Trip 1 (pre meeting)
Title: Geology of the Lac des Iles Palladium mine
Dates: Monday August 5, 2024
Trip Leaders: Lionnel Djon and Lac des Iles geology team
The field trip at the Lac des Iles Palladium Mine promises an engaging exploration of key geological features. The journey will commence with a scenic viewpoint overlooking the Roby and Sheriff pits. Participants will delve into discussions regarding the spatial relationship between the high-grade hanging-wall schist and the lower grade footwall breccia rocks which taken together form the >10 M Oz Roby-Offset-Camp Lake deposit. Noteworthy satellite ore zones, including Sheriff, Powerline, Roby NW, and Roby SW, will also be reviewed.
Continuing north of the Roby Pit, the tour will visit the North VT Rim outcrop exposure. Participants will assess vari-textured norite and bonanza-grade Pd mineralization, gaining valuable insights into the metal distribution and zonation at Lac des Iles. The journey will progress northeast to Creek Zone, offering a firsthand look at the stratigraphy of the Mine Block Intrusion in recently exposed trenches. This area features vari-textured and brecciated units to the north, mineralized norite to the south, and magnetite gabbro near the intrusion core. Additionally, ultramafic rocks from the adjacent North Lac des Iles complex, such as websterite and clinopyroxenite, can be observed at Creek Zone.
Concluding the field trip, participants will explore the discovery outcrop at Baker Zone, located approximately 1 km northeast of the Roby Pit. Here, a diverse array of magmatic breccia textures will be on display, alongside Ni-Cu-PGE mineralization linked to fine-grained disseminated chalcopyrite and coarse-grained chalcopyrite-pentlandite-pyrrhotite blebby intergrowths. The interpreted vertical breccia pipe structure comprises leucocratic vari- textured norite and hetero-lithic breccia units, forcefully intruding the mela-norite host rocks of the East Mine Block area. The observations at Baker Zone hold significant implications for understanding the relative timing of magmatic breccia formation.
Upon returning from the field, Impala Canada geologists will guide a comprehensive review of selected drill core in the core logging facility, providing participants with further insights into the geological complexities encountered during exploration.
Trip 2 (pre meeting)
Title: Cu-PGE deposits of the Coldwell Complex (Caldera), Ontario
Dates: Sunday, August 4 th to Monday August 5 th , 2024
Trip Leader: Dave Good
This two-day field trip will feature three unique Cu-PGE deposits within the caldera structure of the Proterozoic Coldwell Complex on the northeast shoulder of the Midcontinent Rift. Mineralization types include:
- pyrrhotite- to bornite-rich assemblages and extreme PGE enrichment at the Marathon deposit,
- bornite-chalcopyrite assemblage associated with skeletal olivine in troctolite breccia at the Geordie Lake deposit, and
- chalcopyrite-pyrrhotite assemblage within apatite-olivine-clinopyroxene cumulate rocks at the Four Dams occurrence.
We will spend a full day examining outcrops at the Marathon deposit plus drill core for the Geordie and Four Dams deposits. The remaining time will be spent on field stops that feature:
- pre-caldera metabasalt,
- syn-caldera layered intrusions at the Marathon deposit,
- various members of the Geordie-Wolfcamp Series including an alkaline dyke that cuts the Archean, and
- intrusive breccias of post-caldera alkaline gabbro within late, quartz saturated to unsaturated syenite sills on the Coldwell Peninsula.
Trip 3 (post meeting)
Title: Mesoproterozoic Ni-Cu Deposits of Northeastern Minnesota
Dates: Friday, August 9 – Monday, August 12, 2024
Trip Leaders: Jim Miller, University of Minnesota Duluth (retired); Mark Severson, Natural Resources Research Institute, UMD (retired); Brian Goldner, Talon Nickel; Sam Weatherley, New Range Cu-Ni; Kevin Boerst, Twin Metals
This four-day field trip will highlight the geologic setting and mineralization styles of two major occurrences of Ni-Cu-PGE sulfide deposits associated with the 1.1 Ga Midcontinent Rift exposed in northeastern Minnesota. A full day will be devoted to examining drill core from several deposits exposed along the basal intrusive contact of the massive, gabbroic Duluth Complex. These will include New Range Cu-Ni's Northmet and Mesaba deposits and Twin Metal’s Maturi deposit. The following day will focus on viewing mineralized drill core from Talon Nickel's Tamarack deposit, which is hosted by an ultramafic chonolithic intrusion emplaced into Paleoproterozoic metasediments. Additional field stops will visit classic outcrops of Midcontinent Rift geology exposed along the North Shore of Lake Superior and a half-day excursion through type locality of the Duluth Complex at Duluth.