THE MANACOUAGAN IMPACT &
There is a 100 km diameter crater in
Manicouagan in Quebec, Canada, dated to circa 214 MYA. In addition, Western
Antarctica is a small continent that appears to have been formed around that
same time. The Manacouagan impact and the location of the newly formed Western
Antarctica could have been antipodal to each other 214 MYA.
are we to make of all of this information? Is this all related to a singular
The impact at Manicouagan occurred approximately 214 MYA. It
created a crater of 100 km in diameter.
The impact object hit right in
the middle of the Canadian shield. There was no water to help abate the force
of the impact on the lithosphere.
Although the impact would have been
on the smallish side (in terms of uplifting a continent at the antipode), this
impact hit solid rock with no mitigating circumstances or any other buffer. The
uplifting of a small continent would be possible.
The small continent
of Western Antarctica would be a probable candidate, especially since the
Standard Theory says that it mostly rose from the sea during the period of 206
MYA and 146 MYA. An actual date of 214 MYA would not be too far away from these
indefinite boundaries, especially for an underlying layer that could become
covered with mudstone (as in the case of New Zealand) or other sedimentary
silt. This process of mudstone accretion would mean that the upper layers would
show a later age than the original underlying rock.
But, if Western
Antarctica was created at and near the antipode of the Manicouagan impact,
where would that creation have been located and where are the "tool marks" that
were left behind?
WESTERN ANTARCTICA'S CREATION &
The short answer to this question is: New
Zealand. But the whole answer is much more complicated than just those two
New Zealand is the visible portion of a much larger structure
called "Zealandia." During periods of its history, almost all of the entire
structure has been below sea level. Occasionally, a portion of Zealandia has
risen up enough to create a significant amount of dry land.
approx. 150 to 115 MYA, there were extremely large volcanic events in the
Zealandia area. Then the volcanism stopped. 50 Subsequent to these
events, the land eroded and then built up again. During its history, glaciation
lowered the sea levels and, due to New Zealand's high southern latitude, caused
glaciers to form. These glaciers eroded the land. Large valleys that appear to
be glacial can be seen in the underwater portions of Zealandia.
MYA, most of Zealandia, with the exception of maybe a few small islands, was
below sea level again. The current rise of New Zealand was created from 24 MYA
to 10 MYA, with some final touches in more recent history.
For our purposes, the important part of this
history relates to the large volcanic events that occurred from 150 MYA to 115
At approximately 214 MYA, the antipode of the Manicouagan impact
would have been somewhat to the north and east (within a thousand miles or so)
of the present day site of New Zealand. It is likely that the impact raised up
a small antipodal continent with an active hotspot. This continent was Western
Antarctica. It is also likely that the Western Antarctica continent was made up
almost exclusively of mafic oceanic crust that rode well below the surface of
the ocean, except for the uplifted leading edge, which would have forced the
subduction of the oceanic crust in front of it.
A look at a relief map
of the area near Zealandia shows the tool marks left behind by this continent
as it moved SSW, approaching Zealandia, moving through the area, and then
swinging to the east as the Coriolis effect influenced its movement.
Western Antarctica is about 2500 miles long. Originally, it probably
stretched from just below Fiji's original location out 2500 miles to the
northeast, but moving to the SSW.
Fiji's original location was not
where it is today. Not only was it located at a different longitude and
latitude because its tectonic plate has moved in the past 214 million years (to
the north and east), but Fiji was not in the same position in relation to the
seamount chain that proceeds from Fiji to New Zealand.
seamount chain (with Fiji at the head of it) was all in a straight line.
However, plate tectonics caused the head area to form its own mini-plate, which
rotated the top of this chain.
The Ministry of Lands and Resources of
Fiji explains that when island arcs are stretched, "they split, initially
forming a rift and eventually a back-arc spreading centre." 46 pg
In the case of Fiji, the stress was so great that the Fiji area
broke off into its own small tectonic mini-plate, as shown in the first page
diagram on their website. 46
Therefore, even though the
seamount chain (headed by Fiji and leading to New Zealand) now is in the shape
of a shepherd's crook, it was originally in the shape of a straight line.
THREE PARALLEL LINES
about 100 miles to the east of the Fiji seamount chain is the Tonga seamount
chain, which runs roughly parallel to the Fiji seamount chain. Another 50 miles
to the east, the Tonga trench runs parallel to the Tonga seamount chain.
All three of these features lead down to New Zealand, where they are
obscured. Exiting south of New Zealand is a trench and an intermittent line of
higher ground that run almost on top of each other. These combined features
continue generally SSW until they reach approximately 60 south latitude, where
they veer to the south and then to the southeast. Then they disappear.
