APPENDIX VII
OTHER THOUGHTS & REVISIONS

   

During the several months after publishing the initial version of this book, I have encountered several items that require additional exploration, clarification or revision. The first six appendices deal with the major items of this nature. Appendix VII will deal with the remainder of these items. The items covered in this appendix are:

1. SIDESPIN – What happens when the angle of an impact is off to the side of a full diameter hit?

2. STATISTICAL JUSTIFICATION OF CONTINENTAL UPLIFT – What are the odds of having all of these old craters only showing up in old continents and not in the new land areas of newly uplifted continents? A statistical analysis of the crater data.

3. OTHER POSSIBLE IMPACT, LIP & HOTSPOT CONNECTIONS

A. Hudson Bay & The Kerguelen Plateau

B. The Columbia River LIP & The Yellowstone Hotspot

4. GRAVITY AS A CONTAINMENT VESSEL -- A more in-depth analysis of how gravity contains the effects of an impact at the antipode.

5. CRATONS – Reviewing the lack of examples of stand-alone cratons from the early earth period.

6. THE CARIBBEAN LARGE IGNEOUS PROVINCE

DETAILS ON THE REVISIONS

1. SIDESPIN

When writing about the location of the antipodal hotspot (and the consequent huge area of flood basalt lava) in relation to an uplifted continent, I noted that the hotspot would be located below the center of the main blob area of the new continent.

This location would be the result of the strong rotational momentum of the impact pushing the primary uplifting force beyond the antipodal hotspot point.

However, this scenario does not explain the fact that, in two of the easily identifiable instances of hotspot location (Siberia and India), the hotspot is located off to one side of the new continent. Why would this happen?

The easiest way to characterize this phenomenon is to call it “sidespin.” It is the result of the impact object hitting the earth in such a way that the center line of its force does not go around the largest arc that is possible … it does not trace the largest cross-section that it could.

When an object hits the earth, there are really two different angles involved. I will call these angles the vertical angle and the cross-sectional angle.

A. VERTICAL ANGLE – This angle is the easiest to understand. This angle tells us how close to perpendicular the impact was. A rare zero degree impact would produce no tail during a continental uplift. A 45 degree impact would produce a long tail. A 70 degree impact would likely ricochet off the atmosphere and leave few reminders of its visit.

B. CROSS-SECTIONAL ANGLE – This angle is more difficult to explain. It not only tells us which direction the impact was coming from, but it also tells us how dead center this hit was.

Perhaps an example will help. Let’s suppose that a really big impact occurs exactly at the North Pole at a 45 degree vertical angle. Let’s suppose that the centerline of the force of the impact travels directly down the zero degree line of longitude and passes underneath Greenwich, England.

In this case, the hit would be dead center. The centerline of the force would pass through the largest cross-section of the earth that is possible.

However, most hits are not going to be dead center. There will be a cross-sectional angle away from dead center.

To continue the same example, this time the impact would again come in at a 45 degree angle to vertical, but it will have a cross-sectional angle away from dead center. Therefore, if we are starting at the North Pole, this means that the centerline of the impact force will cross some longitudinal lines and that the centerline of impact force will be directed at some part of the earth that not the South Pole (a dead center hit on the North Pole would see its centerline of force directed at the South Pole).

An off center cross-sectional angle will result in the continent being off center in relation to the antipodal hotspot. The hotspot will be located away from the side of the energy movement of the blob.

2. STATISTICAL JUSTIFICATION OF CONTINENTAL UPLIFT

The theory of continental uplift at the antipode of really big impacts implies that often there is new continental land created from what used to be seabed.

In the last 250 million years, this would be true in Siberia, much of South America (eastern South America was broken away from Africa), Western Antarctica, Eastern North America (the western part of it) and northern India (southern India was ripped out of the Old Australian continent’s upper tail).

If the theory of antipodal continental uplift is correct, then this new land should not contain any new craters that predate its existence (it is possible that there were some old seabed craters, but we should be able to identify them as such).

We know that there are a number of older craters on the older continents. These include North America, Asia (without Siberia), Europe and Australia (both Western Antarctica and Eastern Antarctica are too hard to explore for these features).

