the mineral systems concept, as described by McCuaig and Hronsky (2014), is the postulated reservoir that contains high pressure metal-bearing fluid which is subsequently rapidly emptied causing concentrated fluid flow and metal deposition.  With dimensions measured in kilometres at depths of a few kilometres these are much more attractive targets than fluid flow paths.  Such reservoirs are potential targets at a camp/district scale that are needed to fill the ‘gap’ between prospect-scale targets (mineralisation, alteration) and regional/terrane-scale targets (major linears, suture zones).

Successful identification of the kinds of targets described above requires the petrophysical properties of alteration to be understood.  As noted by Witherly (2014) there is little known about this.  An exception is serpentinisation.  The available data, nearly all collected as part of academic studies of ophiolites and ocean crust, demonstrates how important a process this is.  The difference in density and magnetic properties between fresh mafic/ultramafic rocks and fully serpentinised equivalents encompasses the entire range of the common rock types.  Serpentinisation also affects electrical properties, albeit probably to a lesser degree, and potentially also electrical polarisation (due to the creation of magnetite) and dielectric properties due to the involvement of water in serpentinisation reactions.  The petrophysical consequences of other forms of common deposit-related alteration are virtually unstudied in a systematic fashion, although it is intuitively obvious that processes such as silicification will significantly affect electrical properties and talc-carbonate alteration will significantly affect density.

The large size and depth extent of most proposed mineral systems, compared to that of a mineral deposit, requires deep penetrating geophysical methods to detect features of exploration significance.  This has led to increased numbers of deep penetrating geophysical surveys such as magnetotelluric (MT) and passive seismic surveys, often funded by Government’s seeking to encourage exploration within their jurisdictions.  Deep seismic reflection surveys are too expensive to be widely used in this way.  MT surveys have the great advantage of being comparatively cheap  and with the widespread availability of 3D inversion codes and the super computers required to run them the resulting sub-surface conductivity distributions are much more ‘interpretable’ due to reduction in artefacts and more accurate representation of actual source geometries.  The weakness of the method remains its poor resolution and the very limited understanding of causes of conductivity variations in the deep crust and to a lesser extent the mantle.  Passive seismic methods, i.e. those that use natural sources of seismic energy, are also comparatively cheap but require deployment of equipment for periods of months to a few years.  Ambient noise and teleseismic body-wave tomography can map major crustal and mantle boundaries.  The final product is a data volume, usually of seismic wave speed, and these can make a useful contribution to minerals system analysis at the largest scales.  Another potentially significant development in passive seismic techniques is in receiver-function based methods.  Traditionally used to determine crustal thickness and Moho character (sharp, diffuse) the development of common-conversion-point based processing has allowed closely spaced (few kms) recordings to be combined with the resulting product resembling a low-resolution seismic reflection section.

Deep seismic and MT surveys can in principle, detect broad zones of alteration associated with metal-bearing fluid sources, pathways and reservoirs indicative of the presence of a mineral system.  A programme of trial surveys, comprising MT, receiver function and wide-angle seismic surveys across selected deposit camps/mineralised terrains and also unmineralised areas in Western Australia is on-going.  A parallel line of research aims to better understand the petrophysical consequences of fluid-related alteration processes and hence predict the geophysical responses of the various components of a mineral system.