Temagami greenstone belt

The Temagami greenstone belt is an Archean greenstone belt in Temagami, Ontario, located Unit km|100|0 northeast of Sudbury, Canada. It is characterized by felsic-mafic volcanic rocks and averages about Unit km|13|0 wide and Unit km|29|0 long with the dominant structure being a northeast trending syncline called the Tetapaga Syncline that has been modified by the emplacement of granitic rocks. The metavolcanic and metasedimentary units are composed of a different suite of volcanic rocks and clastic chemically precipitated sedimentary rocks. The Temagami greenstone belt has been intruded by three separate granitoid intrusions, the Strathy-Chambers and Spawning Lake Batholiths and the Iceland Lake Pluton.

The major topographic feature in the Temagami greenstone belt is the northeastern arm of Lake Temagami, which is underlain by a strong fault zone of sheared felsic to intermediate metavolcanics that is approximately Unit m|1200|0 wide.

Economic geology

The Temagami greenstone belt is the host for large banded iron formation as well as numerous precious metal and base metal deposits and occurrences, such as aragonite, brochantite, calcite, chalcopyrite, jasper, magnetite, molybdenite, pentlandite, pyrite, pyrrhotite, serpentine, and talc. As a result, several mines opened. Some of these mines were Sherman Mine, Kanichee Mine and Copperfield's Mine on Temagami Island, which once mined the richest copper ore in Canada. [ [http://www.temagamivacation.com/trails.asp Experience a Temagami Vacation] ] While the Temagami region is fairly quiet, the treat of mining in the Temagami greenstone belt is looming ever closer with the discovery of potentially diamond-bearing kimberlite bodies. [ [http://www.tres-or.com/tm.php Diamond Discoveries] ]

The metasedimentary and metavolcanic rocks along the the southern limb of the Tetapaga Syncline consist of massive to pillowed iron-rich tholeiitic basalts some 2 billion years old in the lowest unit, and intermediate to felsic effusive and pyroclastic rocks with banded iron formation within the central unit 2.7 billion years old. [ [http://student.britannica.com/comptons/art-107856/A-banded-iron-formation-rock-recovered-from-the-Temagami-greenstone Britannica Student Encyclopedia] ] The pillowed tholeiitic basalts indicate that great submarine volcanoes existed during the early stages of the Earth's crust.

Kanichee layered intrusive complex

The Kanichee layered intrusive complex is the largest of several mafic-ultramafic bodies in felsic and mafic metavolcanic rocks in the northern portion of the Temagami greenstone belt. It is layered and consists of five Ni-Cu-sulfide-bearing cycles of mainly dunite to clinopyroxenite cumulate rocks, formed from repeated pulses of high-magnesium basalt. The first of these cycles contained a small tonnage of Ni-Cu-PGE ore, now mined out by the Kanichee Mine. However, an accurate estimate of the composition of each pulse is unknown. [ [http://rruff.geo.arizona.edu/doclib/cm/vol22/CM22_93.pdf Geology and Petrogenesis of the Kanichee layered complex, Ontario] Retrieved on 2007-11-24]

ee also

*Volcanism in Canada
*Canadian Shield
*Temagami Magnetic Anomaly

References