Several issues related to Ben's
Antipodal Impact Theory require additional explanation. This chapter will
explore those issues (except for some issues, which are better explained while
illustrating the uplifting of the Indian continent at and near the antipode of
the Chicxulub impact 65 MYA. These issues will be dealt with in Chapter 8.).
IMPACT IN WATER VERSUS IMPACT ON
AS WELL AS ARGUING THE NUMBER OF LARGE IMPACTS
While the issue of impacts in deep
water (50% to 60% of the Earth's surface) versus impacts on-or-near-land has
been addressed briefly in previous chapters, the issue needs further
clarification for two reasons:
1. To establish the validity
of this argument, especially in the light of counter-assertion.
2. To explain the number of large impacts
that have had a truly devastating effect, as opposed to just the total number
of large impacts (impacts in deep water would have a much smaller effect).
There are two specific arguments to
rebut. These arguments are:
1. ARGUMENT #1Impacts on land are
LESS likely to cause antipodal damage than impacts in deep water. A paper by
Jonathan T. Hagstrum in 2004 argues that large-body impacts could cause
antipodal hotspots, as well as hotspots at the original impact site (hotspot
pairs). Hagstrum's paper argues that there is a 99% confidence level that
antipodal hotspot pairs are not due to chance. Furthermore, the paper states:
"Because continental impacts
are expected to have lower seismic efficiencies, continents possibly acted as
shields to the formation of antipodal hotspot pairs."6 pg 1
2. ARGUMENT #2There are too few
extinctions to attribute them the effects of cosmic impacts. A paper by
Rosalind V. White in 2002 notes that:
"Statistical examination of
craters on the Earth and Moon demonstrates that Earth should receive a crater
as big as Chicxulub (180 km in diameter) on average every ca. 31 Myr (Hughes
1998)."2 pg 2979
Therefore, if big impacts produce big
extinctions, why have we only seen six major extinctions in the past 510 years,
when we should have seen approximately 16?
The answers to these arguments are
related, so I will address them both at once. I believe that the answers to
these riddles lie in the fact that more than 70% of the surface of the Earth is
covered with water (with 50% to 60% of the Earth's
surface covered with deep water) .
I believe that when a cosmic object
hits the water instead of the land, the water would absorb a significant amount
of the shock. Therefore, many of the impacts would not have transmitted as much
energy to the mantle, nor would they have caused as much energy transfer damage
at the antipodal area of the earth.
Certainly a large cosmic strike in the
ocean would produce some kind of crater and it would produce a prodigious
mega-tsunami, but mega-tsunamis still only cause regional damage. They don't
usually lead to extinction. It takes massive and persistent volcanism with its
attendant decades and centuries of volcanic winter to lead to massive
extinction. An interesting recent comparative example for the difference (on a
much smaller scale) between water (a loose substance) and rock (a hard
substance) is the story of the British army on the beaches of Dunkirk in France
At that time, Hitler's army had
surrounded the British army and was ready to drive them into the sea
with the possible loss of almost all of Britain's trained troops. However,
Adolf Hitler (prodded by his air marshal, Herman Goering) ordered his Panzer
tank divisions to stand down, while the German air force bombed the British
troops to pieces.
Unfortunately for Hitler, the loose
sand absorbed much of the blast effect from the bombs. Although many of the
British troops were covered with sand, relatively few were injured. The great
majority of the British troops were able to escape back to England on a
jury-rigged flotilla of ersatz troop ships.
Although Jonathan Hagstrum might
believe that impact in water would be more likely to form a hotspot at the
antipode, I respectfully disagree.
Water has an amazing ability to reduce
the impact effect of an object. Water will direct much of the force in all
directions (especially into directions of least resistance), reducing the
impact effect at the specific impact point. For smaller impacts, a cosmic
collision object wouldn't even shock the ocean floor if it hit the Earth in
Perhaps the dissipating effect of water
can best be understood by reading the following report from
report relays the results of U.S. military testing of bullets fired directly
into water in order to see if downed airmen could escape the effects of enemy
aircraft strafing at sea by diving under water. The report focuses on .30
caliber armor piercing rounds (assault rifle equivalents) and. 50 caliber armor
piercing rounds (truly brutal high powered bullets used primarily in
devastating mounted machine guns and high-powered sniper rifles).
