Howard Street Robinson Medal
The Howard Street Robinson Medal recognizes a respected and well-spoken geoscientist who will further the scientific study of Precambrian Geology and/or Metal Mining through a presentation of a distinguished lecture across Canada. The medal is named in honour of Howard Street Robinson, a founding member of the GAC whose bequest to GAC in 1977 of approximately $100,000 makes the lecture tour possible. The bequest was ”for the furtherance of scientific study of Precambrian Geology and Metal Mining”. Thus the GAC’s Mineral Deposits Division awards the medal in odd years, and the Precambrian Division awards it in even years. The lecturer is nominated and chosen by the Howard Street Robinson Medal Committee.
2019 Howard Street Robinson Medalist
JoAnne Nelson (British Columbia Geological Survey)
JoAnne Nelson is an Emeritus Scientist with the British Columbia Geological Survey (BCGS), after a 31 year career as a regional mapping geologist specializing in the tectonics, structural geology and metallogeny of the northern Cordillera. She is the senior author on two articles synthesising Cordilleran tectonics and metallogeny (SEG Special Volume 17, 2013; GAC-MDD Special Publication 5, 2006); co-edited GAC Special Volume 45 with Maurice Colpron on Cordilleran pericratonic terranes; and co-authored The Geology of British Columbia with Sydney and Richard Cannings (Greystone Books, 2011).
JoAnne’s accomplishments were formally recognized in 2013 when she was listed in the top 100 Global Inspirational Women in Mining by the United Kingdom’s Standard Bank. In 2015, she was presented with the Gold Pick Award by the Kamloops Exploration Group (KEG) in recognition of “outstanding services and contributions to the minerals industry”. AME awarded her a Special Tribute for scientific leadership in 2016, and in 2017 she received the Canadian Provincial and Territorial Geologists’ Medal.
Upcoming lecture tour dates (some details are still TBD):
Monday, Nov 4, 11:30 am – UBC Okanagan, Kelowna – Science Building, Room 374
Tuesday, Nov 5 – University of Calgary and Mount Royal University, Calgary
Wednesday, Nov 6, 9:30 am – University of Regina – Classroom Building, Room CL125
Wednesday, Nov 6, 11:45 am – Saskatchewan Geological Society – Bushwakker’s Brew Pub, 2206 Dewdney Avenue, Regina – This is an SGS sponsored luncheon for SGS members, however non-members are welcome to join for the talk (starts at 12:15 pm) without the purchase of a luncheon plate, or make arrangements to purchase a luncheon plate ($20 per plate) by contacting Alexander Pollard (Alexander.firstname.lastname@example.org) in advance.
Thursday, Nov 7, 3:00 pm – University of Saskatchewan, Saskatoon – W.P. Thompson Building, Biology Room 106
Thursday, Nov 7, 11:30 am – Canadian Institute of Mining, Saskatoon Geosection – Travelodge Hotel Saskatoon, 106 Circle Drive
Friday, Nov 8, 12:00 pm – University of Alberta, Edmonton – Henry Marshall Tory Building, Room 3-36
Past lecture tour dates:
Monday Sept 16, 3:00 pm – Carleton University, Ottawa – 2110 Herzberg Building
Tuesday Sept 17, 12:00 pm – UQAM, Montreal – 201 Av. President-Kennedy, Room PK-7605
Wednesday Sept 18, 12:00 pm – McGill, Montreal – Frank Dawson Adams Building, Room 232
Thursday Sept 19, 11:30 am – ULaval, Quebec City – 1065 Av. Medecine, PLT building, Room 4118 (Two talks back-to-back)
Friday Sept 20, 12:30 pm – UNB, Fredericton – Forestry/Geology Building, Room F104
Monday Sept 23, 11:30 am – Saint Mary’s University, Halifax – Science Building, Room 441
Tuesday Sept 24, 12:00 pm – Acadia University, Wolfville – Huggins Science Hall Room 336
Wednesday Sept 25, 1:15 pm – St. Francis Xavier University, Antigonish – Physical Sciences Center, Room 2045
Wednesday Oct 2, 1:00 pm – Memorial University, St. John’s – Alexander Murray building, Room ER-4065
The great Triassic-Jurassic Cu-Au-Mo porphyries of the central Canadian Cordillera: Why there? Why then?
