ILSG - Thunder Bay 2012

We are planning a whole bunch of great trips for the 2012 meeting. Although nothing is guaranteed yet, here is a list of what we have so far to whet your apetite

Pre-Meeting trips

Sudbury Impactoclastic Debrisites at Thunder Bay - SOLD OUT

Trip leaders: Bill Addison and Greg Brumpton

The 1.85 Ga Sudbury impact unleashed a sequence of extraordinary events, the evidence for which will be seen at five sites near Thunder Bay. Emphasis will be on relating the features seen to the dynamics of the chaotic processes associated with this massive energy release.The field trip will be limited to the first 25 people to sign up. A second post-meeting trip will be scheduled if numbers warrant.

Geology of the Sibley Peninsula

Leaders: Dr. Philip Fralick (Lakehead University) Mark Smyk & Riku Metsaranta (Ontario Geological Survey)

This trip will examine a variety of Proterozoic rocks that underlie the Sibley Peninsula, just east of Thunder Bay. Paleoproterozoic sedimentary rocks of the Animikie Group (Gunflint and Rove formations) are disconformably overlain by Mesoproterozoic Sibley Group (Pass Lake and Rossport formations) sedimentary rocks. These rocks are intruded by a number of mafic dykes and sills related to the Midcontinent Rift. Other topics for discussion will include Penokean deformation and the famous Silver Islet Mine, located just off the end of the peninsula in Lake Superior.

Lac des Iles Pd mine - SOLD OUT

Leader: John Corkery (North American Palladium Ltd.)

This trip to the producing Lac des Iles Pd Mine, located 90km north of Thunder Bay, will include: a property-wide review discussing the current activities, exploration, and geology of a unique mafic-ultramafic complex; a review of type sections of drill core from the Offset zone and in-progress drill core from active pit benches; a visit the North VT-Rim zone trenches, where the contact between the vari-textured (VT) gabbro and the overlying rhythmically layered gabbro is exposed (Pd grades from channel samples between 10 and 60 grams per tonne); and a hike to examine the very well-exposed Baker zone stripped area, which is the original PGE discovery site for the Lac des Iles deposit.

The Shebandowan greenstone belt

Leaders: A. Aubut (Sibley Basin Group Geological Consulting Services Ltd.) and D. Campbell (Ontario Geological Survey)

The Shebandowan field trip will focus on the geology and mineralisation associated with Neo-Archean rocks deposited in pull-apart basins. The older Archean rocks in this area are characterised by numerous komatiitic ultramafic bodies, one of which is host to the past producing Shebandowan Ni-Cu-PGE mine that was deformed by the Crayfish Creek Fault, a reactivated pull-apart basin boundary fault. We will also examine a suite of basin fill sediments and volcanics, usually described as being “Timiskaming-type”, that unconformably overly the older Archean, “Keewatin-type” rocks. Locally these are host to magnetite iron formation and auriferous ladder veins within late felsic intrusive bodies. Limit: ~24 people.

Syn-meeting trips

Geology of the City of Thunder Bay

Mark Smyk (Ontario Geological Survey)

This afternoon trip will provide a brief overview of the Archean, Proterozoic and Quaternary geology of the Thunder Bay area by focusing on two key field trip stops. Hillcrest Park is a spectacular vantage point for this geologic overview and provides outstanding exposures of Sudbury ejecta/debrisite. The trip will also include a visit to Kakabeka Falls, the "Niagara of the North", to look at the Paleoproterozoic Gunflint Formation sedimentary rocks which unconformably overlie Archean granitoids

Panorama Amethyst Mine

Leader: S. Kissin (Lakehead University)

The trip will visit the largest amethyst producing deposit in the Thunder Bay area Details of the geology and mineralogy will be highlighted based on research on the deposit. There will be an opportunity to purchase specimen material. Limit ~45 people.

Port Arthur building stone walking tour

Leader: P. Hinz (Ontario Geological Survey)

This leisurely walking tour of downtown Port Arthur will examine the architecture and building stones utilized in the development of early Thunder Bay. Proterozoic rocks quarried in the Nipigon area will be highlighted in historic buildings constructed during the late 1880s to early 1930s, these will be contrasted with modern day construction utilizing Archean stone quarried west of Thunder Bay.

