GAC-MAC 2021 Field trips

GAC-MAC London 2021 is offering five field trips; four that will run virtually and one that will run virtually (pre-meeting) and in-person (post-meeting). Conference participants will have the option to take part in visiting: 

1)The Crawford Lake Conservation Area where varves made of light inorganic and dark organic couplets accumulate annually in a deep karstic basin on the NiagaraEscarpment; this is one of a dozen sites under consideration as the type section to define the proposed Anthropocene Epoch, with evidence of pre-Anthropocene anthropogenic impact in the reconstructed Iroquoian village in its small watershed.

2) The geological wonders of the Niagara Escarpment in the Hamilton area, including the sediments, fossils, and lateral changes in lithological characteristics that have been affected by continuous erosion;

3) The 1140 to 1105 Ma volcanic and intrusive rocks of the Early Midcontinent Rift from the spectacular Lake Superior shoreline to as far east as Timmins (virtual only), including “visits” to dykes, interlayered alkaline and tholeiitic basalt, and alkaline rocks of the Coldwell Complex;

4) The well-preserved outcrops of the Paleoproterozoic Huronian Supergroup, including evidence of early life, glacial activity, and effects of the Sudbury meteorite impact; this trip is dedicated to the memory of Grant Young;

5) The Arkona area paleoenvironment, an informative field trip for earth science educators that will virtually take participants to the Oil, Gas & Salt Resources Library and the Arkona Area to learn about paleoenvironment.

Click the images for information on Dates, Fees, Deadlines, Delivery mode, and Caps:

See Fieldtrips Fees, Deadlines, and Registration Information  Summary Pre- and Post- meeting Fieldtrips and delivery mode.  

Enrollment and payment for one or more fieldtrips will be available at the time of Registration. Fieldtrip leaders will send information pertinent to the access and timing, as well as other details for virtual and in-person fieldtrips once you register. Further field trip details are given below and updates may be found on the GAC-MAC 2021 website: https://gacmac2021.ca/

The unusual hydrology and sedimentary record of Crawford Lake

Leader: Francine McCarthy (Brock University)

[Virtual, asynchronous]

Cost: $40

Varves accumulate in the deep karstic basin of Crawford Lake on the Niagara Escarpment, allowing changes in water chemistry and the lake ecosystem to be dated with annual resolution. These disturbances were primarily anthropogenic, and archeological evidence of Iroquoian and subsequent Euro-Canadian activities can still be seen in its small watershed. Calcite precipitates in the alkaline waters of the mixolimnion of this permanently stratified lake, forming a summer light-coloured layer and the dark part of the couplet is organic matter, primarily from mass mortality of plankton after fall turnover. Unlike most meromictic lakes, the bottom waters are highly oxygenated, and a diverse micro-invertebrate fauna in found below the chemocline, including ostracods, cladocerans, copepods and rotifers. Groundwater flowing into this sinkhole via aquifers in the Lockport Group contains enough dissolved oxygen to allow aerobic metabolism year-round in the monimolimnion. Because light inorganic-dark organic couplets accumulate in a non-reducing environment, the varved sequence of Crawford Lake, is being assessed as a potential GSSP for the Anthropocene Epoch

Crawford Lake view from interpretive boardwalk on dolomitic bedrock. Photo credit: Francine McCarthy.
A drive through the city of waterfalls: exploring the Niagara Escarpment in Hamilton, Ontario

Leaders: Rebecca Lee (McMaster University), Carolyn Eyles (McMaster University), Alexander Peace (McMaster University)

[ Virtual, asynchronous]

Cost: $35

The Niagara Escarpment is a steep-sloped cuesta that stretches from New York State through Ontario and into Michigan and Wisconsin. It is composed of Ordovician to Devonian sedimentary deposits, primarily dolostones, shales and sandstones. Across the length of the escarpment, there is significant variation in its lithological characteristics, including unit thicknesses and jointing patterns. This field trip will explore outcrops of the Niagara Escarpment in the city of Hamilton, an area that shows significant change in the nature of exposed lithological units. The escarpment runs through Hamilton, separating the lower and upper city which are connected by 19 access roads. Hamilton is also known as the city of waterfalls, a moniker related to the over 100 waterfalls that cascade over the escarpment edge. The escarpment here is of interest to the local community, to researchers, and to city planners as its continuous erosion and change causes issues with the safety of the roads and building near its edge. The trip will include stops at the Devil’s Punchbowl in east Hamilton, the Jolley Cut in Central Hamilton, and the Chedoke Radial Trail in west Hamilton. At each of these locations the sediments, fossils, and other features of interest will be discussed in detail. Throughout the trip, the lateral changes in lithological characteristics occurring across the escarpment within the city will be discussed and highlighted. Other sites may be included, time permitting, to further elucidate the lithological characteristics of the Niagara Escarpment. 

