Cross Lake Project (1983-86)

Geologist    P.G. Lenton     Year    83     STATION    5042
EASTING   571202     NORTHING   6041591     ZONE   14     DATUM   NAD83
Date of mapping    06/23/1983

STRUCTURAL DATA

Planar Structures:
Structure type Strike Dip Separation
gneissosity 11 76

Dikes and Sills:
Rock Number Type Width (m) Strike Dip
2 diabase 2.20 283 78

-inclusion of layered amphibolite

PETROLOGIC DATA

Rock Number: 1

Rock Type: tonalite
Descriptors:
porphyritic
leucocratic
gneissic

Field Description:

-same as before except megacrysts are slightly more obvious
-strange 0.2 x 3.0 m lenticular pods of pegmatite: quartz core surrounded by microcline-plagioclase
-Garnets (upto 8mm) in margins and as halo around pods for several cm's. Looks like an in situ miarolitic type of development, not a dike
-Sample on tape for Xray ID of waxey grey-green mineral in pod
May be altered feldspar

Xray ID: xenotime

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
phenocryst plagioclase 0.0 0.0

Minerals of Note
Mineral Abundance (%)
garnet

Rock Number: 2

Rock Type: diabase
Descriptors:
Molson dike
chill margin present
2.2 metres wide

Field Description:

-chill margins and coarser core that has large pyroxenes and probable magnetite-serpentine pseudomorphs of olivine

Minerals of Note
Mineral Abundance (%)
pyroxene
olivine
serpentine

Manitoba Geological Survey, 2017