HazyFieldNotes The Temegami Greenstone Belt. (TGB) in Northeast Ontario, CA

Photos
1. Devil Mountain, on Devil Lake. underlain by Nipissing diabase, which forms a 2.2 billion year old magmatic province with an east–west extent of almost 450 km (280 mi) and a north–south extent of up to 350 km (220 mi).
2. Spirit Rock on Chee-Soy lake. Surrounded by Obabika’s Old Growth forest. The place is a first nations spiritual site for Teme-Aguama, nipissings, and other first nations, and I can see why. You just feel the world is so much bigger than you when taking it in. This is also the largest continuous stand of red and white pines remaining in the world, and it has trees over 380+ years old.
3. Close-up of banded iron formation. Whitish = quartz-rich, Dark gray = magnetite-rich, Reddish = hematite/jasper-rich The outcrop shown here consists of BIFs - banded iron formations. BIFs are unusual, dense sedimentary rocks consisting of alternating layers of iron-rich oxides and iron-rich silicates. Most BIFs are Proterozoic in age (although some are Late Archean), and do not form today - they're "extinct"! Many specific varieties of iron formation are known, and some are given special rock names. For example, jaspilite is an attractive reddish & silvery gray banded rock consisting of hematite, red chert ("jasper"), and specular hematite or magnetite. This outcrop has magnetite-quartz-jasper BIF.
4. Pillow Lava, indicating lava erupted underwater.
5. Bonus: We saw the northern lights. I don’t know much about astronomy, but my buddy on the trip does and was saying we are in a rare pocket of time were you can see the lights like this in the summer, and after the next few years we’ll have to wait 11 years to see them like this again!
History of the Area
The Temagami Greenstone Belt (TGB) is a small 2.7 billion year old greenstone belt in the Temagami region of Northeastern Ontario, Canada. It represents a feature of the Superior craton, an ancient and stable part of the Earth's lithosphere that forms the core of the North American continent and Canadian Shield. The belt is composed of metamorphosed volcanic rocks that range in composition from basalt to rhyolite. These form the east-northeast trend of the belt and are overlain by metamorphosed sedimentary rocks. They were created during several volcanic episodes involving a variety of eruptive styles ranging from passive lava eruptions to viscous explosive eruptions. Felsic volcanic vents are present througout the region.
Part of the Canadian Shield, the TGB contains some of the oldest known rocks on Earth. The belt is made up of a number of geologic features such as batholiths, stocks, dikes, volcanic complexes, layered intrusions and deformation zones. These are situated in several geographical townships in the municipality of Temagami, including Chambers, Strathy, Strathcona, Briggs and possibly Best.
Geology
Geologists assume that greenstone belts were formed by many geological processes, such as tectonism, magmatism, metamorphism and sedimentation. They are important economically for large metal deposits, and for the insight they provide into crustal evolution and the tectonics of the early Earth Uranium-lead dating has established that the Iceland Lake Pluton, as well as an adjacent rhyolitic lava flow, is about 2,736 million years old. Therefore, at least some intrusions were likely formed during the first volcanic phases in the belt and may have been conduits for volcanic eruptions.
The name "Temagami" is Ojibwe in origin, meaning "deep clear water"; until 1968 it was spelt as "Timagami". This spelling of the name appeared on all official maps and related documents when it was adopted on June 25, 1906. In early 1968 the Canada Post Office applied to the Geographical Names Board of Canada for a spelling reform to Temagami at the instigation of the general public. The Executive Secretary of this committee subsequently applied to the Lands and Surveys Branch of the Ontario Department of Lands and Forests. This former department, now part of Ministry of Natural Resources, corresponded with the proposed renaming of Timagami on March 20, 1968, as well as for Lake Timagami, Timagami Island and the Timagami River.
Mineral explorations
In May 1995 Pacific Mariner Exploration carried out a small drilling program on its properties in Strathy Township to estimate the likelihood of base metal deposits. A hole was drilled under Net Lake in Temagami North, but its collapse prevented the survey's completion. As a result, little is known about its geophysical features. Most of the property was influenced by Net Lake and included ten adjacent mining claims. The larger region is known for it’s iron mining, but gold, copper, and nickle were also mined from the area.

#geology#Canada #stuffIfoundinthefield

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HazyFieldNotes kuchlkastl7 asked:Awesome information! Would you mind sharing how you recommend viewing the region? It looks peaceful! Thank you! To be honest, I was just a willing follower of the canoe trip my friend lead. Here is his reddit post documenting the trip. I think he has a map on there! It was as about as peaceful as you could expect with 3 guys who thought they could live off of unrefrigerated hot dogs and s’mores for 5 days. #ask#geology#Canada#landscape #volcano #plants #nature #coast
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