As a percentage of total unsubmerged land that can be examined for old impact sites, the newly uplifted continental land might represent about 20%.

Looking at the Wikipedia chart of dated impact craters of 20 km in diameter or more, there are 17 that are more that 250 million years old. 17 None of these craters are located in the newly uplifted continental land.

The possibility that this distribution of old craters just happened to miss these newly uplifted land areas (and that this land was not really newly uplifted land) is small. The probability is 0.8 to the 17th power, or 2.3%. In other words, the table of large impacts tells us that the possibility that the grouping of all the old craters outside of the newly uplifted land has less than a 3% chance of being a random event.

Actually, the random chance level could be shown to be significantly lower than 3% if we were to do some really complicated stratification of the data so that we could include newer impacts and the newer dates for India and South America.

In any case, there are no contraindications for any of this land that is supposed to be uplifted. And there is a significantly less than 3% chance that this uplifted land has no old craters just due to random luck.

If the newly uplifted land was not created through the process of continental uplift at the antipode of a very big impact, then where did it come from?

3. OTHER POSSIBLE IMPACT, LIP & HOTSPOT CONNECTIONS

Self and Rampino propose several Large Igneous Provinces (LIPs) that should be investigated further.

With the exception of the CAMP, I look at LIPs as the likely initial location of a hotspot that is antipodal to a large impact. There are two of these that cry out for further investigation.

A. The Kerguelen Plateau

B. The Columbia River LIP THE KERGUELEN PLATEAU

The Kerguelen Plateau is a LIP that is located just to the north of Antarctica and at approximately the same longitude as India.

The hotspot beneath the Kerguelen Plateau has been moving from the southwest to the northeast. The earliest activity was around 120 MYA. The most recent activity in the northeast is around 35 MYA. 78,79,80

While none of the sources cited above lists an antipodal impact as a possible cause of the hotspot (should we be surprised?), I believe an antipodal hotspot is the cause.

Furthermore, I believe that there is a telltale physical feature that was located antipodal to the hotspot’s beginning location 120 MYA. This feature is Hudson Bay in Canada.

The shape of Hudson Bay is strikingly reminiscent of the shape of the Gulf of Mexico and the Yucatan Peninsula.

Others have looked at the rounded area near the bottom of the bay and have found no sign of a crater. However, the Gulf of Mexico does not have a crater near its rounded areas. The Chicxulub crater is at the top of the “thumb.”

I suspect that there is a crater near the top of Hudson Bay on one side or the other that relates to the Kerguelen Plateau.

COLUMBIA RIVER LIP

The Columbia River LIP is located in and near Oregon and Washington State. It occurred about 16 MYA.

I view this LIP as the large initial eruption of a hotspot. However, I believe that the hotspot involved is the Yellowstone hotspot, the second biggest super volcano in the world.

The Columbia River LIP does not match up with the path of the Yellowstone hotspot. It is too far to the north. However, if the original hotspot happened to be located under the heavy weight of the Rocky Mountains, the basalt lava flows could have leaked out to the north, rather than coming up right at the antipode.

I believe that if someone does the research, they will find a large crater in the South Pacific antipodal to the 16 MYA extrapolated position of the Yellowstone hotspot.

4. GRAVITY AS A CONTAINMENT VESSEL

When I initially wrote about gravity acting as a containment vessel, I did not go into detail. I believe that I need to go into greater detail.

When we think about the impact effects of a bullet hitting a watermelon, we don’t consider the effect of gravity acting as a containment vessel. The reason for this is the fact that a watermelon has a virtually negligible gravitational field. A bullet will blow the watermelon apart. There will be no gravitational effect from the mass of the watermelon.

The planet Earth is an entirely different story. The effect of gravity from the mass of the Earth is huge.

When an object hits the Earth, the effect at the antipode is very much constricted by gravity (unlike a bullet hitting a watermelon, where everything just flies apart).

Gravity affects the results of the impact at the antipode in the following ways:

A. Gravity adds tremendous downwards pressure to the crust of the lithosphere, meaning that it will take a tremendous amount of force to overcome both the force of gravity and the shear strength of the rock in the lithosphere. For this reason, even big impacts can usually only cause magmatic outflows at the weakened antipode, itself.