"The Bureau of Ordnance
conducted a series of tests to determine depths of water required to give
protection against .50 caliber and .30 caliber AP bullets fired from a few
inches above the water. A target of 1-inch pine boards was suspended at various
depths with their surface at right angles to the line of fire. The Complete
penetration of a board was considered a lethal impact.
"When the .50
caliber bullet was fired vertically downward, the critical distance for
complete penetration was found to lie between 4 ft. and 5 ft. Firing at oblique
angles of 45 to 60 degrees from the vertical reduced the lethal bullet travel
by approximately 1 ft. When the .30 caliber bullet was fired vertically
downward, complete penetration was observed at 1 ft. but not at 2 ft. Based on
these observations a person must be submerged at least 5 ft. to feel reasonably
safe from .50 caliber machine gun fire and at least 2 ft. for .30 caliber
machine gun fire." 7
Earlier in the report, it noted that
soft-nose bullets (the bullets tested in the report above were full-jacketed
military bullets) do not penetrate as well. Soft nose bullets also expand (and
slow down some) and break up.
Many or most of the large Earth impact
objects would be more similar to soft nose bullets than full-jacketed military
Water has strong stopping power, even
from full-jacketed military bullets that are aerodynamically shaped. Two feet
of water can provide reasonable protection from an assault rifle! And water is
especially effective in slowing down soft nose (like most impact objects)
bullets coming in at an angle (like most cosmic impacts).
While most large cosmic impact objects
hitting in deep water would still have a big effect on the planet Earth, I
don't believe that they would be able to transfer enough energy to the antipode
of the impact to cause a major extinction event.
I believe that 50% to 60% of the large
cosmic impacts on Earth in the last 510 million years probably hit water that
was deep enough to effectively stop a major extinction event. Therefore,
instead of approximately 16 major extinction events, we would expect six to
eight major extinction events from the Cambrian to the present day.
Standard earth science texts
1. Cambrian 510 MYA
2. Ordovician 440 MYA
Devonian 365 MYA
4. Permian 250 MYA
5. Triassic 202 MYA
6. End-Cretaceous 65 MYA
OTHER ANTIPODAL THEORIES
This book is not the first to name
geological activity at the antipode of an impact as a possible effect from a
large cosmic object. Several scientists have noted the convergence of
earthquake forces at the antipode and have suggested that this could cause
However, none of those scientists have
been able to link antipodal impact activity to a major impact event in a
convincing manner (I hope to end that drought).
Nevertheless, there are two groups of
scientists who have brought a special insight into the subject. Back in 2003,
Dr. Michael Martin-Smith proposed the "Bullet Theory." This theory posited
major volcanic activity at the antipode of the Chicxulub impact, as a result of
the shock effect transmitted through the lithosphere and the mantle.
As an intriguing sidelight, Dr.
Martin-Smith (a medical doctor who is a life-long amateur astronomer) noted
that on the planet Mercury, there is a large region of jumbled hills at the
exact antipode of the huge Caloris impact basin (1385 km in diameter). Dr.
Martin-Smith also points out the fact that Mercury has not had any volcanism
for at least three billion years
the region of hills (the size of France
and Germany) is "ascribed to a concentration of shock waves emanating from the
Caloris Basin impact."8 pg 4
I had to wonder: If a planet like
Mercury (with no liquid core for effective hydraulic energy transfer to a thin
shell) could uplift a portion of its crust at the antipode (albeit from a huge,
huge impact), then what could be uplifted on planet Earth, with its much more
inviting composition of a small, hard outer shell and a liquid mantle?
