Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    83     STATION    5099
EASTING   573555     NORTHING   6040306     ZONE   14     DATUM   NAD83
Date of mapping    07/07/1983

STRUCTURAL DATA

Planar Structures:
Structure type Strike Dip Separation
gneissosity 72 79
fault 298 77

Fault is a 20 cm brecciated mylonite

PETROLOGIC DATA

Rock Number: 1

Rock Type: two component schlieric gneiss - intimate mixture of 2 major units
Descriptors:
cataclastic

Field Description:

-Base rock is augen-granodiorite, highly schlieric
-early pegmatite injection is near totally homogenized by shearing
-schistosity is highly erratic, but gneissosity is planar
-biotite shows moderate segregation

Minerals of Note
Mineral Abundance (%)
hornblende

Rock Number: 2

Rock Type: amphibolite
Descriptors:
layered
hornblende - diopside bearing

Field Description:

-highly varied inclusions of obvious volcanic source appear to be dominantly flow derived with a minor source from volcanic sediments
-highly brecciated and deformed
-much of the schlieric matierial is hornblendic and probably derived from the amphibolites

PHOTOS


General texture of the augen grandiorite showing the intense fabric.


Mylonite cutting the old granodiorite with brecciated and rotated fragments in the ultramylonite.


Layered amphibolite reduced to agmatite then schollen screens in the old augen grandiorite


Manitoba Geological Survey, 2017