APPENDIX II
WESTERN ANTARCTICA & THE TRIASSIC EXTINCTION

   

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