B. Gravity limits the extent of any continental uplift. If a really big impact has enough force to uplift a continent, gravity will keep operating on this continent as it rises up. As the continent rises, the pressure is partially relieved. When the force of gravity equals the diminished pressure of uplifting, the uplifting will stop. The shear strength of the crust keeps the surface of the continent together.

If the impact force that is transferred to the antipode is great enough to completely overcome both the force of gravity and the shear strength of the lithosphere, then the antipodal area will be blown into orbit (or even space if the force is extreme).

In the past 500 million years, we have seen no impacts that could completely overcome both the force of gravity and the shear strength of the lithosphere.

C. Gravity sets strict limits on the magmatic activity, once the initial conditions have been settled. The combination of the shear strength of the lithosphere and the force of gravity will limit whatever happens next. And what happens next is magmatic activity at the antipode. Gravity and the shear strength of the lithosphere will not allow any more uplifting or expansion of the continent’s size after the initial conditions have been settled. The only question left is how much magma will pour forth.

5. CRATONS

When I first wrote about cratons last year, I thought that there might still be independent, small cratons that had been uplifted in the early days of the Earth (when the lithosphere was thinner and easier to shear) that could be found in parts of today’s oceans. I listed the Kerguelen Plateau as a candidate.

I now believe that all of the cratons from the early Earth may be already conglomerated into existing continents, or, alternatively, subducted underneath them. This does not rule out the possibility of an independent early-Earth craton turning up on the seafloor somewhere, but I now consider this scenario to be unlikely.

The Kerguelen Plateau dates from 120 – 35 MYA. Zealandia goes back farther into time, but doesn't even reach 500 MYA.

I conclude that most or all freestanding cratons are the result of more recent magmatic events. 17 78, 79, 80, 103 pg 4

6. THE CARIBBEAN LARGE IGNEOUS PROVINCE

After putting together the scenario for South America and then North America, I realized that the Caribbean LIP (Large Igneous Province) could be explained, also. I had originally believed that this explanation was beyond the information that I possessed.

The Caribbean Plate sits between the North American Plate and the South American Plate. The Caribbean Plate is awash with volcanism, which is called the Caribbean LIP.

There is significant controversy surrounding the formation of the Caribbean LIP and its unusual turning movement. One theory says that the region was formed over the Galapagos hotspot and moved to its present location. Another theory says that the Caribbean Plate and its LIP is the result of interaction with North America and South America, although the mechanism is rather fuzzy 103 .

An analysis of the timing involved helps to clarify the situation. While the LIP was formed approximately 139 MYA to 69 MYA 104 , the dominant phase of this activity occurred 94 MYA to 85 MYA 105 .

When we combine this information with the fact that the New England Seamount Chain stopped 82 MYA and the Laramide Orogeny (Rocky Mountain building) began 80 MYA to 70 MYA (see Appendix IV), a mechanism becomes clearer.

The fact that the new Eastern North American Continent was pulling away to the north and the west since irts inception 202 MYA, would have led to an ocean floor spreading at its southern border.

132 MYA, the uplift of the South American Continent would have absorbed some of the older volcanic output in its Amazonas craton LIP (see Appendix III).

Subsequent volcanic output from spreading would accrete to an area north of South America, and, because South America was moving west, this area could be twisted into its own plate, especially when the Eastern North American started to move in a different direction around 80 MYA (see Appendix IV).

Somewhere around 80 MYA, the Eastern North American Plate encountered the tail of the north and westward moving tail end of the Siberian Plate and rotated clockwise, bringing the tail of the Eastern North American Continent somewhat to the south, gradually killing the ocean floor spreading and then twisting (and possibly creating) the Caribbean Plate.

The Chicxulub impact 65 MYA would have augmented this North American move to the South, firmly ending the Caribbean LIP formation. More movement to the south by the Eastern North American Continent would have occurred 35 MYA due to the Chesapeake Bay impact (see Appendix IV), causing more rotational movement by the Caribbean Plate.