Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    83     STATION    5069
EASTING   571124     NORTHING   6038591     ZONE   14     DATUM   NAD83
Date of mapping    06/25/1983

STRUCTURAL DATA

Planar Structures:
Structure type Strike Dip Separation
cataclastic foliation 56 72

-complex mafic to intermediate dike sequence

PETROLOGIC DATA

Rock Number: 1

Rock Type: multi-component schlieric gneiss
Descriptors:
complex
tonalitic
granodioritic

Field Description:

-complex tonalitic to granodioritic gneiss sequence much as on north side and in Clearwater Bay

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
mafic mineral biotite 0.0 0.0 4.0 %

Rock Number: 2

Rock Type: quartz diorite
Descriptors:
beige in color
grey
massive
leucocratic
salt and pepper texture
intrudes rock #1

Field Description:

-extensive areas of coarse salt and pepper beige to white weathering intermediate rock that intruded the MCSG
-quartz 10 to 15 %

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
mafic mineral hornblende 0.0 0.0 12.0 mm

Minerals of Note
Mineral Abundance (%)
quartz 12.0

Rock Number: 3

Rock Type: diorite
Descriptors:
charcoal grey
black
massive
intrudes rock #1
intrudes rock #2
boudin or boudinaged

Field Description:

Many large boudins 1-3 m across by several metres long of mafic, occassionally porphyritic diorite
-Shows obvious intrusive contacts on both rocks 1 and 2

Approximate sequence of events:
1) intrusion of main tonalite
2) extensive tonalitic veining
3) deformation
4) intrusion of quartz diorite (rock #2)
5) intrusion of diorite (rock #3)
6) extensive shearing
7) deformation and folding
8) late shearing and cataclasis

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
mafic mineral hornblende 0.0 0.0 35.0 %
phenocryst plagioclase 0.0 0.0


Manitoba Geological Survey, 2017