News

Researchers from EOAS analyzed honey from beehives in six Metro Vancouver neighborhoods to test its potential as an urban biomonitor. Since honey bees typically forage within a two- to three-kilometre radius of their hives, honey can provide a geochemical “snapshot” of the local environment.  The study – the first of its kind in North America – was published last week in Nature Sustainability.

The study involves 5 researchers from EOAS, including Kate Smith, Dominique Weis, Marg Amini, Vivian Lai and Kathy Gordon, as well as former EOAS PhD student Alyssa Shiel (now Assistant Professor at OSU).  Analyses were carried out at UBC’s Pacific Centre for Isotopic and Geochemical Research.

The researchers found that the honey in Vancouver is extremely clean, well below the worldwide average for heavy metals like lead.  However, they found that the concentration of elements was higher in honey from areas with heavy traffic, higher urban density and industrial activity. They also compared the lead isotopic compositions of the honey to those from other local environmental samples including lichen, trees, rocks, and sediment. They discovered that the lead “fingerprints” of the honey did not match any local, naturally-occurring lead and instead pointed to potential manmade sources of lead.

The research team has been featured on numerous tv and radio broadcasts for local stations including Global BC, CityNews, OMNI and CKNW.  Their work has also captured the attention of the international media, with articles published by news outlets as far away as India, China and Spain. Highlights so far include coverage by the New York Times, BBC, National Geographic and Canadian Geographic.

The four-year study provides a present-day baseline against which future changes in Metro Vancouver’s environment can be compared as the city grows.  It may also serve as a useful model for other cities around the world, particularly where environmental monitoring infrastructure is currently not available.  Lastly, this study represents a successful example of community collaboration, benefitting from aspects of ‘citizen science’ as well as a partnership with Hives for Humanity, a local non-profit that creates opportunities for people to engage in the therapeutic culture that surrounds the hive.

Additional links:

UBC Press Release: https://science.ubc.ca/news/honey-bees-can-help-monitor-pollution-cities

YouTube video: https://youtu.be/sKkEF1KdPM4

Hannah McSorley is an MSc student in EOAS was a featured member for the  NSERC Strategic Network Projec "forWater".

Be sure to check out it out! http://www.forwater.ca/hannah-mcsorley.html

EOAS student, Andrew Steiner, just won the Mary Claire Ward Geoscience Award for 2019 (https://www.pdac.ca/members/students/awards/mcw)

The Mary-Claire Ward Geoscience Award was created to honour the memory of Ms. Ward. The intent of the award is to encourage and support a graduate student in Canada whose thesis is likely to increase our knowledge of the geological history of Canada through mapping.

The award, comprising $5,000 and a certificate, is given annually and honours the memory of Mary-Claire Ward who died in 2004. At the time of her death Mrs. Ward was the chair of the PDAC’s geoscience committee, chairman of Watts Griffis McOuat Ltd., and a past president of the Geological Association of Canada. She was a passionate advocate for the geosciences in Canada.

The award is administered by the Geological Association of Canada (GAC), the Prospectors & Developers Association of Canada (PDAC), the National Geological Surveys Committee, the Canadian Geological Foundation, and Watts, Griffis and McOuat Ltd.

The following summary of Andrew’s project is highlighted on the award website:

Andrew’s research aims to map auriferous fluid pathways, identify the salient geological controls on fluid flow and assess the physiochemical evolution of ore fluids in the CTGDs (Carlin-type gold-deposits) of the Nadaleen trend, Yukon. Detailed geology maps of the deposit and surrounding areas were made, and a comprehensive structural study was undertaken. Ore fluid pathways were interpreted within this geological framework to establish the timing of Au-mineralization relative to deformation events and to assess the significance of potential geologic controls on fluid flow. 

Congratulations to Catherine Johnson who has been honoured with the Shen Kuo Award for Interdisciplinary Achievements from the International Association of Geomagnetism and Aeronomy!

Catherine was cited for her interdisciplinary contributions that target a holistic understanding of bodies throughout the solar system, particularly the magnetic field of the planet Mercury, and the Earth’s magnetic field within the past five million years.

The award ceremony will take place this July at the IUGG General Assembly in Montreal.

