Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    84     STATION    5665
EASTING   568481     NORTHING   6049054     ZONE   14     DATUM   NAD83
Date of mapping    07/26/1984

STRUCTURAL DATA

Layering:
Layering type Strike Dip top Direction
bedding 311 54

Planar Structures:
Structure type Strike Dip Separation
schistosity 251 76

Linear Structures
Type Plunge Azimuth
rodding 53 43

PETROLOGIC DATA

Rock Number: 1

Rock Type: greywacke
Descriptors:
bedded
mafic

Field Description:

-hornblende rich seds. as to east with some ampb. horizons
-patchy feldspathic alteration

Minerals of Note
Mineral Abundance (%)
hornblende
garnet

Rock Number: 2

Rock Type: sandstone
Descriptors:
massive
psammitic

Field Description:

-brownish grey weathering psammite to west of outcrop
-mostly 1 to 2 in massive lush with 10 to 20 cm semi-pelite interbeds
-patchy alteration to feld-HB on 2 to 5 cm scale

Rock Number: 3

Rock Type: pegmatite

Field Description:

-sampled extensivly by Anderson
-part of peristerite group
-not as much plag. as at 5643 dike but still significant
-has BO, some TC, lots of apple green apatite
-a few tiny opaques
-two textural phases--1) coarse plag. rich phaneritic
2) true peg, blacky perthitic microcline in peg-often graphic

Rock Number: 4

Rock Type:

Field Description:

-ALTERATION ZONE
-patchy material as at last with orange - pink garnet and some TL appears constrained to layering-may predate pegs
-appears to be aluminous alteration as amount of free quartz decreases sharply in the alteration patches

Minerals of Note
Mineral Abundance (%)
garnet
tourmaline

Rock Number: 5

Rock Type: tonalite
Descriptors:
massive
leucocratic

Field Description:

-grey white 2 m thick massive intrusion
-intrusive into layering and folded by late foliation
-TL developed along contact with country rock
-pinches out to thin vein and then disappears going east
-relationship to pegs unclear as they don't cross but as it is intruding layering only and is then folded
-I suspect it predates pegs. significantly

Minerals of Note
Mineral Abundance (%)
biotite
tourmaline


Manitoba Geological Survey, 2017