The concept of using impact pressure to
change the shapes of objects is not new. It has long been used in metal
fabrication, going back to blacksmiths and even before that.
In particular, the screws, nuts, bolts
and nails that are commonly sold in hardware stores are formed by impact
pressure (mostly during the creation of the heads, but in the case of nuts,
during the shaping of the blank).
More apropos to the question at hand,
the fastener industry also uses special machines called "impact headers" to
extrude metal at the antipode of the impact by the hardened punch. And, in
these cases, the heading machines are moving solid steel, not just a thin
(relative to the size of the impacting force) layer of rock.
A major problem with the position taken
by Dr. Martin-Smith was his assertion that the Deccan traps were located at the
antipode of the Chicxulub impact within one degree. He made this assertion with
no acknowledgment that virtually all models and standard accepted theory showed
the Deccan traps as being located approximately 4000 miles away from the
Dr. Martin-Smith submitted his idea to
Scientific American, but they declined publication.
Looking back on his work, I can see
that he had some of the important factors identified, but lacked a model that
dealt with the Standard Theory's dispute of the location of India.
David C. Weber, Tim S. Bennett and
Charles E. Weber have done useful work in the area of antipodal impacts, both
on Earth and on other planets.
This trio wrote a paper entitled "A
Theory for the origin of volcanoes on Mars" in December of 2008. This paper
hypothesized the proposition that:
the plateaus and
volcanoes of Mars were generated by the focusing of seismic waves from asteroid
impacts on the exact opposite side (antipode) of the planet. These impacts
resulted in mechanical waves that traveled concentrically outward from the
impact and converged and converged on the exact opposite side of Mars, which
then caused major uplift and eruption of magma on a large scale."12
They find that the fact that the two
biggest craters on Mars are antipodal to two large bulges on the surface is too
much to be just a chance occurrence.
This paper adds to the evidence for
uplift on other planets as cited by Dr. Martin-Smith.
Going further, Charles Weber posted a
paper entitled "Lava Flows and Traps from Antipode Disruption by Meteorite
The paper notes that the "association
of lava flows opposite meteorite impacts would require an extremely improbable
coincidence." This paper also states that there is much confusion regarding
trenches and plate tectonic movement.13 Also noted in the paper is
the fact that antipodal impact effects have been bruited about since
"It has been proposed by
David Weber that concentration of seismic waves from a meteorite impact at the
antipode (opposite side of a sphere) on the Earth could be the cause of many of
the massive lava floods of the past. Schultz and Gault proposed antipodal
disruption on the moon by impacts as early as 1975. Hughes, et. al, believe the
affects are more violent in a liquid planet (Hughes). Antipodal disruption was
proposed as possible by Watts, et. al. in 1991 (Watts) and Boslough, et. al.,
wrote of simulations of that process in 1995 (Boslough). The strong correlation
of the bulges and associated volcanoes on Mars and Mercury with large impact
craters on the opposite side makes this hypothesis very credible."13
A very recent (3/28/10) paper by David
Charles Weber is entitled "Meteors, focused quakes, core plumes,
super-volcanoes and extinction 65 Ma."
This paper makes the case that the
antipode of the Chicxulub impact was just off the northern coast of Australia,
near its eastern edge. As the Australian continent moved north, it moved over
the antipodal hotspot of the Chicxulub impact. This hotspot then created the
string of volcanoes and lava fields that run down Australia's eastern side.
The reasoning given for the location of
the antipode of the Chicxulub impact is startlingly similar to my own. We even
come up with reasonably similar antipode positions (mine 30ºS, 132ºW:
his 37ºS, 143ºW).
However, there is a significant
difference in the mechanisms that we used to determine the movement of the
North American plate so that the Chicxulub impact ends up in the right place
(besides the much bigger factor that my antipodal hotspot creates the Deccan
traps and the Indonesian Islands, while his antipodal hotspot stands still and
has eastern Australia pass over it.).