One of many escarpment region waterfalls drops over Paleozoic strata at the Devil’s Punchbowl, Hamilton, ON. Photo credit: Rebecca Lee.
A Virtual Field Trip to the Eastern Midcontinent Rift – Canada

Leader: David Good (Western University)

[ Virtual, synchronous, pre-meeting]

Cost: $40

The mafic igneous rocks of the northeast shoulder of the Midcontinent Rift are petrologically and geochemically distinct from those of the more widely studied northwest shoulder. We will examine numerous sites from the spectacular Lake Superior shoreline to as far east as Timmins, including Mamainse Point, Chesapeake falls, Pukaskwa National Park, the great Abitibi dyke, and the Coldwell Complex. We will visit a wide range of Midcontinent Rift related volcanic and intrusive rocks that cut the Archean terrane northeast of Lake Superior. Because we are virtual, we can visit many of the best outcrop exposures located off the beaten path from the spectacular Lake Superior shoreline to as far east as Timmins. The rocks have alkaline or tholeiitic affinities. Planned stops include: 1) Chippewa Falls and Mamainse Point to see pahoehoe lava flows, interflow conglomerates, and the basal contact with Archean granite, 2) Rift perpendicular tholeiitic dykes such as the Kipling dyke and the 700 km long Great Abitibi dyke, 3) Rift parallel alkaline dykes of the Copper Island and Pukaskwa dyke suites, 4) the Coldwell Complex (the largest alkaline intrusion in North America) to see (i) partial melting at the Archean footwall contact, (ii) classic intrusive relationships between nepheline syenite and alkaline gabbro at Neys Provincial Park, (iii)interlayered alkaline and tholeiitic basalt from the margin to center of the complex,and (iv) some of the highly unusual but distinguishing igneous features at two of thebest-known copper palladium deposits located in the eastern MCR (the Geordie Lakeand Marathon deposits).

Pukaskwa dyke (~1106 Ma) intruded along plane of weakness in deformed Archean pillow basalt (in left cliff face). Photo credit: David Good.
Geology of the Huronian Supergroup north of Lake Huron, Canada – a fieldtrip in memory of Grant M. Young

Leaders: Patricia Corcoran (Western University), Gordon Osinski (Western University), Carolyn Hill-Svehla (Western University)

[ In-person, post-meeting]

Cost (In-person): $1000 (Max. Participants: 20)

  • Note: Virtual asynchronous version of this Fieldtrip has been cancelled – Only in-person version will be available

The rocks of the Paleoproterozoic Huronian Supergroup will be examined at various locations in Ontario. We will view most Huronian sedimentary formations, including: 1) the Matinenda Formation, which hosts the uranium-rich deposits in Elliot Lake, 2) the mudstone-siltstone deposits of the McKim and Gowganda formations in Espanola, 3) the dropstones, varves and other glaciogenic deposits of the Gowganda and Ramsey Lake formations near Iron Bridge, Elliot Lake and Whitefish Falls, 4) the carbonate-rich Espanola Formation in Espanola, 5) the quartz-rich sandstone deposits of the Lorrain, Bar River, and Serpent formations at various localities, and 6) evidence for early life in the Gordon Lake Formation near Flack Lake. Participants will also visit the Sudbury basin, which is host to the Sudbury Igneous Complex, Whitewater Group and Huronian sedimentary rocks containing impact-related structures. 

Paleoproterozoic Lorrain quartzite of the Huronian Supergroup, exposure overlooking Whitefish Falls, Ontario. Photo credit: Patricia Corcoran.
Earth Sciences Field Trip for Educators – London and Arkona

Leaders: Lesley Hymers (Mining Matters), Deana Schwarz (Association of Professional Geoscientists of Ontario Education Foundation)

[Virtual, asynchronous]

Cost: $20

The Arkona area of southwestern Ontario is well-known for its abundance of fossils and continues to attract the interest of fossil collectors from near and far. This virtual field trip will highlight the geological history of southwestern Ontario and the paleoenvironmental conditions that were present during the Devonian Period. The trip features virtual site visits to several locations, beginning with the Oil, Gas & Salt Resource Library in London, Ontario. Next, participants will visit the famous Hungry Hollow quarry where they will learn about the fossilized organisms that are present there and how they once lived through a series of photographs and videos narrated by Dr. Cameron Tsujita and local fossil expert Bob O’Donnell. Other locations include the Rock Glen Conservation Area, a Thedford outcrop, and Kettle Point. The trip concludes with a tour of the newly-renovated Arkona Lion’s Museum and Information Centre, led by Museum Steward Bob O’Donnell. 

Hungry Hollow outcrop location near Arkona, Ontario. Photo credit: Deana Schwarz.

COVID-19 Statement

Due to the COVID-19 pandemic, the London 2021 Local Organizing Committee is closely following updates from regional and national authorities, and planning accordingly for this fast-evolving situation. The health, safety, and well-being of all participants is our priority consideration in our decisions, and we will provide updates on this site as needed.

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English (Canada)