Chapter nine of this book provides a
sketchy look at the relationship between the creation of Western Antarctica and
the Triassic extinction, both of which occurred approximately 200 MYA.
The purpose of Appendix II is to
provide additional exploration of the actions of cause and effect involved in
these two events.
Chapter nine notes that there is a 100
km crater in Manicouagan in Quebec, Canada, dated to circa 214 MYA. The hotspot
is unexplained. The vast lava flows of the Central Atlantic Magmatic Provinces
(CAMP) are mostly occurring at around 200 MYA, along with the Major Triassic
extinction event around that time.
In addition, Western Antarctica is a
small continent that appears to have been formed about 200 MYA.
So, what are we to make of all of this
information? Is this all related to a singular event?
Probably not. The impact at Manicouagan
has been nailed down to 214 MYA plus or minus 1 MYA. The Triassic/Jurassic
boundary has been dated to 202 plus or minus 1 MYA. These dates have been
radiometrically established. There is too much time difference between the
events.44
SO, WHAT DID
HAPPEN?
It appears that there are two separate
events:
1. The Manicouagan impact and
the formation of Western Antarctica approx. 214 MYA.
2. The Siberian
collision and the formation of the Central Atlantic Magmatic Provinces (CAMP)
and the Triassic extinction approximately 202 MYA.
THE MANICOUAGAN IMPACT &
WESTERN ANTARCTICA
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 certainly 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.
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
& JOURNEY
The short answer to this question is:
New Zealand. But the whole answer is much more complicated than just those two
words.
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.
From 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 glacial valleys can be seen in the underwater
portions of Zealandia.
By 35 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.45
For our purposes, the important part
of this history relates to the large volcanic events that occurred from 150 MYA
to 115 MYA.
At approximately 214 MYA, the
Manicouagan impact would have been somewhat antipodal to 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.
A look at a relief map of 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 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.
Originally, this 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
3
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
Located 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).
The 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).
The hotspot 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.
As Western Antarctica drifted
southeast, it collided with Eastern Antarctica. The leading edge of the Western
Antarctica continent became enmeshed with Eastern Antarctica. The southeastern
motion of the Western Antarctica continent was therefore all transferred to the
tail, which swung around to its present position.
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 Antarctica.
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.
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
The article also notes:
It goes on: "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 resuting from the creation and passing of a
continent like Western Antarctica.
EXPLAINING NEW ZEALAND
The geological history of New Zealand
(and Zealandia) is unusual. It is also well-explained by the theory presented
in this appendix.
Although the 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?
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
and then
inactive after it passes New Zealand?
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 questions nicely.
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.
The antipodal hotspot theory would
hypothesize that the Chesapeake Bay impact, which created a hotspot that
started running down the southeastern face of Australia 35MYA, was the primary
cause of the Kaikoura orogeny. As the hotspot moved down the face of Australia,
getting closer to New Zealand, the weakened New Zealand slot in the lithosphere
would have relieved some of the pressure by exhibiting volcanism. It should not
be surprising that, as the hotspot weakened but still drew closer to New
Zealand, the North Island of New Zealand saw most of the volcanic action.
53
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
sank
its above-sea-level land eroded away and was later rebuilt through
volcanic action in the slot that was cut into the lithosphere.
I believe that glaciation was a major
factor in eroding and spreading out the dry land to expand the footprint
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, substantially lower).
THE MANICOUAGAN SMOKING GUN
Let's review what we now have for the
elements of a smoking gun for the Manicouagan impact.
1. CRATER - There is a 100 km diameter
crater at Manicouagan in Quebec in Canada that is dated to circa 214 MYA.
2. 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.
3. BLOB WITH A TAIL - We have Western
Antarctica, which was supposedly raised from the sea in the vague time frame of
206 - 146 MYA
close enough.
4. 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 movement.
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.
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.
The only thing missing is a major
extinction!
The impact occurred 124 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.
THE TRIASSIC EXTINCTION
So, now we have a major extinction
without an impact site to blame it on.
Does this mean that impacts are not the
cause of all major extinctions?
The answer is: yes and no.
There was a huge magmatic event at
virtually the same time as the Triassic extinction approx. 202 MYA. Called the
Central Atlantic Magmatic Province (CAMP), this region contains 300,000 square
kilometers of extrusive basalts that occurred around 200 MYA. Moreover, "dikes
and sills of CAMP that fed the basin basalts also occur across 11 million
square kilometers within four continents, centered upon but extending far
outside of the initial Pangaean rift zone" according to J. Gregory McHone.