Weber says that there has been a
slowdown of the North American plate as illustrated by the volcanic calderas of
the Yellowstone hotspot as the North American plate passes over it. The older
distances between the Yellowstone calderas showed a much faster moving (in a
westerly direction) North American plate.
Weber's position assumes that hotspots
are stationary and plates just move over them. I don't assume this. My
assumption is that both plates and hotspots move and, furthermore, hotspots can
move more slowly as they grow long in the tooth.
Therefore, in my opinion, the
Yellowstone hotspot may not be telling us much. However, I do believe that the
impact at Chicxulub, itself, helped to move the North American plate
(especially the area around the impact) to the south and west more quickly. I
also believe that this initial thrust would have run out of steam over
time. Appendix IV provides some new insights into the
effects of the Chicxulub impact site, itself.
Weber and I also have some disagreement
about the nature of the forces that cause the hotspots. I see the forces as a
two-step process. The first step involves the focusing of earthquake waves at
the antipode of the impact. This focusing effect pulverizes the lithosphere in
that area and eliminates any need for upwelling lava to spend any energy
shearing the rock. The rock has already been sheared and crushed.
The second step involves a strong pulse
of hydraulic pressure on the liquid material in the mantle. Like any liquid
hydraulic system, the mantle then transfers this pressure (in a rotational
manner around the core) until it finds relief.
If the impact is big, but not too big,
the pressure will find relief in creating a plume that spews forth lava from
the greatly weakened antipodal rock. If the impact is really big, the pressure
can find relief only by additionally uplifting a continent, as well as spewing
forth lava at the antipode.
Weber sees the force as waves. These
waves transfer pressure and focus it at the antipode. As he states in his
"The volcanoes occurred at the
antipode of the Yucatan impact by the focusing of mega earthquake waves, which
both cracked the crust and created a core plume 14 pg 1
The difference between a hydraulic
pulse and a focused wave is especially important when it comes to the idea of
uplifting continents. A hydraulic pulse provides a clear mechanism for
uplifting a continent. A focused wave would just make a bigger hotspot.
UNDERSTANDING THE UPLIFT SHEAR
One of the simpler ways to visualize
this continental uplift phenomenon is to see the area near the antipode as
having millions of little forklift trucks (the pressure energy) beneath it.
Each forklift is exerting its own maximum force (the forklift trucks vary in
size) to lift up the lithosphere.
Right at the edge of the uplift, the
little forklifts have barely enough energy to shear the rock and uplift the
land. On the other side of the edge the little forklifts are too weak to do
Therefore, the rock shears, right at
this point. And, as a special bonus for the little forklifts near the edge, the
power of their near companions on the other side of the shear flows over to
help with the uplift
because these are liquid forklifts and they can
transfer their energy easily.
Despite the differences between Weber's
conclusions and my conclusions, I do find Weber's claims to be plausible. He
does present some interesting evidence in the chain of Australian volcanoes and
lava fields, as well as the huge lava field in the West Victoria Plains.
His antipode site is plausible, as
well. Unfortunately, he must attribute the lack of further evidence to the idea
that the evidence was already subducted (again, plausible) as the Australian
plate moved north.
Therefore, although I believe that my
version of events is significantly more explanatory and much more robust, I
cannot absolutely rule out Weber's claims. In fact, if I had run across his
paper in my early research, I might have been convinced that Weber's answer was
entirely satisfactory and that I didn't need to explore further.
However, now that I know about Weber's
work, I can suggest an alternative answer to the facts that he presents.
The volcanic activity on the eastern
side of Australia appears to be intermittent and scattered for the time period
of 71 MYA to 35 MYA. During this time period, there were actually more
volcanoes erupting in the south than in the north15 (Weber posits a
steady progression of a hotspot from north to south).
After 35 MYA, the history shows a
steady north to south progression of volcanoes, starting in Queensland and
working on down through New South Wales to Victoria over the years.