The Canadian Cordillera has developed as an orogenic belt over 700 million years, beginning with a Neoproterozoic-Early Cambrian intracontinental rift that created the western margin of Laurentia. Its history as an active tectonic region continues today, though interactions with the Pacific Plate: earthquakes along the Queen Charlotte and Denali transform faults, and collision of the Yakutat block that is lofting the St. Elias Mountains and creating a zone of tectonic instability that extends over 1000 kilometres inland to the eastern front of the MacKenzie Mountains. Construction of the Cordilleran orogen was preceded by evolution and interaction of offshore and exotic terranes, which eventually accreted to the western Laurentian (North American) cratonal margin, primarily in Middle Jurassic to Cretaceous time. During a relatively short time interval prior to accretion (220-178 Ma), world-class belts of porphyry and related gold deposits – famous names like Highland Valley, Mt. Milligan, Afton, Copper Mountain, Red Chris and KSM-Brucejack – emerged in two of the offshore terranes, Quesnellia and Stikinia. This presentation attempts to explain how, in the larger context of Cordilleran evolution, Quesnellia and Stikinia became perfect porphyry hosts, and why Cu-Au-Mo porphyries flourished in the two separate terranes during the same brief period of time. To grasp the long-term processes that primed and prepared the lithosphere of these two multistage island arc terranes, and the profound tectono-magmatic events that triggered porphyry emplacement in them, is to understand that their full metallogenetic potential has yet to be realized. Major deposit discoveries in the last decade (Red Chris, KSM-Brucejack, Tatogga, Deep Afton) illustrate this optimistic view: that like the history of the Cordillera itself, the saga of exploration within it is set to continue into unknown future time.
British Columbia’s “Golden Triangle”: Arc-axial porphyry belt, or mineralized deep-crustal corridor?
The “Golden Triangle” refers to the Iskut district, an exceptionally well-mineralized region within the Stikine multiphase arc terrane of northwestern British Columbia. The district extends 250 kilometers from Kitsault in the south to the village of Iskut in the north and the Stikine River in the northwest. Major porphyry camps within it include Schaft Creek and Galore Creek (Late Triassic) in the northwest, the Red Chris-GJ-North Rok-Tatogga cluster near Iskut (latest Triassic), and the KSM-Brucejack and Snip Bronson (Early Jurassic; porphyry-gold vein) camps in the centre of the belt. The host intrusions have been considered arc-axial bodies, associated with the Late Triassic Stuhini and Early Jurassic Hazelton arcs. Although coeval volcanic sequences are present, new paleogeographic interpretations suggest that the main Stuhini and Hazelton arc fronts lay elsewhere within Stikinia.
This presentation focuses instead on the first-order features of the Iskut district: its prolonged, complex and varied metallogenetic history, and the key role of structures in localizing both individual deposits and the mineralized district as a whole. The overall structural grain of northwestern Stikinia shows sets of northerly fault arrays that are interrupted at intervals by narrow, orthogonal easterly fault systems. Schaft Creek and Galore Creek show strong northerly control by penecontemporaneous faults. The ~12 km long northerly KSM porphyry trend lies in the immediate footwall of a north-striking Cretaceous thrust fault, interpreted as a reactivated Early Jurassic synmineral lineament. Red Chris is localized along a minor splay of the easterly Pitman fault system, as is the newly discovered Saddle Zone at the Tatogga property which, like KSM, lies in the immediate footwall of a later thrust fault. The sets of northerly and easterly lineaments exerted control on some of the oldest intrusive bodies in Stikinia, the Late Devonian Forrest Kerr and More Creek plutons, as well as the youngest post-accretionary overlap unit, the QuaternaryRecent Mt. Edziza volcanic complex. They probably originated as fundamental zones of weakness in the unexposed, unknown pre-Devonian basement of north-central Stikinia.
Besides porphyry and porphyry-related gold deposits, the Iskut district also hosts volcanogenic massive sulphides, notably Granduc (Late Triassic), and Eskay Creek and Anyox (Middle Jurassic). Eskay Creek and Anyox lie within a narrow, post-arc rift zone, the Eskay rift, that follows the entire length of the northerly axis of the Iskut district, with older porphyry deposits on both sides. Granduc lies along the western bounding fault of the rift, the South Unuk-Harrymel fault, which is probably an expression of a co-spatial Late Triassic back-arc structure. A second, subsidiary rift hosts the Dolly Varden Ag-rich VMS deposit (Middle Jurassic), which lies along strike with the Homestake Au-rich porphyry occurrence.
The great mineral endowment of the Iskut district is due to its location along intersecting sets of longlived deep crustal lineaments that provided conduits for magmas and fluids during a succession of tectonic regimes. Although the bulk of “Golden Triangle” mineralization is of Late Triassic – Early Jurassic age, the Kitsault molybdenum porphyry deposit at its southern tip was emplaced in Eocene time. The multi-phase tectonic and metallogenetic history of the Iskut district is reminiscent of large-scale crustal breaks such as the Larder Lake – Cadillac fault zone in the Superior province. Such lineaments provide ideally fertile ground and permeability conditions that can, and do, result in near-superposition of vastly different mineral deposit types.