Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 83 STATION 5161
EASTING 573060 NORTHING 6049790 ZONE 14 DATUM NAD83
Date of mapping 07/24/1983

STRUCTURAL DATA

PETROLOGIC DATA

Rock Number: 1

Rock Type: pegmatitc granite
Field Description:

-pegmatite granite
-extreme crystal size variation
-extensive areas of very coarse Z folded granite with muscovite +/- biotite in wide thin books randomly orientated
-opposite range is ultra coarse graphic microcline crystals up to 2.5 x 3.0 m
-scattered irregular quartz cores with large thick muscovitr books, large tourmaline and garnet and sub-euhedral blocky microcline
-traces of bluish green apatite
-contact zone same as before--zone of narrow pegmatitic lit in rock changing over 2 to 3 m into massive grey psammite with only old deformed lit and quartz veins

PHOTOS

Unique pegmatitc granite. Characterized by extreme crystal size variation. Photo shows very coarse 2 feldspar 2 mica granite surrounding giant graphic microcline crystals that can reach 2-3 metres in size.

Additional view of mega-graphic microcline. Note the large books of biotite that are randomly oriented in the very coarse granite phase.

Close-up view of the pegmatitic granite showing large euhedral non-graphic microcline in a quartz, albite, biotite muscovite matrix.

Manitoba Geological Survey, 2017