Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    84     STATION    5649
EASTING   568616     NORTHING   6049058     ZONE   14     DATUM   NAD83
Date of mapping    07/23/1984

STRUCTURAL DATA

Planar Structures:
Structure type Strike Dip Separation
schistosity 297 69

Linear Structures
Type Plunge Azimuth
rodding 57 28

PETROLOGIC DATA

Rock Number: 1

Rock Type: greywacke
Descriptors:
bedded
mafic

Field Description:

-pretty much the whole shore is the same grey mottled greywacke siltstone
-the only significant variation are in grain size and mafic content
-bedding is indistinct and highly deformed
-the centre of the outcrop is dominated by a very strange white and beige mottled containing ggrey, felsic rock
-it gen. follows foliation but varies in thick to 1 to 2.5 m.
-it does not appear to be a sed. horizon nor does it look intrusive
-I suspect unit to be greisson type alteration zone
-there appear to be remnant layers and textural remnants of the greywacke in a medium grained, gneissic bearing feld. rich laminated biotite gneiss
-the rock is slightly buggy and contains significant amounts of tourmaline
-the texture of the rock is reminiscent of Snow Lake alteration
-the margin of the greisson is a contact zone varying from 5 to 20 m thick of chlorite feld. amphibole schist
-the alteration zone contains GR as irreg. aggregates as does the contact zone in irregular masses up to 10 cm
-SAMPLE A and B are from the alteration zone
-SAMPLE C from the greywacke 1.5 m south of contact


Manitoba Geological Survey, 2017