Monday, December 24, 2007
Bill Plavac and Peter Russell
Extraction and delivery of Matachewan Porphyry to University of Waterloo by the CCFMS project team
On
November
2,
2007,
four
members
of
the
CCFMS
and
two
local
Matachewan
contractors
set
out
to
extract
several
large
boulders
of
Matachewan
Porphyry
from
a
site
in
the
Bannockburn
Township
near
Matachewan
in
the
Kirkland
Lake
area
of
Ontario.
The
Matachewan
Porphyry
is
made
of
pink
to
cream
rectangular
feldspar
phenocrysts
from
.6
cm
across
to
2.5
cm
(
1/4
to
1
inch)
floating
in
a
dark
grey
to
black
country
rock.
The
Team
arrived
with
backhoe,
float,
blasting
equipment,
diamond
saw,
Pionjar
drill
and
small
tools
ready
for
any
issue
that
might
make
extraction
difficult.
The
backhoe
operator
quickly
went
to
work
and
removed
trees
and
rocks
that
were
in
the
way
of
successful
extraction
of
the
specimens.
After
several
hours
of
work
to
clear
a
way
for
removal
of
the
specimens,
the
first
large
piece
was
successfully
removed
from
the
outcrop.
The
.90
m
by
.90
m
by
1.2m
(4
ft
by
4
ft
by
3
ft)
piece
weighing
several
tonnes
was
destined
for
the
University
of
Waterloo.
Several
hours
later
four
more
large
pieces
of
Matachewan
Porphyry
were
successfully
removed
from
the
outcrop
and
loaded
onto
a
flatbed
truck
with
the
backhoe.
They
were
transported
to
the
town
of
Matachewan
ready
for
loading
on
November
5,
2007
on
a
transport
truck
headed
for
Waterloo
and
Peterborough.
On
November
9,
2007,
the
University
of
Waterloo
specimen
was
unloaded
and
planted
in
the
university’s
Rock
Garden.
Members of the Team were:
CCFMS:
Bill
Plavac,
Doug
Dingeldein,
Bob
Beckett,
John
Calder
ON
SITE:
JP
Boucher,
Gerard
Bernatchez
Matachewan Porphyritic diabase
To
begin
the
process
of
dyke
formation
the
Canadian
Shield
were
subjected
to
stresses
as
a
mantle
plume
of
molten
magma
1000
km
in
diameter
pushed
up
against
the
brittle
crust
causing
radiating
cracks
to
appear.
Mantle
plumes
are
formed
as
hot
rock
from
the
mantle
moved
upwards,
partly
melting
when
they
reach
shallow
depths
in
the
Earth’s
crust.
The
plume
pushed
up
against
the
crust
centered
north
of
Barrie,
Ontario,
forming
cracks
trending
northwest.
These
radiating
cracks
filled
with
diabase
and
other
volcanic
rocks
from
the
reservoirs
below.
Fractional crystallization
The
magma
in
the
reservoirs
interacted
with
rocks
forming
the
magma
chamber
to
produce
rocks
of
different
chemistry.
As
the
magma
cooled
some
minerals
started
to
crystallize.
In
this
rock
large
feldspars
grew.
This
magma
then
erupted
and
formed
the
porphyritic
rocks
such
as
our
diabase.
As
the
crystals
formed
and
were
removed
from
the
magma,
the
chemistry
of
the
liquid
changed
and
smaller
crystals
grew.
This
process
is
called
fractional
crystallization.
The
dykes
on
the
Matachewan
area
are
approximately
20m
wide
and
are
about
700
to
800
kilometres
long.
Dykes
forming
today
on
Iceland
with
a
width
of
one
metre
move
along
the
fracture
at
about
one
kilometre
and
hour.
The
Matachewan
dykes
may
have
taken
a
month
to
flow
along
the
entire
length
of
the
swarm.
As the lava flows into the fractures forming the dykes the lava cools against the surrounding rocks forming chilled margins. This example is from the Isle of Skye, Scotland.
References
Fractional
Crystallization
http://www.earth.northwestern.edu/pe
ople/seth/demos/FRAC/frac.html