Thompson Field Forums

Ontario and Québec, Canada | 23–30 August 2027

Application Deadline: 21 January 2027

DESCRIPTION AND OBJECTIVES

The deep continental crust is a crucial archive of the construction, differentiation, and stabilization of the continental crust. The geodynamic regimes that operated in the Precambrian are contentious, with Archean geodynamic end-members including modern-style subduction and plate tectonics to stagnant lid settings, and anomalous hot conditions in the Proterozoic. Northern Ontario and Southwestern Quebec in Canada provide ideal and accessible transects through deep crustal rocks from the Neoproterozoic to the Archean that are reflections of these times in Earth’s history. We will investigate the intimate relationships between ductile deformation, fluid infiltration, partial melting, and high temperature-metamorphism in diverse rock types (metapelitic to metabasic). This field forum is a timely opportunity to bring together international geoscientists to develop new collaborations and ideas relevant to high-profile topics in Precambrian geology and geodynamics using the metamorphic and igneous rock record from the deep crust.

Field Forum Highlights include:

1. Deep crustal exposures of Proterozoic and Archean rocks have variable tectonic/structural histories recording diverse metamorphic and igneous processes.
2. Investigating the metamorphism of deep crustal rocks (metasedimentary, metaigneous) and exploring the roles of fluid-aided versus fluid-absent partial melting in the deep continental crust.
3. Assessing source composition versus magmatic fractionation in controlling the composition of mid- to upper-crustal granitoid plutons.
4. Examining a rare and nearly complete section transitioning from the upper to lower continental crust in the Archean Superior Province and exploring the implications for mineralization systems.

LEADERS

Chris Yakymchuk, University of Waterloo, Canada

Manuel Duguet, Ontario Geological Survey, Canada

Jillian Kendrick, Saint Mary’s University, Canada

David Pattison, University of Calgary, Canada

AGENDA

This eight-day Thompson Field Forum will have participants meet in Toronto and travel through the Grenville Province, then through the Superior Province and end in Mont Tremblant (near Montreal, Quebec). We will visit outcrops that are representative of deep crustal processes in Proterozoic and Archean systems. August has moderate temperatures (5–20°C) during the day. No special fitness is required, and outcrops are easily accessible from the road or short hikes along trails adjacent to roadways.

Day 1 (23 August): Arrival in Toronto by 5 p.m. Overview of the geology of the Canadian Shield and group introductions. Overnight in Toronto.

Day 2 (24 August): Travel through the southwestern Grenville Province with stops dedicated to partial melting reactions in the deep crust (fluid-present and fluid-absent) in high-temperature gneiss terranes. Overnight in Parry Sound.

Day 3 (25 August): Investigate the relationships between ductile deformation and high-temperature metamorphism during development of the Grenville Front Tectonic Zone. Study of shatter cones of the Sudbury Impact Structure. Overnight in Sault Ste Marie.

Day 4 (26 August): Visits at scenic outcrops along the shore of Lake Superior. Overnight in Wawa.

Day 5 (27 August): Study of Archean Tonalite–Trondhjemite–Granodiorite (TTG) complexes and their deformed and metamorphosed equivalents. Overnight in Chapleau.

Day 6 (28 August): Exploration of the Kapuskasing uplift; spectacular mafic migmatites from the roots of Archean continental crust. Overnight in Timmins.

Day 7 (29 August): Investigation of Archean rocks, structures, alteration and mineralization along the world-renowned Abitibi gold belt. Overnight in Val d’Or (Quebec).

Day 8 (30 August): Travel across the Grenville Front Tectonic Zone investigating the interplay between ductile deformation and metamorphism in the deep crust. Trip ends in Mont Tremblant (Quebec) in time for the start of the Granulites & Granulites 2027 conference.

APPLICATIONS AND REGISTRATION

The registration fee of [US$500] covers lodging in hotels based on double occupancy. Breakfast, lunch, dinner, transportation and field trip guides are included. Single-occupancy rooms may be available for an additional fee.

Some international visitors to Canada may require visas and should check https://travel.gc.ca

for country-specific information. Participants should bring clothing appropriate for the weather, sturdy hiking shoes or boots, rain gear, insect repellant and sunscreen. Drinking water and snacks will be provided throughout the trip.

Some financial support may be available for students, early career scientists, and those with financial need to partially offset registration costs. GSA and the meeting conveners are committed to promoting diversity, equity, inclusion, and belonging within the geoscience community. We strongly encourage applications from individuals of all backgrounds, especially those from groups underrepresented in Earth sciences. Attendees are expected to honor the GSA Code of Conduct (https://www.geosociety.org/conduct).

LOGISTICS AND ATTENDEES

Application Deadline: 21 January 2027

Registration Deadline: 22 April 2027

Participants must commit to the full eight-day/seven-night field conference. Group size is limited to 32 participants. To apply, please complete the GSA Thompson Field Form 2027 Application. For questions, please contact thompsonfieldforum@geosociety.org.

Join Granulites & Granulites 2027 | 31 August – 2 September 2027

We encourage participants to continue onto the 6th offering of the Granulites & Granulites conference in Mont Tremblant, Quebec (31 Aug–2 Sept). This conference, hosted by the Mineralogical Society of the UK and Ireland, is an excellent opportunity to learn about leading-edge research in metamorphic systems and the deep crust and continue the discussion of key topics investigated during the Field Forum. Independent registration is required.

https://www.minersoc.org/granulites-and-granulites.html