Geology 200a - Lab 6 Rocks typical of the Early Proterozoic and Archean of Canada
4-9; Early Proterozoic; quartz pebble conglomerate - rounded pebbles and cobbles supported in (cemented by) a matrix of pyrite and quartz; chemically and mature clastic material; basal Huronian; exhumation of high level sialic crust; mined for uranium; Elliot Lake.

4-10a; Early Proterozoic; polymictic conglomerate (diamictite) -: mainly rounded granitoid cobbles in a gritty siltstone to mudstone matrix; likely a continental glacial deposit; Huronian Gowganda Formation; Elliot Lake region.

4-10b; Early Proterozoic; planar laminated mudstone; varve-like bedding suggests deposition during a glacial period; Huronian Gowganda Formation; Elliot Lake region.

4-11a; Early Proterozoic; intensely green fuchsite-bearing quartzite (Temagami ‘Jade’); green colour of the fuchsite (sericite; muscovite) is due to the presence of Cr derived from detrital chromite, which is itself derived from komatiitic rocks of the Archean Abitibi belt; .

4-11b; Early Proterozoic; tan to light grey, dense, faintly compositionally layered, isoclinally folded quartzite; faint pale green tinge of the rock is due to the presence of detrital chromite (see comment in 4-11a); the rock is therefore derived from the weathering of both ultramafic and granitoid rocks of the Abitibi belt; Lorrain Quartzite of the Huronian, Whitefish Falls, Sudbury region

4-12a; Early Proterozoic; compositionally layered quartz-kyanite-andalusite meta-arenite; kyanite suggests an aluminous, clay-rich sedimentary protolith, which itself implies intense weathering of an Archean granitoid terrane during the early Proterozoic; (Huronian Lorrain Formation on the north limb of the La Cloche syncline, Whitefish Falls).

4-12b; Early Proterozoic; soft, well foliated, brown to red brown, garnet-staurolite-schist; staurolite is a brown mineral, commonly found in the form of a cross, and a poor basal cleavage; metamorphism of an aluminous sedimentary protolith; McKim Formation, Sudbury region.

4-12c; Early Proterozoic; staurolite-bearing, bedded argillites; staurolite growth restricted to the darker argillitic beds of the specimen; McKim Formation; Big Nickel, Sudbury.

4-12d; Early Proterozoic; dark green, pervasively foliated mica schist, really a phyllite because the minerals are microscopic (they are muscovite or biotite, but there may also be some chlorite which gives the rock the overall green color); porphyroblasts are chloritoid, or chloritoid retrogressed to mica - chloritoid is a hard, dense, green mineral, sometimes mistaken for chlorite; it has the same composition, but lower metamorphic grade than staurolite; metamorphism of an aluminous sedimentary protolith; McKim Formation, Espanola road cut, Sudbury region.

4-12ep1; 4-12ep2; Early Proterozoic; biotite-garnet-staurolite schist; high P/T metamorphic terrane, likely an Al-rich, sedimentary protolith.

4-13; Early Proterozoic; grey laminated lime mudstone (bulbous stromatolites) draped by ?oolitic wackestone-packstone with faint lamination- well sorted; restricted, saline, supratidal environment (lagoon) flooded by sea-level rise which formed high energy near shore beach-like environment; stromatolites abundant in the Proterozoic perhaps due to the lack of predators; Wyoming.

4-14a; Early Proterozoic; magnetic, well bedded, very heavy, tabular and lensoidal ribbons of hematite and magnetite- banded iron formation; primary type of iron deposits referred to as "Superior-Type Banded Iron Formations"; Animikie; northern Michigan.

4-14bp1; 4-14bp2; Early Proterozoic; native silver (oxidized black, maleable) in coarse-grained, grey sparry calcite; hydrothermally altered and mineralized Nipissing diabase of the Cobalt region, northern Ontario (Cobalt is the silver capital of Canada.)

Sudbury 8-1; Impact; non-penetrative fracture surfaces in fine grained sandstone; fracture surfaces are curved and covered with horsetail lineations; shatter cones; Sudbury region.

Sudbury 8-3a - 8-3h; Impact; brecciated rock composed of fragment of Archean gneiss in a very fine grained pseudotachylitic matrix; Windy Lake, north rim of the Sudbury Basin.

Sudbury 8-6; Impact; coarse granophyre with acicular amphibole intrusive into the quartz gabbro outcrops on the south side of the road where highway 144 branches to Windy lake, north rim of the Sudbury basin.

Sudbury 8-25a; Impact; carbon-rich fall back breccia, clearly exhibiting clasts with extremely irregular sutured outlines; the rims of the clasts are formed of coarsely recrystallized glass; High Falls pylon line sequence.

Sudbury 8-25b; Impact; impact melt rock; note flow banding; High Falls pylon line sequence.

************************************************************************************* 4-15a; Archean; compositionally layered, anorthosite/garnet-amphibolite gneiss;; likely an ol-plag cumulate ultramafic protolith; deformed anorthosite complex in lower crustal crystalline Archean basement exhumed in the Kapuskasing uplift.

4-15b; Archean; migmatitic amphibolitic gneiss (annealed tectonite), crystalline Archean basement- permeation of tonalitic and granitic fluids into what may originally have been a relatively massive amphibolite derived from mafic volcanics or gabbro; Kapukasing uplift.

4-16a; Archean; spinifex textured upper part of a komatiite flow; spinifex composed of olivine; extrusion of ultramafic lavas early in Earths history when heat flow was much higher than today; Abitib belt; Munro Township, Matheson.

4-16b; Archean; spinifex textured komatiite mafic flow; spinifex composed of pyroxene; Abitibi belt; Boston Township, Kirkland Lake.

4-17a; Archean; komatiitic basalt; flow top breccia; serpentinized, tan weathered - note injections of lava between the fragments of the breccia, commonly referred to as "beef string" structure; Abitibi belt, Kirkland Lake.

4-17bp1; 4-17bp2; Archean; massive, felsic autoclastic volcanic flow breccia; contains abundant fine grains of pyrite; likely hydrothermally altered; Abitibi belt, ?.

4-18; Archean; brown weathered, cordierite porphyryblastic amphibolite or metabasalt- commonly referred to as ‘dalmatianite’ - groundmass is aphanitic; removal of alkali elements during hydrothermal alteration causes growth of Mg-rich cordierite, often associated with large base metal deposits; from Amulet A Mine, Abitibi belt of the Superior Province; Rouyn-Noranda, Quebec

4-19a; Archean; black to steel grey, dense, magnetic, finely crystalline, iron formation; chemical sediment with all iron as magnetite; no hematite; Abitibi belt, Timagami.

4-20; Archean; coarse-grained, equigranular, pale grey to tan weathered hornblende - biotite tonalite; emplacement of granitoid plutons represents final stage in the construction of a continent; Abitibi belt.

4-21; Archean; silver grey to white weathered, soft, pervasively foliated tourmaline-bearing sericite schist; tourmaline looks like black, acicular amphibole, but it is triangular in cross-section; protolith likely a potassic felsic volcanic (ash tuff); this rock is associated with gold mineralization at Canada's world class Hemlo Gold deposit.

4-22; Archean; late stage mollasse conglomerate of the Timiskaming Formation,; Cadillac - Larder Lake (break) fault zone; zone of Au mineralization; note distinct green clasts of komatiitic material; Rouyn-Noranda, Abitibi belt, Superior Province.