Post-meeting trips

Highway 527 Transect (2 days) - SOLD OUT

Leader: Mark Smyk (Ontario Geological Survey) & Phil Fralick (Lakehead University)

The first day of this transect along Highway 527 between Thunder Bay and Armstrong will highlight representative Neoarchean supracrustal, granitoid and metamorphic rocks of the Wawa, Quetico and Wabigoon subprovinces (a.k.a. Wawa-Abitibi, Marmion and Winnipeg River terranes; Quetico Basin) of the Superior Province. The second day will feature Mesoproterozoic rocks of the Southern Province. These locally include ca. 1110 Ma Midcontinent Rift-related diabase sills; the Pillar Lake volcanic suite; Sibley Group sedimentary rocks (ca. 1340 Ma) and the Badwater gabbro-syenite intrusion (1599-1590 Ma). This trip involves an overnight stay in Armstrong (double-occupancy). Limit: 20 persons

Rehabilitation of the Past-Producing Shebandowan and North Coldstream Mines

Leader: Mark Puumala, Ministry of Northern Development and Mines

This trip will provide on overview of rehabilitation measures that have been implemented at the Shebandowan and North Coldstream Mine sites. Operations at both mines produced sulphide-rich tailings and waste rock. An overview of the rehabilitation measures that have been implemented at each site to prevent and/or mitigate acid rock drainage will be provided. Field trip participants will require personal protective equipment, including safety boots, hard hat, safety glasses and reflective vest.

Geoarchaeology of Thunder Bay

Leader: S. Hamilton (Lakehead University)

The Thunder Bay area contains a number of Paleo-Indian archaeological sites, many of which are associated with relic shorelines of Glacial Lake Minong or exposures of the Gunflint Formation, the primary source of tool stone. This tour visits some of these sites to reflect upon the landscape associations, and how that contributed to the settlement system of the first humans to occupy the region after deglaciation.

Midcontinent rift intrusions

Leaders: R. Cundari (Lakehead University), P. Hollings (Lakehead University) and M. Smyk (Ontario Geological Survey)

This trip will examine a number of mafic intrusive units associated with the 1.1 Ga Mesoproterozoic Midcontinent Rift System preserved in the Thunder Bay area. Stops will include examples of Nipigon diabase sills, Logan diabase sills, Pigeon River dykes and the newly recognized Riverdale sill. The trip will also include several picturesque stops such as Mount McKay and the Palisades. Topics for discussion will be timing relationships between MCR-related intrusions, geochemistry and paleomagnetism of intrusive units, as well as overall Midcontinent rift dynamics.

Musselwhite gold mine - SOLD OUT

Leader: J. Biczok (Musselwhite Mine)

The Musselwhite gold mine, located on the south shore of Opapimiskan Lake, is hosted in the North Caribou Greenstone belt. The mine began production in 1997 and is currently classified as a giant deposit with past production plus current reserves and resources totaling of 5.41 million ounces (as of December 31, 2010). The deposit comprises multiple orebodies within two banded iron formations that are part of the Opapimiskan-Markop unit of the McGruer assemblage. The majority of gold mineralization is hosted within the Northern Iron Formation where it is largely confined to subvertical shear zones in tightly folded areas, particularly where steeply dipping, isoclinal fold limbs transition into the crests or keels of antiformal and synformal structures (e.g., PQ Deeps, T-Antiform, Esker, Jets). Gold occurs primarily within the pyrrhotite-filled fractures in garnet grains and less so as scattered grains in the green amphibole, feldspar, pyroxene and quartz veins. This field trip will leave from Thunder Bay Airport and participants will fly to the mine site where they will visit both surface and underground exposures.

Sudbury Impactoclastic Debrisites at Thunder Bay.

Trip leaders: Bill Addison and Greg Brumpton

Due to popular demand we have added an additional post-meeting trip

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