This is an announcement for a paired special session and field trip ...

This is an announcement for a paired special session and field trip
concerned with metamorphosed ore deposits, to be held at the GAC-
MAC Joint Annual Meeting in Winnipeg, May 22-28, 2013.
The metamorphic events (full details below) consist of:
Special session: Metamorphism in the ore environment
One of W-Th-F May 22-23-24, 2013
Invited speakers:
Dr. Andy Tomkins (Monash University): The critical role of
deformation in metamorphic sulfide melting.
Dr. Paul Spry (Iowa State University): The use of trace element
chemistry of gahnite and garnet as exploration guides to Broken Hilltype
mineralization.
Field trip: Metamorphosed alteration zones and regional
metamorphism, Trans-Hudson Orogen, Manitoba
F-Sa-Su-M-T May 24-28, 2013
Abstracts are currently being accepted up until the deadline of
January 21, 2013 at the meeting website:
http://www.gacmacwinnipeg2013.ca
Registration for all events (special session, field trip) opens on
March 1, 2013.
Details of metamorphic events:
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1. SS-12 Metamorphism in the ore environment
Session description: This session is concerned with all aspects of
metamorphism and ore deposits, including: metamorphism of ore
bodies; regional and contact metamorphism in mining districts;
metamorphism of mineralization-related alteration zones;
metamorphic minerals as ‘vectors’ to metamorphosed ore deposits;
metamorphically-related remobilization; sulphide anatexis during
metamorphism; and the role of metamorphic fluids in generating or

modifying ore bodies.
Invited guest speakers:
Dr. Andy Tomkins (Monash University): The critical role of
deformation in metamorphic sulfide melting.
Dr. Paul Spry (Iowa State University): The use of trace element
chemistry of gahnite and garnet as exploration guides to Broken Hilltype
mineralization.
Convenors: Chris Couëslan (Manitoba Geological Survey;
chris.coueslan@gov.mb.ca), Doug Tinkham (Laurentian University;
dtinkham@laurentian.ca), David Pattison (University of Calgary;
pattison@ucalgary.ca), Simon Gagné (Manitoba Geological Survey;
simon.gagne@gov.mb.ca)
Session details
Date: One day out of Wednesday-Thursday-Friday, May 22-23-24,
2013 (exact dates TBA)
Supported by: GAC Mineral Deposits Division and the Society of
Economic Geologists
Location: Winnipeg convention centre in downtown Winnipeg.
Presentation options: oral presentations (20 minutes) and posters
(balance to be dictated by Meeting organizers)
Cost: included in meeting registration (meeting costs TBA)
Abstract deadline: January 21, 2013.
Abstract submission: through the GAC-MAC Winnipeg 2013
website (http://www.gacmacwinnipeg2013.ca).
Special Session and Meeting registration: through the GAC-MAC
Winnipeg 2013 website (http://www.gacmacwinnipeg2013.ca).
Registration opens March 1, 2013.
Social activities associated with Special Session: We plan to
have an informal (pay as you go) group dinner on the evening
following the Special Session at a nearby restaurant. Details TBA.
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2. Post-meeting field trip:
Metamorphosed alteration zones and regional metamorphism:

