Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 86 STATION 6494
EASTING 567105 NORTHING 6043294 ZONE 14 DATUM NAD83
Date of mapping 07/28/1986

STRUCTURAL DATA

Layering:
Layering type | Strike | Dip | top Direction
inclusion layering | 224 | 77 |

Planar Structures:
Structure type | Strike | Dip | Separation
cataclastic foliation | 337 | 70 |
schistosity | 342 | 47 |

Dikes and Sills:
Rock Number | Type | Width (m) | Strike | Dip
0 | Molson dike | 0.00 | 224 | 57

-a weak 050 fracture direction
PHOTOS
1 -drainage channel, PX cummulative layering
2 -slump faulting, cummulative bands
3 -general convolute layering
4 -gravitational settling producing drop fold and minor scouring
5 -large scale layering
6 -cross view with Kim at central cummulate zone and boat at footwall contact
7 -footwall contact
8 -detail of PX-PORT footwall rock

PETROLOGIC DATA

Rock Number: 1

Rock Type: multi-component schlieric gneiss
Field Description:

-dominant rock type is the coarse, slightly PORT-CWB-TNLT
-extensivly intruded by old grey GRDR-PORT and young grey massive GRDR
-there is 2 generations of old peg. apatite that predate the massive grey GRDR and one generation that post-dates it
-the rock is generally HM-especially on joint surfaces and has a bleached appearance several metres below the Molson

Rock Number: 2

Rock Type: diabase
Descriptors:
NORT
Field Description:

-major Molson dike around 35 m exposed semi-continuously from the footwall up
-the last exposure of section is in very coarse PX-PG cummulatively layered rock
-this probably indicates the dike of the full width of the swampy grasslands to the NW with an approximate thickness of 75 to 80 metres
-this dike has unusual textural features, not encountered in other dikes on the lake
-the footwall contact is a near aphanitic gabbro or NORT with 25% cm-sized euhedral PX's, probably clino-PX now altered to black HB (see sample A taken right at contact, and sample B)
-there is a rapid upward progression into a medium grained MG-bearing, probably NORT unit, and then into PX-PG cummulative rocks
-the grain size, spacing and thickness of cummulative layers continues to increase to the limit exposure, probably indicating <.5 of dike is exposed
-at limit of exposure,-NORT grain size is about 3 mm, and layering is on a 5 to 10 cm scale
-sedimentary structures in the layered sequence are diverse including slump folding, slump faulting, scours, convolute lamination and some X-bedding
-sample C is from the layered section
--NB: in cummulative layered section, gabbro-peg. are common

Manitoba Geological Survey, 2017