Cross Lake Project (1983-86)

Geologist P.G. Lenton Year 84 STATION 5576
EASTING 577975 NORTHING 6059843 ZONE 14 DATUM NAD83
Date of mapping 07/12/1984

STRUCTURAL DATA

Planar Structures:
Structure type | Strike | Dip | Separation
schistosity | 243 | 86 |
fault | 45 | 87 |

-two m shear converts dacite to rusty muscovite schist

PETROLOGIC DATA

Rock Number: 1

Rock Type: breccia
Descriptors:
pillowed
basaltic composition
Field Description:

-greenish black weathering, highly flattened basalt breccia, has both ovoid quartz feldspar segregations and fairly well preserved amygd.
-texural variation is drastic, probably indicating mix of coarse and fine pillow frag, brecciated pillow selvages adn hyaloclastite
-one photo showing general character
-the whole outcrop is extensivly sheared and isoclinally folded in asymmetric S structures
-the contact contains the felsite is irregular i places appearing folded, other places either conformable or intrusive by the felsite

Minerals of Note
Mineral | Abundance (%)
garnet
hornblende
chlorite

Rock Number: 2

Rock Type: feldspar - quartz porphyry
Descriptors:
schistose
DCIT
Field Description:

-PHOTO 2-is the contact between basalt brec. and dacitic FQPP
-PHOTO 3-layer of FQPP either folded or intruded into basalt
-as previous station biege to grey weathering, quartz feldspar phyric dacite or rhyodacite
-slightly more massive contained out the breccia look and a fairly uniform phenocryst and contact
-PHOTO 4-contact between dacite and basalt showing tight unfolding
-the original layering direction was probably near 340 degrees

Minerals of Note
Mineral | Abundance (%)
chlorite

Rock Number: 3

Rock Type: dacite
Descriptors:
fragmental
quartz-feldspar
Field Description:

-fragmental unit probably a flow breccia comprising beige quartz feld. phyric rhyodacite in a matirx of dark brown schisty material, extremely rich in phenocrysts that was probably pumaceous in nature
-this unit shows marked inhomo in phenocryst population
-there are thin layers up to 20 cm thick of fine grained laminated sediment that seems to contain phenocryst frag. and maybe thin tuffaceous horizons
-PHOTO 5 AND 6
-general view of fragments
-PHOTO 7 AND 8
-close up to show variation in phenocryst content
-PHOTO 9
-is general texture of fragmentals
-PHOTO 10 AND 11
-two veins of fine laminated, possibly tuffaceous interbeds
-(end of film roll)
SAMPLES
3A,3B,3C -fragmental unit contains varying phenocryst distribution
-3C may have an exotic clast in it,
-3D is a layer of the laminated felsic tuff

Minerals of Note
Mineral | Abundance (%)
chlorite

Manitoba Geological Survey, 2017