An Oregon State University posting on
"Volcanoes in Australia" states:
"Australia is far from the
edges of the Indian-Australian plate, yet volcanoes have been erupting along
the east part of the continent for the last 33 million years." 16 pg
The posting goes on to say:
"The volcanoes of Australia
define several chains with progressively younger volcanoes to the south
These age progressions suggest that a hotspot feeds magma to the volcanoes.
Unlike the Hawaiian, Society Islands and Yellowstone hotspots, which produce a
single chain of volcanoes, the hotspot beneath eastern Australia is broad and
may take advantage of weak places in the plate to feed magma to the
surface."16 pg 2
And yet, there is a significant lava
field far up north that dates to around 60 MYA, as noted by David Weber.
I would suggest an alternative solution
to this set of facts.
I would attribute the 60 million year
old lava field (which would have been located within a few hundred miles of the
Indian antipodal hotspot, as I calculated its location), to the hydraulic
pressure of the Chicxulub impact finding weak spots near the antipode, starting
65 MYA. This area may have erupted for five to seven years before the initial
surge of the hotspot area moved too far away to continue supporting it.
I would suggest that the volcanic
hotspot activity in eastern Australia that began around 35 MYA to 33 MYA was an
entirely separate event. As Weber suggested, this was probably the result of
volcanic activity at an antipode. However, I believe that this volcanic
activity was the volcanic activity at the antipode of the Chesapeake Bay
impact, which occurred 35.5 MYA and produced a crater of 90 km in diameter (as
opposed to the 170 km in diameter crater at Chicxulub).17
The antipode of the Chesapeake Bay
impact (located in the Baltimore and Washington, DC area in the USA, now at
37ºN, 76ºW) would have been near this location 35.5 MYA. The
Chesapeake Bay impact would have been a big enough impact on-or-near-land to
create a big hotspot at its antipode, but not necessarily big enough to uplift
even a small continent.
Because the antipode of the impact was
under Australia's Great Dividing Range, the weight of the rock could have kept
most of the lava from bursting out onto the surface, until the lava finally
reached a non-mountainous area in the West Victoria Plains, where it gushed
MICHAEL RAMPINO & GEORGE WILL
Other well-known figures have looked at
impacts, extinctions and antipodes, too.
Michael Rampino of New York University
has cited volcanism as a big player in major extinctions. However, he has
concerns about whether the volcanism is truly connected to the impacts.
Specifically, he is concerned that some of the volcanism at the Deccan traps
predates the Chicxulub impact event.34
It is true that there has been some
basalt lava found to the north of the Deccan traps dating to 72 MYA and some
near the Deccan traps dated to 68 MYA. Nevertheless, the vast outpouring that
makes up the Deccan traps dates to 65 MYA, the same time as the Chicxulub
Even noted columnist George Will has
written about the controversies surrounding the impacts and extinctions in a
column on 12/31/09. He focuses on a possible 300 mile wide crater called Shiva
that is located off western India and could have accounted for the sudden surge
of the Indian plate movement to 15 to 20 centimeters per year. However, there
are questions as to whether Shiva is even a crater and, if it is, is it 65
million years old?
Although I have developed a completely
different scenario for India's rapid movement and its starting location, George
Will's comments about India's sudden increase in speed led me to look at the
possibility of India being located at the antipode in a different way
way that involved directional energy.35
UNDERSTANDING THE DIRECTIONAL
When looking at a really big cosmic
impact that comes in at an angle (usually 30 degrees to 45 degrees from
vertical), there are three main factors to consider as far as directional
energy is concerned. These factors are:
1. The Impact Power of the
Collision - As noted earlier, the actual size and speed of the collision can be
moderated significantly if the cosmic object hits in deep water. The truly
important questions are: How much impact power was delivered to the lithosphere
and transferred to the mantle? Was it enough to cause a hotspot? Was it enough
to cause continental uplift? If the impact power was enough for continental
uplift, how big was the continent that was formed?
