Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 83 STATION 5005
EASTING 572309 NORTHING 6039746 ZONE 14 DATUM NAD83
Date of mapping 06/18/1983

STRUCTURAL DATA

Planar Structures:
Structure type | Strike | Dip | Separation
cataclastic foliation | 69 | 71 |

Linear Structures
Type | Plunge | Azimuth
mineral lineation | 0 | 0

-pitch 56 degrees to west in foliation
-quartz aggregates elongation
-photos of augen potassium feldspar and rootless intrafolial folds
-all minor folds are Z

PETROLOGIC DATA

Rock Number: 1

Rock Type: tonalite
Descriptors:
cataclastic
biotite - hornblende bearing
Field Description:

-Cataclastic texture largely annealed, probably by Hurdsonian overprint
-Layered gneissosity produced by variations in mafics.
-Original rock was probably highly intruded by pegmatite as large (1-5 cm) potassium feldspar - quartz augen are common
-Mafic schlieric zones appear to have hornblende + epidote or diopside and are probably derived from mafic volcanic
-extensive boudinage of schlieric layers
cataclasis largely annealed

Minerals of Note
Mineral | Abundance (%)
chlorite

Rock Number: 2

Rock Type: basalt
Descriptors:
pillowed
rock is an inclusion
Field Description:

Boudinage
-Schlieric margins, partially digested

Minerals of Note
Mineral | Abundance (%)
hornblende
epidote
diopside

PHOTOS

Sheared augen granodiorite with rootless intrafolial Z folds and extreme flattening. Note the late cleavage at a shallow angle to the main shear plane.

Detail showing boudinage of quartz-microcline pegmatite and rotation of large microcline crystal.

Manitoba Geological Survey, 2017