Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    83     STATION    5076
EASTING   571673     NORTHING   6039025     ZONE   14     DATUM   NAD83
Date of mapping    06/27/1983

STRUCTURAL DATA

Planar Structures:
Structure type Strike Dip Separation
schistosity 231 81

PETROLOGIC DATA

Rock Number: 1

Rock Type: tonalite
Descriptors:
schlieric or schlieren present
leucocratic
anastomosing vein network
aplitic vein webwork
pegmatite lit
aplite veins/dikes present

Field Description:

-Anastomosing vein network of augen tonalite as previous station
-Heavily intruded by old sheared pegmatite/aplite/fine-grained granite vein networks.
-produces network with local developement of more extensive pods

Rock Number: 2

Rock Type: amphibolite
Descriptors:
massive
gabbroic
occurs as a raft
salt and pepper texture

Field Description:

-salt and pepper gabbroic rock comprising fine grained plagioclase surronding coarser 2-3 mm equant hornblende
-could possibly be volcanic derived but seems a little too massive and featureless - I would prefer to call it and early gabbro intrusive - probably intruded the volcanics
-sample B is odd - looks like a psammite but has little or no quartz - all hornblende-biotite-plagioclase -probably a fine diorite or leuco-gabbro
-Sample C- finer more mafic gabbro

Textural Features
Type Mineral Min. Size Max. Size Abundance (%) Unit
mafic mineral hornblende 2.0 3.0 60.0 mm
groundmass grainsize plagioclase 0.0 1.0 40.0


Manitoba Geological Survey, 2017