What does all of this have to do with Western Antarctica? These are the
tool marks left behind by that continent on its journey to the South Pole.
The Fiji seamount chain is the result of Western Antarctica's blob
turning slightly to the west as it moved to the south, pushing up a small
amount of land as it passed by.
During this part of the journey, the
hotspot (located on the north side of the continent, near the blob) was moving
in tandem with the continent, but not as fast. As a result, the hotspot was
raising up land with a basalt underlayment on the new continent (similar to the
western mountains in the Indian peninsula from 65 MYA to 60 MYA).
tail of the continent was being forced to follow to the southwest, although the
underlying magma pulled to the west. This action created the Tonga trench as
the tail passed by and pulled to the west.
When the middle of the
offset tail outran the hotspot, the offset bottom tail of the new continent was
too far to the west to continue covering the hotspot. Therefore, the hotspot
started cutting through the Australian plate at that point about 150 MYA (at
the northernmost point of the present New Zealand).
continued cutting through to the southernmost point of the present New Zealand,
when the offset tail of the continent swung over the hotspot again as the blob
turned to the south (from southwest) and then to the southeast (due to the
Coriolis effect) about 115 MYA.
This swinging motion, and some tail
wobble as a result, caused the strangely curved uplifted mountains (as it
passed over the hotspot again) in the tail of Western Antarctica.
Western Antarctica drifted southeast, it collided with Eastern Antarctica. The
leading edge of the Western Antarctica continent became enmeshed with Eastern
Antarctica. These two enmeshed continents continued to sink towards the South
The hotspot continued on its path to the southern polar region,
becoming uncovered at present day Buckle Island and continuing to the
southeast, creating volcanic cones (including Mount Melbourne) on the way to
its present location at Mount Erebus on the Ross Ice Shelf of Western
The glaciation around Antarctica during the past 200
million years erased most tool marks in the basin area around Antarctica.
THE SURPRISING TONGA TRENCH
One of the strongest indicators for the scenario that I have presented is the
surprising nature of the Tonga Trench. The Tonga Trench is a subduction zone,
which caused the formation of the Tonga Islands and the collection of seamounts
that lead down to New Zealand.
However, the Tonga Trench is not a
typical subduction trench. It is unusual in two respects:
1. It did not start subducting until 43 MYA (up
until then, the movement was parallel). Other subducting systems (Japan, the
Americas) have been subducting for over 200 million years.
The article also notes:
2. The type
of subduction is also unusual. The Tonga Trench has a shallow subduction
mechanism as opposed to the deep subduction mechanism that is typical. An
article entitled "Tonga Slab Deformation: The influence of a lower mantle
upwelling on a slab in a young subduction zone" by Michael Gurnis, Jeroen
Ritsema, Hendrik-Jan van Heijst and Shije Zhong in Geophysical Research
Letters, August 15, 2000 explains:
"The contrast between Tonga-Kermadec and both
Japan and South America is striking. Tonga-Kermadec has a transition zone
structure dominated by high shear velocities immediately atop a large-scale low
velocity anomaly in the lower mantle. Within both the Japan and South American
subduction zones, high shear velocity structures in the transition zone
continue deep into the mantle." 47 pg 2373
"In long-lived subduction systems the lower
mantle tends to pull slabs down while in Tonga the lower mantle pushes upward."
47 pg 2375 So, what does all of this mean? It means
that the Tonga Trench is now subducting in spite of itself. The only reason
that it subducts at all is because there is a deep trench and, over time, this
inevitably leads to at least some subduction.
However, the Tonga Trench
is not a structure that was created by subduction pressures. In fact, it
actively resists subduction. Therefore, the Tonga Trench must have been created
in some other manner
such as resulting from the creation and passing of
a continent like Western Antarctica.
EXPLAINING NEW ZEALAND
geological history of New Zealand (and Zealandia) is unusual. It is also
well-explained by the theory presented in this chapter.
Standard Theory can glibly explain New Zealand and Zealandia as a result of its
location on a plate boundary and the sinking of a small continent (Zealandia)
after it separated from Antarctica, the Standard Theory doesn't explain
important corollary questions that are raised by this standard explanation.
These questions are:
1. SINKING - Why did the Zealandia continent
sink? How come we don't have sunken continents in lots of other places?
The Standard Theory does
not have any good answers for these questions. However, the theory of an
uplifted and moving Western Antarctica and its follow-on hotspot answers these
2. WHY FORM JUST NEW ZEALAND? - If the plate boundary is such a big
deal, why is the formation of land limited to just the New Zealand area? Why
wasn't land created along the plate boundary to the north of New Zealand or to
the south of New Zealand?
