Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    84     STATION    5503
EASTING   576428     NORTHING   6042152     ZONE   14     DATUM   NAD83
Date of mapping    06/29/1984

STRUCTURAL DATA

Planar Structures:
Structure type Strike Dip Separation
schistosity 40 41

Dikes and Sills:
Rock Number Type Width (m) Strike Dip
0 Molson dike 0.25 149 78

PETROLOGIC DATA

Rock Number: 1

Rock Type: tonalite
Descriptors:
schistose
leucocratic

Field Description:

-bulk of outcrop is a white weather grey on fresh surf., slightly schlieric TNLT
-it is probably part of Clearwater Bay complex
-if this is so it is one of the best preserved examples
-it holds a very unusual intrusive relation with rock #2
-margins of large rafts are commonly pegmatitic containing brecciated inclusions of mafic and ultramafic rocks
-rock #1 Sample B - duplicate sample for analysis

Rock Number: 2

Rock Type: granodiorite
Descriptors:
gneissic
hornblende - garnet bearing

Field Description:

-unusual rock type not encountered before
-it is a moderatly mafic subgneissic homog. equigranular grey brown GRDR containing scattered, highly deformed mafic schlieren and oval garnet quartz agg. reg. up to several cm in diametre
-it's extensivly intruded by garnetiferous quartz monzanite pegmatite
-the whole w side of island is GRDR
-the origin of mafic inclusions along the boundary is uncertain but would seem to support the idea that GRDR is a rafted complex


Manitoba Geological Survey, 2017