Why subduction zones form

The outer, rigid shell of the Earth is broken into 60-200 km thick tectonic plates that move along each other along large fault zones, causing most of Earth’s earthquakes. The most violent of plate boundaries are subduction zones, where one plate dives below another, back into earth’s interior. Once active, subduction zones can exist for tens or even hundreds of millions of years, but how do they form?

An international team of earth scientists from Canada, the Netherlands, Norway, and the UK now showed for the first time that subduction zones form because plate tectonic changes elsewhere start pushing one plate below another. Previously, it was widely assumed that subduction zones form spontaneously because of gravitational instability. 

The widely accepted idea of how subduction zones form suggested that a piece of plate started to spontaneously sink into the mantle. This, then, creates a gap at the Earth surface that becomes filled with magma producing new, young crust. Only after millions of years would the sinking plate become heavy enough to start pulling the plates together, creating horizontal plate motion and regular subduction.

The study’s lead author Carl Guilmette of Laval University, Quebec, Canada explains: 'there are rocks on earth that we think formed in the early stages of a subduction zone. Such rocks are for instance found in Oman, where most rocks formed by filling a gap with new crust next to a new subduction zone, and some formed right at the subduction interface. Previously, we could only date when the rocks of the new crust formed and assumed that this occurred simultaneously with the first formation of a subduction zone’. Matthijs Smit, a dating specialist at the University of British Columbia, Canada, and co-author of the study, now managed to also date the formation of the rocks at the subduction interface. “We show that they are at least 8 million years older than the age of the crust that filled the gap. This means that horizontal plate motion came first, and the formation of the gap came later as a result, and not as a cause, of subduction”. 

Douwe van Hinsbergen of Utrecht University, the Netherlands, explains that the new result has major implications for our understanding of plate tectonics. “For the first time, we unequivocally demonstrate that subduction zones form because of changes in plate motion elsewhere. This means that changes in motion between two plates may have unexpected effects across the planet, including the formation of new subduction zones. Focus of follow-up research is now on which processes exactly drove the formation of the subduction zone that existed in Oman, but we may be searching across the planet”.

This discovery will be reported in Nature Geoscience on August 27th. Link:

https://www.nature.com/articles/s41561-018-0209-2

Abstract:

word-spacing:0px">Subduction zones are unique to Earth and fundamental in its evolution, yet we still know little on the causes and mechanisms of their initiation. Numerical models show that far-field forcing may cause subduction initiation at weak pre-existing structures, while inferences from modern subduction zones suggest initiation through spontaneous lithospheric gravitational collapse. For both endmembers, the timing of subduction inception corresponds to initial lower plate burial, whereas coeval or delayed extension in the upper plate are diagnostic of spontaneous or forced subduction initiation, respectively. In modern systems, the earliest extension-related upper plate rocks are found in forearcs, but lower plate rocks that recorded initial burial have been subducted and are inaccessible. Here we investigate a fossil system, the archetypal Semail ophiolite of Oman, which exposes both lower and upper plate relics of incipient subduction stages. We show with Lu-Hf and U-Pb geochronology of lower and upper plate material that initial burial of the lower plate occurred before 104 Ma, predating upper plate extension and formation of Semail oceanic crust by at least 8 Myr. Such a time lag reveals far-field forced subduction initiation and provides for the first time unequivocal, direct evidence for a subduction initiation mechanism in the geological record.

Evelyn Freres won the Data Speaks! storytelling competition at the Resources for Future Generations (RFG) conference in Vancouver last week (June 16-21).  Students were challenged to reimagine their research with a non-specialist audience in mind, and were judged on the accessibility of their research, their reasoning and their creativity.

Evelyn’s original abstract title “Can you really trust your neodymium isotopic ratios?” was revised to “Do you trust your data?”  In her video, Evelyn explains that her research aims to discover the limitations to acquiring precise and accurate data, which will in turn help other researchers “understand our planet in the best possible way.”

Link to Evelyn’s video: https://www.youtube.com/watch?v=bInUp8CA18g&t=9s

For more information, check out this link: https://pcigr.eos.ubc.ca/pcigr-phd-student-evelyn-freres-wins-rfg-2018-…