Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 84 STATION 5587
EASTING 580115 NORTHING 6062648 ZONE 14 DATUM NAD83
Date of mapping 07/13/1984

STRUCTURAL DATA

Layering:
Layering type | Strike | Dip | top Direction
bedding | 293 | 82 |

Planar Structures:
Structure type | Strike | Dip | Separation
schistosity | 281 | 74 |

-tops probably NE but uncertain
PHOTOS
1 large fragment of laminated tuff in MAFC CGLM
2 75 cm laminated MAFC wacky at base of GRCK section
3 delicately laminated DCIT tuff below GRCK
4 general view of contact between DCIT and GRCK
5 general view of Deb writing notes
6 angular fragments of DCIT in PBBL GRCK
7 general view of DCIT (massive)
8 close up of massive DCIT
9 tuffacious layer within the GRCK
SAMPLES
1A MASS DCIT with MAFC segregations
1B MASS DCIT near top of unit
1C laminated tuff at top of DCIT
2A&B MAFC CGLM with DCIT clasts
2C laminated MAIC mudstone at base of GRCK's
see photo #2

PETROLOGIC DATA

Rock Number: 1

Rock Type: dacite
Descriptors:
aphyric
Field Description:

-beige weathering, grey on fresh surface, appears to be massive with no layering
-there is an odd mafic segregation at 1 to 2 mm size distributed uniformly
-this may indicate a pyroclastic origin as these may be devitrified glass fragments
-this massive fine grained unit is capped by a dense cherty textured segment overlain by up to 10 cm of fine laminated silty tuffs
-the tuff is overlain by a dark greenish black lithic GRCK with pebbly horizons containing dacite clasts

Rock Number: 2

Rock Type: greywacke
Descriptors:
pebbly
mafic
Field Description:

-unknown thickness of well bedded GRCK and MAFC matrix supported CGLM
-pebbly layers are dominantly breccia fragments of APHY DCIT
-fragments have very low rounding sphericity values
-the pebbly layers also contain irregular blocks up to metres in size of DCIT and laminated DCIT tuff
-bedding surfaces are the very irregular both from deformation and the original paleo topography
PHOTOS
1 -large fragment of laminated tuff in mafic conglomerate
2 -75 cm laminated mafic wacky at base of GRCK section
3 -delicately laminated DCIT tuff below GRCK
4 -general view of contact between DCIT and GRCK
5 -general view of Deb writing notes
6 -angular fragments of DCIT in PBBL GRCK
7 -general view of DCIT (massive)
8 -close up of massive DCIT
9 -tuffacous layer within the GRCK
SAMPLES
1A -MASS DCIT with MAFC segregations
1B -MASS DCIT near top of unit
1C -laminated tuff at top of DCIT
2A&B -mafic CGLM with DCIT clasts
2C -laminated MAFC mudstone at base of GRCK's
-see photo #2

Manitoba Geological Survey, 2017