2. The Angle of Collision - The closer the angle of impact is to
vertical, the more the amount of uplift pressure is delivered to the antipodal
area. With a more angled impact, the pressure is focused, to a greater extent,
slightly beyond the antipodal area, thus creating a smaller "blob" than
expected, but a bigger "tail" than expected.
There is also the cross-sectional angle of impact, which indicates how close to
dead center (full cross-section) the impact was. An off-center hit will result
in the hotspot being located near the edge of the uplifted continent (see
Appendix VII for details). The direction of movement of the continent and the
magma underneath it will be influenced in the direction away from the
A perfectly vertical impact
would produce a perfectly circular continental uplift that would have no
directional energy. A long-tailed continental result (i.e. South America) would
indicate a more angled impact (maybe 45 degrees from vertical). A
shorter-tailed continental result, like the Indian continent, would indicate a
closer to vertical (maybe 30 degrees from vertical) impact.
3. The Rotational Nature of the Impact -
During a cosmic impact, the total amount of hydraulic pressure on the
lithosphere from the mantle determines if continental uplift will take place.
More specifically, the amount of pressure under the uplifted area must be
greater than the shear strength of the perimeter of the uplift and the weight
of the material in the uplifted area.
However, the direction of movement of the uplifted area is
determined by the direction of the magma in the mantle that is located beneath
it. This direction is determined by the off-center nature
of the impact.
For instance, with the
Chicxulub impact, the hydraulic pressure of the impact pulse uplifted the
Indian continent. The nature and power of the hydraulic pulse created a large
"blob" just past the antipode, with a fat, stubby tail (pointing back towards
the Chicxulub impact site).
From the look of
the blob and the tail, it would appear that the new continent would move in a
southwest direction. However, this was not the case.
Since the blob had moved beyond the antipode, the rotational
direction of the magma underneath was now moving back up to the northwest.
Therefore, the new continent was pushed forward in a northwest direction.
No. Upon further consideration, the main player
here was the off-center pressure to the north and
PLACING INDIA AND THE DECCAN
TRAPS AT THE ANTIPODE
No one has seriously investigated the
antipode of the Chicxulub impact as the main source of the volcanism that
caused the End-Cretaceous extinction.
The reason that scientists have not
looked at the Chicxulub antipode is due to the fact that the volcanism occurred
in the Deccan traps of India and scientists have believed that India was not
located at the Chicxulub antipode at that time. In fact, they have believed
that India was located at least 4000 miles away from the antipode (near Africa)
at the time of the volcanic eruptions of the Deccan traps.
Chapter 8 of this book will detail what
I believe is a likely scenario of the uplift of the Indian continent and the
huge eruptions at the Deccan traps. This scenario places the Deccan traps at
approximately 30ºSouth and 132ºWest 65 MYA (see illustration 8-A).
In order for the Deccan traps to be
located at the antipode of the Chicxulub impact 65 MYA, the impact would have
had to occur at 30ºNorth and 48ºWest.
We know that the current site of the
Chicxulub crater is at 21ºNorth and 89.5ºWest. Is it reasonable to
assume that the Chicxulub impact site could have moved 9º South and
41.5º West in 65 million years?
According to various sources on the
internet, the North American plate is moving west at anywhere between 0.4" to
2.4" per year, with the notation that the movement varies from place to place
and there is apparently some turning motion involved.
If we arbitrarily assign a western
movement of 2.3" per year, the math works out as follows:
2.3 inches per year X
= 2360 miles of movement
12 inches/foot X 5280 feet/mile
At a latitude of between 21º and
30º, the average circumference of the surface of the Earth is less than
20,000 miles (it is 25,000 miles at the equator). Therefore, 1º of
longitude at those latitudes is somewhat less than 56 miles. The math is as
20,000 miles/360º = 56
miles per degree of longitude.
Therefore, if 1º of longitude is
somewhat less than 56 miles of latitude, then the amount of latitude covered by
2360 miles of movement would be at least 42º. The math is as follows:
2,360 miles/56 miles per degree of longitude = 42º of longitude.
