|Title||Regional mapping protocol, descriptive nomenclature and field database coding for iron oxide alkali-alteration (IOAA) ore systems and their IOCG, IOA and affiliated deposit types
|Author||Corriveau, L; deToni, A; Montreuil, J F; Wahl, J; Guilmette, C; Guilmette, S; Champagne, M; Dourlet, S|
|Source|| 2015 p. 1-3|
|Alt Series||Earth Sciences Sector, Contribution Series 20150013|
|Publisher||Geological Association of Canada|
|Meeting||2015 Joint Assembly AGU-GAC-MAC; Montreal; CA; May 3-7, 2015|
|Media||paper; on-line; digital|
|Subjects||metallic minerals; economic geology; metamorphism, thermal; thermal alteration; iron oxides; iron ores; skarns; gold; copper; uranium; volcanogenic deposits; uranium deposits; skarn deposits; breccia
deposits; contact metasomatic deposits; apatite; IOAA; IOCG; IOA|
|Program||South Rae Province Bedrock/Surficial geology, GEM2: Geo-mapping for Energy and Minerals|
|Abstract||Iron oxide alkali-alteration (IOAA) ore systems create the largest metasomatic (hydrothermal alteration) systems known within the continental crust. The metasomatic processes culminate into:|
vanadium and specialised-metal ores within iron oxide±apatite (IOA or Kiruna-type) deposits,
2) base-, precious-, specialised- and nuclear-metal ores or by-products within magnetite-, magnetite to hematite- and hematite-group IOCG deposits,
3) polymetallic ores within certain skarns and albitite-hosted uranium deposits.
Each of these deposit types is a consequence of the systemic development of metasomatic facies across the upper crust as its geotherms rise abnormally during
regional-scale ascent of highly saline high-temperature fluid columns. From depth-to surface, fluids strongly react with and transform intensely and pervasively precursor rocks over about 30x5x10 km to form a series of alteration facies with their
own, newly acquired, bulk- rock and mineral composition, mineral assemblages, grain sizes, textures and even structures. In addition, veins, stockworks and breccias abound and fills are most commonly associated with extensive alteration haloes.
Alteration can replace, cross cut, be transitional to, juxtaposed upon, superimposed upon precursor rocks or earlier alteration types. In the process, some units may ¿disappear¿ from their stratigraphic sequence, being totally altered. Identifying
and mapping these alterations are fundamental to modern geomapping for energy and minerals and for future exploration and deposit discovery as each alteration type vectors to its own deposit type and metal association.
illustrates the megascopic geological attributes of these metasomatic systems. Then it highlights the mapping protocols, nomenclature and field database codification system for mapping across the IOAA systems of the Labrador Trough (Québec) as part
of the Geomapping for Energy and Minerals (GEM2) program in collaboration with its partner the Ministère des Ressources naturelles du Québec.
|Summary||(Plain Language Summary, not published)|
This GEM2 - Hudson-Ungava project contribution illustrates the megascopic geological attributes of iron oxyde alkali alteration ore systems. Then it
highlights the regional to local mapping protocols, the nomenclature and the field database codification system developed for the regional mapping across the Labrador Trough (Québec). This protocl is required as currently our field mapping tool is
unable to capture the geology of such systems during our Geomapping for Energy and Minerals (GEM2) program. The codification system is being developed in collaboration with our GEM2 partner: the Ministère des Ressources naturelles du Québec.
Identifying and mapping these alterations are fundamental to modern geomapping for energy and minerals and for future exploration and deposit discovery as each alteration type vectors to its own deposit type and metal association.