Cross Lake Project (1983-86)
Geologist P.G. Lenton
Year 83
STATION 5075
EASTING 571567
NORTHING 6038885
ZONE 14
DATUM NAD83
Date of mapping 06/27/1983
STRUCTURAL DATA
Structure type | Strike | Dip | Separation |
---|---|---|---|
fault | 237 | 74 |
Rock Number | Type | Width (m) | Strike | Dip |
---|---|---|---|---|
0 | pegmatite | 0.03 | 105 | 80 |
30-55 cm ultramylonite
-photos
1 Tonalite-granodiorite contact
2 Amphibolite raft with dike of mafic tonalite
3 agmatite of amphibolite in tonalite
4 schlieric termination of inclusions in tonalite
5 deformation associated with cataclasis in granodiorite
6,7,8 minor structures associated with mylonite
PETROLOGIC DATA
Rock Number: 1
-Dominant rock type is grey-white weathering quartz rich leucocratic tonalite.
-appears to be the youngest rock in the outcrop
-it is intrusive into all others except late pegmatites
-quartz 30-35 %
Type | Mineral | Min. Size | Max. Size | Abundance (%) | Unit |
---|---|---|---|---|---|
mafic mineral | biotite | 0.0 | 0.0 | 4.0 | % |
groundmass grainsize | 0.0 | 1.0 | mm |
Mineral | Abundance (%) |
---|---|
quartz | 33.0 |
Rock Number: 2
-coarser grained less quartz rich (quartz 20 %) grey weathering intrusive granodiorite. Slightly plagioclase megacrystic.
-occurs as inclusions in leucotonalite.
-is crossed by deformed pegmatite and late undeformed pegmatite
Type | Mineral | Min. Size | Max. Size | Abundance (%) | Unit |
---|---|---|---|---|---|
mafic mineral | biotite | 0.0 | 0.0 | 10.0 | mm |
groundmass grainsize | 1.0 | 3.0 | |||
phenocryst | plagioclase | 0.0 | 0.0 |
Mineral | Abundance (%) |
---|---|
quartz | 20.0 |
Rock Number: 3
-massive poorly foliate mafic tonalite (looks quartz diorite but has 20 to 25 % quartz) with salt and pepper texture and even grained homogeneous appearance.
-Intrusive into the volcanics and contains amphibolite inclusions
-Occurs as large rafts in Rock 1 and 2 but dominantly in 1.
-cut by old and young pegmatites.
Type | Mineral | Min. Size | Max. Size | Abundance (%) | Unit |
---|---|---|---|---|---|
mafic mineral | hornblende | 0.0 | 0.0 | 25.0 | % |
groundmass grainsize | 1.0 | 2.0 | mm |
Mineral | Abundance (%) |
---|---|
quartz | 22.0 |
Rock Number: 4
-large inclusions highly deformed mafic amphibolite.
-probable massive and possibly pillowed flows with minor sediments of volcanic origin
PHOTOS
Contact between leucotonalite and the old augen granodiorite.
Amphibolite raft cut by dike of mafic hornblende tonalite.
Agmatite of amphibolite in the mafic hornblende tonalite
Schlieric termination of a mafic inclusion in tonalite
Deformation associated with cataclasis in older granodiorite.
Minor structures associated with mylonite zone in augen grandiorite
Minor structures associated with mylonite zone in augen grandiorite
Mylonite produced classic straight gneiss in augen granodiorite.
Manitoba Geological Survey, 2017