54
The CAMP is located along the rift
line that occurred between North America and Europe as Pangaea began to break
up about 200 MYA. There are also substantial basalt intrusions and deposits
along the African and South American coasts, which lead most geologists to
believe that there was rifting between those two continents, also (I do not
believe that there was any rifting here, because the South American continent
had not yet been created
see Appendix III. In my view, the CAMP that was
located in and near Africa and northern South America was a result of the
creation of the Eastern North American Plate ... see Appendix IV).
In the last 30 years, the idea of a
CAMP has gone from an interesting theory to a pretty well proven reality. The
ages and types of magmatism are now proven to be very similar all along this
huge area. Initially, it looks to be a stretch to conclude that all of these
magmatic events are part of the same mega-event. But now this theory is pretty
well accepted.55,56,57,58
The small difference in the cited dates
(202 MYA for the Triassic extinction and 200 MYA for the CAMP) would be right
at the limit of the stated margin of error, but it could also mean that there
are some CAMP sites that are just slightly older that have not yet been sampled
or have not been sampled in the oldest areas of those sites.
J.G. McHone notes that, although some
geologists might favor a plume theory for the cause of this magmatism, there is
no evidence to support this possibility, nor is there a hotspot that is a
likely culprit. It appears that this magmatism was a result of plate tectonic
action. He says, "Continental rifting was active 25 m.y. before and after the
magmatic event, during which rifting and magmatism evolved into a spreading
ocean crust." 58
Interestingly, all of the conversation
seems to be about the CAMP and their relation to the Triassic extinction. No
one speaks to the cause of the CAMP, other than to say that they are related to
the breakup of Pangaea.
The only explanation for the breakup of
Pangaea seems to be "rifting," caused by tectonic forces.
A DIFFERENT EXPLANATION
Although I agree with the CAMP theory
in general, I believe that there are two important differences between this
theory as stated and what actually occurred. These differences deal with the
cause of the breakup of Pangaea and the relationship between South America and
Africa.
As seen in maps of the CAMP, the
magmatic activity of the CAMP stopped somewhere around the equator. It did not
go farther south. This probably means that the rifting stopped at that point.
57 pg 2
If the reason for the CAMP was the
breakup of Pangaea, then there is no good reason for the CAMP to suddenly stop
halfway down the coast of Africa. It was already halfway down the Gondwana area
of Pangaea. Why stop there?
I believe that the reason why the CAMP
stopped around the equator had to do with the fact that it relates only to the
creation of the Eastern North American Plate.
I believe that the South American
continent was not created until 132 MYA (see Appendix III). Therefore, models
of the CAMP that show the effects on South America are not accurate. South
America did not exist at that time.
When South America was uplifted as a
continent 132 MYA, it contained some of the CAMP material (Amazonia) in its
northern reaches, because that material happened to be located there at the
time it was uplifted. But there was no rifting related to South America until
it was created 132 MYA and given a strong westward impetus. Up until then, the
Pacific plate was being subducted by Africa near its southern end while being
subducted in the opposite direction by the Eurasian plate on its northern end.
This impossible situation forced the creation of the Nazca plate, which was
initially being subducted by Africa but is now being subducted by Africa's
proxy, South America.
While these important differences need
to be pointed out, they do not change the basic premise of the CAMP and its
relation to the Triassic extinction.
It appears quite probable that the
Triassic extinction was caused by the CAMP. However, the CAMP were caused by
the impact effects of an impact that created Eastern North America. More about
this in Appendix IV. Therefore, a cosmic impact was the root cause of the
Triassic extinction.
SUMMARY
This appendix presents two different
propositions with evidence supporting both of them:
1. MANICOUAGAN & WESTERN ANTARCTICA
- This appendix presents a complete outline of the cause and effect
relationship between the impact at Manicouagan 214 MYA and the creation and
movement of the Western Antarctica continent. However, this appendix also
refutes the idea that this scenario is responsible for the Triassic extinction.
We have learned that a sizeable cosmic impact, a continental uplift and a flow
basalt hotspot are not sufficient to cause a major extinction
a minor
one, yes, but not a major one.
2. CAMP & THE TRIASSIC EXTINCTION -
This appendix presents and agrees with the current data that shows that the
CAMP were a major cause of the Triassic extinction. However, as we will see in
Appendix IV, the CAMP are the result of an impact that thrust up Eastern North
America.". 44, 50, 45, 46 pg 3, 46, 47 pg 2373, 47 pg 2375, 47 pg 2375,
49, 51, 50, 52, 53, 54, 55, 56, 57, 58 58, 57 pg 2
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