Overview of Results from the Greenstone ... - Geology Ontario

Introduction
The western part of the southern Abitibi greenstone belt (SAGB) contains some of the world’s largest
copper-zinc and gold deposits and significant amounts of nickel-copper-platinum group element (PGE)
mineralization. Early discoveries were made by classical prospecting with subsequent discoveries
commonly resulting from diamond drilling targeted by electromagnetic surveys. The next generation of
deposits will be found at greater depth, principally beneath the extensive overburden that covers most of
the Abitibi greenstone belt. Thus, exploration will require improved knowledge of the geological
characteristics of the existing deposits, the stratigraphic, plutonic, structural and metamorphic architecture
of the region and will rely more heavily on expensive geophysical and geochemical techniques, verified
by diamond drilling.
The Abitibi greenstone belt is typical of many mineralized environments in that there is excellent
knowledge of the immediate surroundings of the mineral deposits and knowledge of the regional scale
setting. The understanding of the geology at the subregional and district scales is less clear, because of
regional-scale stratigraphic variations and, in some cases, complex metamorphic and structural overprints.
The objective of this project is to improve knowledge of the stratigraphy, volcanology, geochemistry,
metamorphic petrology, and structural geology of the greenstone belt, emphasizing selected mineralized
and barren areas in order to better understand the geological architecture of the belt. The project has
increased our knowledge of the stratigraphy, lithological variation, structural patterns, geochemical
variation, and alteration, and metamorphic overprints involved in the localization and genesis of Cu-Zn,
Ni-Cu-PGE and Au deposits, and will aid in the development of new concepts for discovering deposits.
The purpose of this project was to provide new field-based geological and geochemical data and new
concepts that can be used to more effectively and efficiently explore for gold and base metal deposits in
the Timmins–Kirkland Lake region of the Abitibi greenstone belt (Figure 1). The project will contribute
directly to new base metal and gold discoveries by 1) providing a better understanding of the
stratigraphic, plutonic, structural and metamorphic architecture of the region, 2) identifying fundamental
controls on localization and genesis of gold and base metal mineralization utilizing a variety of “state of
the art” approaches, and 3) developing new geological tools for more effective exploration, thereby
reducing exploration risk, especially in poorly exposed areas.
Although detailed mapping has been a key component of the project applied to the critical parts of
the greenstone belt, the results of this detailed research have been extended to provide complete and equal
coverage of, and generate an enhanced level of knowledge of, the entire Timmins–Kirkland Lake area.
This overview report summarizes the various individual subproject results reported through the stream of
maps, reports and workshops, culminating in this synthesis.
APPROACH
The approach taken was to mount thematic subprojects with emphasis on the following:
1. Improving knowledge of the stratigraphic framework for the greenstone belt as a whole. This has
involved development of stratigraphic sections in the Kidd–Munro, Blake River, Tisdale, Porcupine
and Timiskaming assemblages followed by expansion outward to the scale of the entire belt using
geochemistry, geochronology, tracing of key marker horizons and structural relationships as tools in
the stratigraphic and structural interpretation.
2. Understanding the fabric relations and their relative timing in the development of lode gold deposits
and applying this understanding to regional-scale structures, plutonic event chronologies and
metamorphism.
1