Since we needed to come up with
41.5º of longitude, we can see that the westerly movement is clearly
within the realm of possibility, although admittedly at the high end of those
movement projections (2.4" being the highest).
However, the factor that will help
explain the southward movement of the Chicxulub crater will also help to bring
the western movement more into the mainstream projections, as well.
Throughout this book, the focus has
been on the events happening at the antipode of the impact site. Now, we are
finally going to see some of the effects from the impact, itself.
The shape of the Indian continent and
the subsequent movement of the Indian continent indicate that the Chicxulub
impact occurred out of the northeast at an angle of approximately 30 degrees to
vertical. So, what would happen at the impact site, itself
At the impact site, itself, the huge
force of the impact would have had an effect on the movement of the North
American plate. Since the object came out of the northeast, it would have
pushed the North American plate, and especially the area around the impact
site, to the southwest.
This impetus would have been enough to
move the impact site from 30ºNorth to 21ºNorth in 65 million years.
This impetus would also have helped the site move west.
As a result, we can see that placing
the Deccan traps at the antipode of the Chicxulub impact site is well within
information concerning the Chicxulub site for several months, I found
compelling evidence that the Chicxulub impact actually occurred near the edge
of the original Eastern North American Continent and pushed most of the tail to
the south and west, creating today's Mexico and Central America. This scenario
makes the move to the south and west even easier to justify (see Appendix IV
for an exhaustive explanation).
The Standard Theory places India off
the coast of Africa 65 million years ago. Because scientists have accepted this
Standard theory scenario without serious question, the idea that the Deccan
traps could be at the antipode of the Chicxulub impact has not been given
In chapter 8, I will present a
different scenario that is backed up by far more evidence than the Standard
Theory could ever hope for. It is time to review the facts and place India at
the antipode, where it should have been all along.
THE NATURE OF THE VOLCANISM
The basic nature of the volcanism at
the Deccan traps is what is called flood basalt lava. Flood basalt lava is not
considered to be explosive. It is not usually associated with high levels of
toxic fumes or clouds of ash.
The volcanoes in the Hawaiian Islands
were created by a hotspot. The usual volcanic lava that comes out of the
Hawaiian Islands is flood basalt lava. It is pretty tame lava.
One of the objections to the idea that
volcanism at the Deccan traps was the prime cause of the End-Cretaceous
extinction is based upon the fact that the lava at the Deccan traps is flood
basalt lava. How could this wimpy, tame lava be responsible for a major
There are several factors to consider
in analyzing this seeming paradox. But first, let's remember the vast nature of
this huge lava field.
The volume of basalt lava at the Deccan
traps originally covered as much as 600,000 square miles (that's a rectangle
600 miles long and 1,000 miles wide) and contained 12,275 cubic miles of lava.
The eruption at Mount St. Helens produced less than half a cubic mile of
Therefore, the factors to consider are:
1. The Magnitude of the
Eruptions - There was 25,000 times more lava produced by the Deccan traps than
by Mount St. Helens. That's more than four orders of magnitude difference. This
was a truly mega-event.
2. The Power of the
Eruptions - The initial eruptions had so much energy behind them that they
could not have been the sedate, smoothly flowing streams of flow basalt lava
that are seen in Hawaii. Even normally tame flow basalt lava would have been
spewed thousands of feet into the atmosphere.
3. Water - The proximity to the ocean and the severely cracked
rock near the antipode could have let water seep into the lower reaches of the
upwelling. Once water, which can violently transform to steam, is introduced,
eruptions can become truly spectacular.
The combination of these three factors
provide plenty of reasons for suspecting that the lava flows at the Deccan
traps spread massive amounts of gas, ash and rock into the atmosphere
and it continued in a furious manner for 100,000 years, with still strong
eruptions continuing for as long as one million years.
This concludes the chapter on further
theoretical explanation. There are other theoretical items that still need to
be addressed, but they are best illustrated in chapter 8, all about the rise of