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Cause & Effect Involving Cosmic Impacts and
Antipodal Volcanism
Shown below is my response to an
innovative look at antipodal volcanism, as published in Science Magazine on
2October2015. Although this look at antipodal impact effects is far less
ambitious than my proposal, it does have the courage to move in this direction,
even though mainstream geology doesn't want to consider the possibility of
cause and effect in this regard.
Examining Cause and Effect 66 MYA In the Chicxulub
Impact & Deccan Traps
The article entitled "State
shift in Deccan Volcanism at the Cretaceous-Paleogene boundary, possibly
induced by impact," by Paul R. Renne et. al., was published in the 2October2015
issue of Science.
This article presents evidence that the Chicxulub
impact caused a new, different, and much more vigorous kind of volcanism at the
Deccan traps in India 66 MYA. This article also presents the possibility that
the Chicxulub impact may have been the trigger for the massive volcanism at the
Deccan traps.
Previous to this article, the geological community has
been reluctant to seriously consider the possibility of cause and effect
regarding the Chicxulub impact and the Deccan traps volcanism. The reason for
this reluctance has been due to the mantle plume mechanism, as understood
today. The current theory posits that a mantle plume rises through the mantle
at a rate of about one inch per year. This means that a mantle plume rising
from the mantle/core boundary would take approximately 100,000 years to reach
the underside of the Earth's crust. Therefore, it would be impossible for an
impact to create a full, synchronous mantle plume eruption.
However,
Renne et. al. have found evidence of a definite change in volcanism at the
Deccan traps that dates to the same time period as the Chicxulub impact. While
this contemporaneous change in eruption could be viewed as merely a
coincidence, it is also possible that this new volcanism could be the result of
impact energy setting off a mantle plume that was nearly ready to burst forth
anyway.
And what a bursting it was. The Deccan traps produced by far
the largest amount of volcanic material emitted in the last 100 million years.
In fact, the scale of this eruption was one of the largest in the known history
of the Earth.
So, on the one hand, Renne et. al. are saying that we may
now be able to eliminate the uncomfortable coincidence of the biggest (by far)
impact of the last 100 million years happening at the same time as the biggest
effusion of lava (by far). We can now consider these synchronous events to be
the likely result of cause and effect, rather than the result of pure
coincidence.
However, in another sense, we have merely traded one
coincidence for another. We now have the coincidence of a super massive mantle
plume being ready to burst forth at just the right time to coincide with the
super massive Chicxulub impact. How convenient.
Furthermore, there is
no evidence of other examples of extraordinary volcanism at the same time. The
Hawaiian hotspot system was operating at that time and it didn't go crazy.
Neither did any of the other volcanic systems.
Why do we have the
Deccan trap system going completely ballistic and the other volcanic systems
staying relatively quiet? This is almost as bad a coincidence as the previous
lack of cause and effect coincidence.
I would like to suggest an
alternative that will solve this coincidence of the Deccan traps as being the
only volcanic system to go ballistic at the time of the Chicxulub impact. This
solution involves a reexamination of the location of India 66 MYA.
India was a continent on the move 66 MYA. Famously, it was moving at a
rate of 15-18 cm per year, (double or triple the usual tectonic plate rate) as
it raced towards its impact with Eurasia. But the question is: "Where was it
moving from?"
The usual theory has India sitting off the coast of
Africa 66 MYA (while its Pangaean partners, Australia and Antarctica, had been
moving east and a bit south for almost 200 million years). Then, just before 66
MYA, India races to the north and east. This movement allows India to pass over
the Reunion Island hotspot 66 MYA for a big jolt of lava eruption.
Mark
Richards, one of the authors of the 2October2015 Science article, indicates why
India's location was not at the antipode of the Chicxulub impact in a
University of California - Berkeley release by Robert Sanders in April of 2015.
Sanders writes, "He (Mark Richards) stresses that his proposal differs from an
earlier hypothesis that the energy of the impact was focused around the Earth
to a spot directly opposite, or antipodal, to the impact, triggering the
eruption at the Deccan traps. The 'antipodal focusing' theory died, when the
impact crater, called Chicxulub, was found off the Yucatan coast of Mexico,
which is about 5,000 kilometers from the antipode of the Deccan traps."
So, what's wrong with the usual theory? Lots.
First, there is
no doming of the layers of rock around the site of the volcanism, as noted in
the extensive research of Dr. Hetu Sheth and explained in his articles at
www.mantleplumes.org. In all other cases of hotspot volcanism in the world
(except for the hugely massive outpourings of the Siberian traps 252 MYA),
there is doming around the site of the volcanism, as the hotspot melts its way
to the surface over the course of five to twenty million years, depending upon
the thickness of the Earth's crust at that location.
