Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 83 STATION 5050
EASTING 571498 NORTHING 6040094 ZONE 14 DATUM NAD83
Date of mapping 06/23/1983

STRUCTURAL DATA

Planar Structures:
Structure type | Strike | Dip | Separation
gneissosity | 41 | 60 |
fault | 306 | 75 |

Dikes and Sills:
Rock Number | Type | Width (m) | Strike | Dip
0 | Molson dike | 0.15 | 10 | 65

diabase Molson dyke on small island due east of the station

PETROLOGIC DATA

Rock Number: 1

Rock Type: multi-component schlieric gneiss
Field Description:

9 samples taken and numbered as per the list below
10 rock types evident here:
1) "Old" tonalite - this is the older tonalitic phase of the main core of the Clear Water Bay complex - NOT the old unit with the preserved old fabric that occurs as inclusions
2) grey porphyritic granodiorite-tonalite
3) various ages of pegmatite
4) volcanic amphibolite
5) grey fine grained quartz-plagioclase-biotite gneiss
6) mesocratic megacrystic granodiorite with a pronounced cross-fabric of old 270 crossed by the 050 fabric- possibly related to rock 1
7) medium grained hornblende metagabbro
8) coarse megacrystic mesocratic hornblende augen quartz diorite
9) porphyritic hornblende diorite
10) massive hornblendite
Indications that this may be a core area for the grey granodiorite - it is the dominant rock type and gives conflicting impressions of age sequences.
The apparent age sequence is interpreted as follows:
1,2,3 young intrusive rocks that form the major bulk of the current complex
4,5 supracrustal rocks included in the younger units
6,7,8,9,10 old "basement" gneisses (no relative age implied in the numbers 6-10)
Entire complex cut by the 050 mylonite fabric

Manitoba Geological Survey, 2017