Cross Lake Project (1983-86)
Geologist P.G. Lenton
Year 83
STATION 5187
EASTING 573569
NORTHING 6056802
ZONE 14
DATUM NAD83
Date of mapping 08/05/1983
STRUCTURAL DATA
Structure type | Strike | Dip | Separation |
---|---|---|---|
schistosity | 45 | 87 |
Rock Number | Type | Width (m) | Strike | Dip |
---|---|---|---|---|
0 | diabase | 0.25 | 217 | 88 |
-several photos of hydrothermal alteration of granite
PETROLOGIC DATA
Rock Number: 1
-grey weathering mottled intrusive, possibly derived from a marginal phase of the granite
-has a strange mottled appearance caused by irregular anastomosing web work or coarser quartz, feldspar, biotite and chlorite
-these coarse areas resemble the epidotized margins of alteration veinlets in the granite
-my impression is that this rock has undergone considerable hydrothermal alteration, probabl as a late magmatic feature related to the de-gassing of the pluton
-there are textural remnants that resemble the porphyritic nature of the granite but converted to fine grained quartz, feldspar, chlorite, epidote leaving only vague outlines of pre-existing phenocrysts
Sample 1B - alteration of granite by hydrothermal vein system
Mineral | Abundance (%) |
---|
muscovite |
magnetite |
PHOTOS
Photo of alteration in margin of granodiorite.
Detail of alteration.
Alteration may be a hornfels effect.
Manitoba Geological Survey, 2017