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Geology of the Wecho River Area

Outcrop photograph of biotite-grade greywacke-mudstone turbidites. Island in Mosher Lake. Photo taken by B. Fyson.
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Outcrop photograph of cordierite in greywacke. Cordierite aligned with and wrapped by foliation, but the generation (i.e. S2/S3) is uncertain. South end of Mosher Lake.
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Outcrop photograph of sillimanite porphyroblasts in semipelitic rock. Pen magnet north. Outcrop ~10 kilometres south of Inglis Lake.
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Outcrop photograph of diatexite with large cordierite (iolite) porphyroblasts. Northeast of Germaine Lake.
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Outcrop photograph of bedding and Smain in mid- to upper-amphibolite grade psammitic rocks. Smain is defined by melt in these psammitic beds, whereas sillimanite defines Smain in pelitic beds. Southwest of Armi Lake. Pen magnet north (towards left of photograph).
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Photomicrograph of a mid- to upper-amphibolite grade semipelitic rock. Smain (defined by sillimanite) is cross-cut by a crenulation cleavage (Slate - defined by biotite). Smain is at least S2 on a regional scale. Plane polarized light. Sil = sillimanite; Bt = biotite.
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Outcrop photograph of semipelitic metatexite. Melt zones and garnet-rich (red) layers are indicated. The brown to brown-red layers are restite (semipelitic protolith). South of Dauphinee Lake. Pen magnet north (towards left of photograph). Grt = garnet.
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Photomicrograph of intergrown cordierite, garnet, and biotite in a metatexite from the northern part of the study area. K-Feldspar is not shown. Inset is an outcrop photograph of cordierite (blue) overprinting garnet (red) and intergrown with K-Feldspar (pink-beige). Crd = cordierite; Grt = garnet; Bt = biotite.
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Outcrop photograph of silicate/oxide (garnet-amphibole/magnetite) iron formation. Red coloured garnet- and magnetite-rich layers and silica-rich, possibly recrystallized chert layers, are indicated. This iron formation attained granulite grade as evidenced by intergrown garnet, cordierite, and K-Feldspar (not shown) on the same outcrop exposure. South of Dauphinee Lake. Pen magnet north (towards lower left of photograph). Grt = garnet; Mgt = magnetite.
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Outcrop photograph of flattened pillowed flow in mafic volcanic unit. North of Mosher Lake.
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Photomicrograph of spatially associated orthopyroxene, clinopyroxene, hornblende and quartz in an enderbite sample from the northern part of the study area. Plane polarized light. Inset is same photomicrograph but taken under cross polarized light. Opx = orthopyroxene; Cpx = clinopyroxene; Hbl = hornblende; Qtz = quartz.
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Outcrop photographs of gossans in turbidites, mafic volcanic rocks, and iron formation. Gossans in similar relationships throughout the Slave craton have known gold showings. Northwest corner of map area (NTS 85O/03).
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