Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    83     STATION    5001
EASTING   571846     NORTHING   6046645     ZONE   14     DATUM   NAD83
Date of mapping    06/17/1983

STRUCTURAL DATA

Layering:
Layering type Strike Dip top Direction
bedding 286 71 N

Planar Structures:
Structure type Strike Dip Separation
schistosity 286 71

Dikes and Sills:
Rock Number Type Width (m) Strike Dip
0 pegmatite 0.20 208 76

-slightly sheared quartz poor pegmatite
-photos bedding in gr. greywacke
-deformed, some boudinage 20 cm

PETROLOGIC DATA

Rock Number: 1

Rock Type: greywacke
Descriptors:
bedded
psammite
faser kiesel (sillimanite-quartz knots) present
parallel laminated
graded bedding present

Field Description:

-Dominantly graded and parallel laminae layers with minor ripple layers.
-No E division numerous faserkiesel in semi pelite layers.
-Minor 10-30cm amphibolite layers
Turbidite

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
faser kiesel sillimanite 1.0 10.0 4.0 cm
groundmass grainsize 0.0 0.5 mm
bedding thickness 1.0 10.0 cm

Minerals of Note
Mineral Abundance (%)
garnet
sillimanite

Rock Number: 2

Rock Type: wacke
Descriptors:
laminated
mafic

Field Description:

-As at 1st stop an amphibolitic wacke/tuff mixture.
-Mainly to south of greywacke

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
mafic mineral hornblende 0.0 0.0 30.0
groundmass grainsize 0.0 0.2 mm

Minerals of Note
Mineral Abundance (%)
hornblende
garnet

Rock Number: 3

Rock Type: aplite
Descriptors:
massive
granitic
dike

Field Description:

-Bright pink with a glassy look
-numerous dikes parallel to contact with granodiorite; range from 5 cm to 1 m in thickness
-scattered potassium feldspar megacrysts

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
phenocryst potassium feldspar 0.0 0.0 mm

PHOTOS


Graded bedding in garnet-sillimanite bearing greywacke. Thin layer of hornblende-garnet+/-dioside amphibolite exhibits boudinage. Greywacke has disruption of layering and incipient mobilizate developing in the semi-pelitic beds.


As previous photo showing prefferential shearing an isoclinal folding in the bedding plane of the most pelitic beds.


Oblique view of previous photo


Manitoba Geological Survey, 2017