Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 83 STATION 5052
EASTING 571834 NORTHING 6040050 ZONE 14 DATUM NAD83
Date of mapping 06/23/1983

STRUCTURAL DATA

Planar Structures:
Structure type | Strike | Dip | Separation
cataclastic foliation | 41 | 61 |
gneissosity | 41 | 61 |

minor mylonite seams in the foliation plane

PETROLOGIC DATA

Rock Number: 1

Rock Type: tonalite
Descriptors:
light grey
grey
old phase
Field Description:

- equal amounts of tonalite and various late grey granodiorite phases.
-These include a fine to medium grained grey granodiorite that shows good intrusive realtionship into the tonalite gneiss; the normal porphyritic granodiorite and a coarsely porphyritic granodiorite.
-minor mylonite seams are common in the foliation plane

Rock Number: 2

Rock Type: granodiorite
Descriptors:
dark grey
black
fine to medium grained
Field Description:

-young intrusive with sharp imtrusive contacts into old tonalite and including or dyking into the other granodiorite units

Textural Features
Type | Mineral | Min. Size | Max. Size | Abundance (%) | Unit
mafic mineral | biotite | 0.0 | 0.0 |  | mm

Rock Number: 3

Rock Type: porphyritic granodiorite
Descriptors:
grey
dark grey
porphyritic
massive
Field Description:

older of the 2 dominant late granodiorite to tonalite intrusives

Textural Features
Type | Mineral | Min. Size | Max. Size | Abundance (%) | Unit
phenocryst | plagioclase | 2.0 | 5.0 | 10.0 | mm
mafic mineral | biotite | 0.0 | 0.0 |  |

Rock Number: 4

Rock Type: granodiorite
Descriptors:
light grey
dark grey
megacrystic
Field Description:

not a common phase - appears to be approximately the same age as rock 3, may be related.

Textural Features
Type | Mineral | Min. Size | Max. Size | Abundance (%) | Unit
phenocryst | plagioclase | 0.0 | 20.0 |  | mm
mafic mineral | biotite | 0.0 | 0.0 |  |

Manitoba Geological Survey, 2017