Stops Of Interest: BURIN PENINSULA
- Roches moutonnées at Sandy Harbour River
- Carboniferous rocks, Terrenceville
- St. Lawrence fluorite
1. Roches moutonnées at Sandy Harbour River
Evidence of glacial ice movement often appears
as bedrock sculpture, in addition to the more commonly seen striations and grooves. An
example of such sculpture may be seen in a small gravel pit on the south side of Route 210,
1.4 km east of Sandy Harbour River (1.6 km west of Long Pond Brook). Park on the
shoulder and walk along the short access road.
The rounded humps of Late Proterozoic volcanic rock are known as roches
moutonnées or "sheep rocks" because from a distance a group of them look like sheep in a
field. The rounded end facing you is the "up-ice" end; the "down-ice" end is angular, where
freezing and thawing have broken off blocks of rock. If you run your hand over the smooth
part, you will feel the grooves pointing in a southeasterly direction.
2. Carboniferous rocks, Terrenceville
Carboniferous rocks are rare in the Eastern Zone, but at
Terrenceville, a small slice of Carboniferous sedimentary rock has been protected from
erosion by downfaulting.
To view these interesting rocks, drive to Terrenceville and continue on the main road
southwesterly until it ends along the shore. Walk along the beach and observe the large
blocks that have fallen to the beach as the cliff has been eroded by wave action.
These red conglomerates, sandstones and shales were mainly deposited onshore. Note
the great variety of rock types represented by the pebbles red and green volcanic rocks,
sedimentary rocks, white quartz and granite. Some pebbles are rounded, showing that they
are well travelled, but many are quite angular, suggesting that their source area was close by
and was being eroded rapidly.
In the finer grained beds, you may see some fossil plants consisting of twigs and
branches. The sandstone contains ripple marks and crossbedding.
3. St. Lawrence fluorite
Fluorite,
also known as fluorspar, was mined at St. Lawrence from 1933
to 1978 mining history. To see fluorite in one of the
veins, stop on Route 220 just east of the town of St. Lawrence, 0.6 km west of the road to
the telecommunication towers, at a roadcut in pink St. Lawrence granite. The Church vein
is partly exposed on the south side of the road, below the easterly power pole. Purple,
yellow, red and brown fluorite in vugs, breccia or banded veins may be collected from the
wall, from debris below it or from above the rock cut, where digging for power pole anchors
has exposed blocks of vein material. Fluorite occurs as cubic (six-sided) or octahedral (eight-sided) crystals, or as granular masses.
The veins are related to the granite and formed in shrinkage cracks during the last
stages of cooling of the granite magma during the Devonian.
This series of web pages provides an introduction to the publication
below, which can be ordered from the
Geological Association of
Canada 
Newfoundland and Labrador Traveller's Guide to the Geology
Edited by: S. Colman-Sadd and S.A. Scott, 91 pp. + map, 1994
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