Examples from the Trans-Hudson Orogen
Dates: Friday–Tuesday, May 24-28, 2013
Leaders: Chris Couëslan (Manitoba Geological Survey;
chris.coueslan@gov.mb.ca), Doug Tinkham (Laurentian University;
dtinkham@laurentian.ca), Al Bailes (Bailes Geoscience;
bailesgeoscience@mts.net), Simon Gagné (Manitoba Geological
Survey; simon.gagne@gov.mb.ca)
Field trip description:
Regional metamorphism in the Paleoproterozoic Trans-Hudson
Orogen has resulted in greenschist to granulite facies assemblages.
This field trip will focus on the effects of regional metamorphism in a
variety of ore environments and will summarize previous work and
present the results of recent work on defining and mapping isograds
and delineation of metamorphosed hydrothermal alteration zones.
Localities to be visited will include:
Thompson Nickel Belt:
Paleoproterozoic Ospwagan Group rocks, which are host to the Nibearing
ultramafic intrusions of the belt, were subjected to low
pressure metamorphism during the Trans-Hudson metamorphism. A
series of nested metamorphic domains elongate parallel to the
regional strike of the belt progress from staurolite+andalusite to
sillimanite to sillimanite+K-feldspar to K-feldspar+garnet+cordierite
assemblages. Recognizing the Ospwagan Group rocks at various
metamorphic grades is an added challenge to Ni-exploration in the
belt.
Snow Lake area:
Metamorphosed VMS alteration systems were recognized in bimodal
volcanic and volcaniclastic rocks of the Snow Lake arc assemblage
(1.89 Ga). The primitive “Anderson” sequence is host to the
Anderson, Stall and Linda deposits whereas the “mature” Chisel
sequence is host to the Chisel, Ghost and the newly discovered Lalor
deposits. The mineralization is spatially associated with rhyolite
complexes and synvolcanic intrusive rocks. The mineralized volcanic
sequences contain prominent zones of alteration formed by

synvolcanic hydrothermal activity which were subsequently
recrystallized during 1.81 Ga regional mid-amphibolite facies
metamorphism. The alteration zones are easily recognized with their
distinctive metamorphic mineral assemblages. Centimetre-scale,
euhedral crystals of chlorite, phlogopitic biotite, amphibole,
muscovite, garnet and staurolite are common within metamorphically
recrystallized semi-conformable alteration zones. Recrystallized
discordant alteration zones also contain coarse-grained kyanite and
andalusite. Three major periods of hydrothermal activity are identified
within the Snow Lake arc assemblage.
Sherridon area:
Paleoproterozoic Sherridon gneisses are dominantly derived from
felsic volcanic rocks that host several VMS deposits within the
Sherridon structure. Paleoproterozoic deformation, upper amphibolite
facies metamorphism and partial melting of felsic gneiss complicates
the identification of VMS hydrothermal alteration systems associated
with the Cu-Zn deposits. Controversial garnet-sillimanite-biotite
assemblages containing cordierite and/or gedrite are derived from
hydrothermally altered felsic volcanics, some of which themselves
experienced partial melting, but locally could represent partially
melted sediments. Garnet-cordierite-gedrite assemblages developed
in altered mafic rocks are widespread throughout the structure but are
volumetrically insignificant compared to the altered felsic rocks.
Cost and registration:
Cost: $730 CDN, on top of the meeting registration fee
What’s included: transportation, accommodation in hotels (double
room occupancy), packed lunches, dinners, breakfasts, juice/water
during the field days, and a field guide.
Enrollment limit: 16.
Registration: through the GAC-MAC Winnipeg 2013 website.
Registration opens March 1, 2013.
Logistical details:
Departure time and place: 12 noon on Friday, May 24 th at the
Winnipeg Convention Center.
Return time and place: 7 pm on Tuesday, May 28 th at the Winnipeg

Airport and/or Winnipeg Convention Center.
Towns where we will be staying the night: Thompson, Snow Lake,
Bakers Narrows, Flin Flon.
Mode of transport: Rental vehicles. Rather than drive back to
Winnipeg, participants can choose to fly from Flin Flon to Winnipeg at
the end of the trip (May 28 th ) at their cost.
Style of field trip: a mixture of roadside outcrops and traverses.
Weather in May in central/northern MB: unpredictable, 0°C and
snow to 25°C and sun.
Hammers and sampling: sampling is allowed at many of the stops.
Out-of-pocket expenses: all alcoholic beverages, supper on the
evenings of May 24 th and 27 th , breakfast and lunch on May 28th.
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We look forward to seeing you in Winnipeg!
Best wishes,
Chris Couëslan, Doug Tinkham, Dave Pattison, Simon Gagné, Al
Bailes