Cross Lake Project (1983-86)


Geologist    P.G. Lenton     Year    84     STATION    5590
EASTING   580232     NORTHING   6062701     ZONE   14     DATUM   NAD83
Date of mapping    07/15/1984

STRUCTURAL DATA

Layering:
Layering type Strike Dip top Direction
bedding 40 67

Planar Structures:
Structure type Strike Dip Separation
cataclastic foliation 358 70

PETROLOGIC DATA

Rock Number: 1

Rock Type: basalt
Descriptors:
massive
andesitic

Field Description:

-south half of island mafic volcanics
-pillow unit on south, massive up against felsic
-massive unit basaltic andesite with quartz carbonate veining
-aphyric
-weathers slightly rust brownish black
-flows appear to be around 3 to 4 m thick

Minerals of Note
Mineral Abundance (%)
calcite

Rock Number: 2

Rock Type: basalt
Descriptors:
pillowed
andesitic

Field Description:

-probable mixture of pillowed and pillow breccia basaltic andesite with 25 to 1000 cm massive flows
-sheared and heavily veined with carbonate that weathered out leaving an irregular pitted surface

Minerals of Note
Mineral Abundance (%)
calcite
garnet

Rock Number: 3

Rock Type: siltstone
Descriptors:
laminated
felsic

Field Description:

-delicate 1 to 2 mm laminations in a siliceous grey to beige weathering siltstone
-may be a reworked rhyolite tuff but is aphyric and purely sedimentary as far as I can tell now
-silts and basalt interlayered at contact in 1 to 2 m units going north into massive siltstone unit
-contact zone marked by extensive gossan development (sample 3B)

Minerals of Note
Mineral Abundance (%)
garnet


Manitoba Geological Survey, 2017