Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 83 STATION 5153
EASTING 572951 NORTHING 6049039 ZONE 14 DATUM NAD83
Date of mapping 07/20/1983

STRUCTURAL DATA

PETROLOGIC DATA

Rock Number: 1

Rock Type: pegmatite
Descriptors:
large dike
Field Description:

ANDERSON DIKE A-9
-north shore Spodumene Island
Giant spodumene-tourmaline dike
extensive pinch and swell - varies from 85-160 cm in width
general attitude 069/71 dip variable
---Mineralogy:
Spodumene
tourmaline
what I initially thought was saccharoidal albite in the core but turned out to be microfractured quartz core
massive quartz
muscovite
beryl
columbite
apatite with a distinctive aquamarine colour
microcline
-majority of primary block k-feldspar albitized, probably primary muscovite also
-Texture now giant log shaped spodumene crystals and anhedral masses of tourmaline in fine grained microfractured quartz core
-Veins up to 3 cm of bright yellow green flakey lithian muscovite
--Structure
-intrusive into garnetiferous pillow basalts with schistocity and plane of flattening 276/66
3 fabrics in dike:
schistocity at 068/70
cross fracture system 196/75
secondary fracture system 271/84
--Cross section
-amphibolite contact lined with red almandine garnet
3 to 8 mm BORDER ZONE
-fine grained aplite with high concentration of apple green apatite at contact changing to blue green apatite as you move into the dike
- 1/2 to 1 mm tourmaline along the contact
30 cm WALL ZONE
-equant grey albite 1x2 cm and coarse grey bladed albite up to 4 cm
-club shaped tourmaline normal to contact, 5-6 cm, small anhedral microcline crystals
10-20 cm variable UPPER INTERMEDIATE ZONE
-3 to 12 cm black tourmaline
-small 5 -12 cm Spodumene logs
-minor beryl
QUARTZ CORE
-tourmaline up to 30 cm
-30-10 cm spodumines; equant to elongate
-beryl and columbite common
-most columbite in spodumene or near beryl terminations
-local veins of secondary yellow lithium muscovite
-all this surrounded by microgranular fractured quartz
12 cm LOWER INTERMEDIATE
-spodumene concentration at base of core and top of lower intermediate zone
-concentration of 2 cm blocky shaped tourmaline
3cm L. WALL ZONE
-platy grey albite and tourmaline
3mm LOW BORDER ZONE
-aplite and apatite and small tourmalines - similar to upper border zone
SAMPLES
1. ampb at contact
2. ampb 2 m south of contact
3. quartz core microgranular quartz
4. X-ray sample on top arsenopyrite

Manitoba Geological Survey, 2017