3. PLATE BOUNDARY - Why is this plate
boundary so peculiar (see above discussion of the Tonga Trench)? Why would this
plate boundary be so inactive above New Zealand and then so active (but not
necessarily subductive 49 ) when it hits New Zealand
inactive after it passes New Zealand?
In effect, New Zealand and Zealandia are the
creations of a slot that was cut into the lithosphere of the Australian plate
by Western Antarctica's hotspot when it was uncovered and traveled under that
portion of the Australian tectonic plate. The slot began when the hotspot
emerged from under the middle of Western Antarctica's tail, because the lower
tail was offset. The slot ended when the lower tail again covered the hotspot
when Western Antarctica turned to the south and southeast due to the Coriolis
effect, and the offset tail was forced to the west.
NEW ZEALAND GEOLOGICAL HISTORY
Zealandia has been a shallow continental shelf area for most of its
existence. As such, it built up great amounts of sedimentary mudstone called
"Greywecke" over millions of years of continental runoff and marine deposition.
Zealandia has experienced three separate instances of orogeny
(uplifting). The first orogeny occurred about 350 MYA, called the Tuhua
orogeny. It uplifted some of the undersea land in Zealandia (a small amount of
which is still dry land today) through volcanic means and perhaps some folding
of the sedimentary areas. 51
This land was later eroded
away, leading to more deposition of mudstone. From 150 MYA to 115 MYA there was
a large amount of volcanic activity, which was the source of the second
orogeny, called the Rangitata orogeny. 50 This time period covers
the time when the Western Antarctica hotspot cut through the lithosphere at the
New Zealand location. This gash in the lithosphere created a permanent weakness
that could respond to nearby mantle pressure.
Once again, the land was
eroded by sea, weather and glaciation. By 35 MYA, very little dry land was
left. Starting around 30 MYA 52 and picking up steam from 22 MYA to the present
day, the Kaikoura orogeny has uplifted New Zealand to its present situation.
During the past several million years, erosion
and sedimentary deposition have been the major factors in building up the
below-sea-level expanse of Zealandia. As far as I can tell, Zealandia never
its above-sea-level land eroded away and was later rebuilt through
volcanic action in the slot that was cut into the lithosphere.
believe that glaciation was a major factor in eroding and spreading out the dry
land to expand the footprint of Zealandia. On both sides of the slot, Zealandia
shows what look to be large glacial valleys that led to what would have been
sea level during the ice ages (when the sea level was, necessarily,
THE MANICOUAGAN SMOKING GUN
Let's review what we now have for the elements of a smoking gun for the
1. CRATER - There is a 100 km diameter crater at
Manicouagan in Quebec in Canada that is dated to circa 214 MYA. This sequence leaves
us with a very complete picture of the formation and movement of the Western
Antarctica continent and hotspot, based upon the antipodal effects of the
impact at Manicouagan.
HOTSPOT - There is evidence of the hotspot cutting a slot at New Zealand 150 -
115 MYA and raising up mountains on the Western Antarctica continent. There is
later evidence of a line of volcanoes going from Buckle Island to Mount Erebus
in the Ross Ice Shelf of Antarctica, continuing the path of the hotspot, which
is an anchored characteristic, not so susceptible to the pull of the Coriolis
effect. At present, the hotspot is located at Mount Erebus.
WITH A TAIL - We have Western Antarctica, which was supposedly raised from the
sea in the vague time frame of 206 - 146 MYA. If the volcanism began 214 MYA,
then sediment deposition from 206 MYA to 146 MYA would make sense.
CONTINENTAL MOVEMENT - We have the tool marks of the Fiji seamount chain, the
Tonga seamount chain and the Tonga Trench. We also have the New Zealand hotspot
slot and the continuation of the pushed up land (but below the surface) and the
trench as the Coriolis effect changed the direction of the continental
5. TANDEM MOVEMENT - We have the orogeny on Western
Antarctica, the hotspot slot at New Zealand, the strange curved mountains at
the end of the tail of Western Antarctica, the continuing trail through Buckle
Island and the line of volcanoes (including Mount Melbourne) that lead to Mount
Erebus, where the hotspot is located today.
The only thing missing is a major extinction!
The impact occurred 214 MYA. The closest major extinction was the
Triassic, which occurred 202 MYA.
However, there was a minor extinction
(only about 18% of species were eliminated) that occurred right around 214 MYA.
It seems that we can't blame Western Antarctica for the Triassic extinction.
Apparently, the result from this smaller (compared to Chicxulub) impact was not
enough to set off a major extinction. A minor extinction will have to do.