Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 84 STATION 5589
EASTING 580461 NORTHING 6062647 ZONE 14 DATUM NAD83
Date of mapping 07/13/1984

STRUCTURAL DATA

Planar Structures:
Structure type | Strike | Dip | Separation
schistosity | 275 | 78 |

PETROLOGIC DATA

Rock Number: 1

Rock Type: conglomerate
Descriptors:
felsic
Field Description:

-massive unsorted, ungraded units comprising angular fragments of rhyolite ranging from granule to 10 cm pebble
-they have moderate sphericity and low rounding
-there are two layers separated by 1.5 m of PILL BSLT
-the western layer is 90% clasts of quartz phyric RYLT in a FLSC matrix
-the eastern layer is 75% quartz phryic RYLT in an intermediate composition HB bearing matrix
-the rock is slightly sheared as discrete seams of mylonite without producing a general flattening
-the whole outcrop is folded in a series of tight Z folds with an easterly plunge
-some clasts seem to have spherical or radial structures possibly due to devitrification
-however I believe this to be a reworked feldic deposit not a pyroclastic
-it may represent two separate mass flows

Minerals of Note
Mineral | Abundance (%)
garnet

Rock Number: 2

Rock Type: basalt
Descriptors:
pillowed
Field Description:

-pillow sizes average 15x40 cm
-pillows are amygdaloidal with black hornblendic selvages
PHOTOS
1 -pillow basalt
2 -a feldsic matrix unit up to the west
3 -" " " " " " " " " "
4&5 -general view of hornblendic matrix to the west
6 -clast detail of eastern unit
7 -clast detail of clast in eastern unit with radial structure
8 -clast detail in western unit
9 -folded contact between BSLT and western unit

Minerals of Note
Mineral | Abundance (%)
garnet

Manitoba Geological Survey, 2017