Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    83     STATION    5086
EASTING   568042     NORTHING   6044110     ZONE   14     DATUM   NAD83
Date of mapping    07/04/1983

STRUCTURAL DATA

Planar Structures:
Structure type Strike Dip Separation
gneissosity 81 65

PETROLOGIC DATA

Rock Number: 1

Rock Type: granodiorite
Descriptors:
porphyritic
biotite-plagioclase bearing

Field Description:

- Outcrop is 70% younger granodiorite, intruded by numerous intrafolial quartz poor potassic pegmatites.
-moderate injection of highly sheared aplitic matierial.
-in general the extent of lit injection is much greater than typical for the granodiorite

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
groundmass grainsize 0.0 3.0 mm
mafic mineral biotite 0.0 0.0 12.0 %

Rock Number: 2

Rock Type: tonalite
Descriptors:
schlieric or schlieren present
leucocratic

Field Description:

-extremly deformed highly compressive tonalite, biotite schlieren common
-boudinage and augen structures of pegmatitic lit dominate the foliation plane
-folding both ptygmatic and z-assymetric

Rock Number: 3

Rock Type: amphibolite
Descriptors:
layered
biotite - hornblende bearing

Field Description:

-origin uncertain, extensivley intruded by pegmatite
- vague suggestions of layering, may have a sedimentary component.
-probably part of the greenstone environment but far too deformed and recrystallized to be certain.
-forms low flat rubbly outcrops parallel to shoreline

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
mafic mineral 0.0 0.0 40.0 %


Manitoba Geological Survey, 2017