Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 85 STATION 6061
EASTING 570107 NORTHING 6047831 ZONE 14 DATUM NAD83
Date of mapping 06/19/1985

STRUCTURAL DATA

Planar Structures:
Structure type | Strike | Dip | Separation
cataclastic foliation | 269 | 78 |

PETROLOGIC DATA

Rock Number: 1

Rock Type: gneiss
Descriptors:
mesocratic
tonalitic
Field Description:

-grayish brown weathering with dark grey surface, strong schistocity
-contains inclusions of massive ampb
-unit ut by rock type 2, then cut by rock type 3 at which time an anatomozing vein network of feldspathic, HB-epidote seams formed and then was cut by rock type 4

Minerals of Note
Mineral | Abundance (%)
hornblende

Rock Number: 2

Rock Type: tonalite
Descriptors:
leucocratic
Field Description:

-dikes up to 1 m or more with an associated vein swarm in rock type 1.
-this rock is sheared and shows the same HB-epidote alteration as the earlier unit

Rock Number: 3

Rock Type: amphibolite
Descriptors:
massive
gabbroic
Field Description:

-foliated, veined, old gabbroic intrusive that contains inclusions of TNLT gneiss
-this is cut by fine feldspathic stringers and quartz veins but does not show same HB-epidote alteration as earlier units
-gabbro may have caused the alteration in the TNLT's

Rock Number: 4

Rock Type: diabase
Descriptors:
foliated
Field Description:

-60 cm dike of old mafic intrusion
-strong fabric and deformed margins
-this unit crosses TNLT gneiss and truncates veins of Rock type 2 and HB-epidote alteration seams
-fine grained and was probably pyroxene bearing
-not a Molson
PHOTOS
1 diabase cutting TNLT Gneiss
2 TNLT gneiss with leuc TNLT veins and alteration veins cut by diabase
3 Gabbro ampb with inclusions of old TNLT
4 General shot of Gabbro ampb
5 ampb inclusions in TNLT gneiss
6 alteration veins cutting and offsetting leuco TNLT
7 leuco TNLT cutting TNLT gneiss

Manitoba Geological Survey, 2017