Second, with a a
plume eruption, there is a hotspot trail. The seamounts leading up to the
Hawaiian Islands are a classic example of this characteristic. In the case of
the Deccan traps, there was a huge underlayment of basalt underneath the
western side of the fast moving Indian peninsula. This huge underlayment dated
from 66 MYA at the Deccan traps down to 60 MYA at the tip of the peninsula
… and then it stopped! There is no trail of seamounts leading to the
Reunion Island hotspot.
What kind of hotspot acts like this? It's not
the kind of hotspot that we find anywhere else on the planet.
Third, as
noted before, there are no other volcano systems going ballistic at this time.
Why not?
Fourth, again as noted by Dr. Hetu Sheth, the lava of the
Deccan traps was extruded at 30° south latitude. The usual theory has to
invoke "polar wander" to explain this, since the Reunion Island hotspot is
located at 21° south latitude.
All of these problems can be
resolved by reexamining the purported position of India 66 MYA. If we assume
that India (which was located slightly farther to the north than Australia and
Antarctica in the Pangaean arrangement 252 MYA) moved with Australia and
Antarctica to the west and south, then India would have actually ended up at
the antipode of the Chicxulub impact 66 MYA.
In other words, the
antipodal focusing theory may have been abandoned prematurely.
If we
look at India as laying on its side on top of Australia 66 MYA, the Deccan
traps site could have easily been located at 30° south. Furthermore, the
path of India from that location to its present site today would have brought
it along the edge of the Southeast Asian peninsula. India would have created
the Sunda trench and pushed up much of the land of Java, Sumatra, Thailand and
Malaysia as the coriolis effect forced it to take a curved arc to the north and
east. After crashing into Asia and building up a huge plateau in Asia on its
easterly side (see Gregory D. Hoke et.al.'s article entitled "Stable isotopes
reveal high southeast Tibetan Plateau margin since the Paleogene" in Earth and
Science Letters, April, 2014 about the massive nature of this easterly plateau
40 MYA), the Indian continent would have slid to the north and east to the area
of least resistance, opening up the Bay of Bengal and building up the Himalayan
plateau to the north and west. Note that the coast of Burma fits right into the
coast of eastern India, especially after allowing for the huge amount of
sediment from the Ganges river that filled in some of the gap, creating most of
low-lying Bangladesh.
More importantly, this scenario allows us to
account for a huge, raging hotspot that left a very visible hotspot trail after
the Indian continent had finished passing over it 60 MYA. This huge hotspot is
not just a line of seamounts. Rather, it is the entire Indonesian Island chain,
including the western sides of Java and Sumatra. And where is this giant
hotspot? It is located just to the north and west of Lake Toba in Sumatra,
where it last erupted 74,000 years ago in the biggest volcanic explosion of the
last 19 million years. Yes, this is a serious hotspot … bigger than
Yellowstone. And yes, the Indonesian Island chain is the most volcanically
active area in the world.
Please note that the line of volcanic
activity in Indonesia starts at East Timor in the southeast and gradually moves
to Mount Sinabung in the northeast (just beyond Lake Toba), and then it just
STOPS! The Sunda trench (the supposed subductive mechanism) keeps going to the
north and then bends to the east. But the serious volcanism just plain stops
several miles beyond Lake Toba.
If the Sunda trench (the second deepest
trench in the world) were the controlling mechanism for this supposed
subductive volcanism, then we would expect to see at least a reasonable amount
of serious volcanism after the Lake Toba area … but we don't see any. The
reason for this lack of volcanism is the fact that the hotspot hasn't affected
that area yet.
So far, we have seen how an antipodal location of India
would solve the creation of lava at 30° south and how it would answer the
question about a hotspot trail. Furthermore, we have seen some of the evidence
left behind by this alternative journey of India.
The other problems
associated with the usual theory are the lack of doming at the site of
volcanism and the fact that no other volcanic systems were behaving like the
Deccan traps 66 MYA. The antipodal focusing theory deals with these problems,
as well.
The Earth is nearly spherical in shape. If the Deccan traps
were located at the antipode of the Chicxulub impact 66 MYA, then the huge
radiating earthquake forces would have travelled around the world and focused
at this antipode. This concentration of earthquake waves at this one spot would
have shattered any cohesion of the rocks at this location. This giant
earthquake, estimated to be as much as 12.4 on the Richter scale, would have
created an incredibly weak crustal area at the antipode.
Therefore, if
an incipient mantle plume were located at or near enough to the antipode that
its plume head would extend to the antipode, then it would have an easy avenue
with little resistance through the Earth's crust. This is an advantage that no
other incipient mantle plume on Earth would have. This would mean that the
plume would not have to spend 5 to 20 years doming and melting its way through
the crust. Therefore, there would be no doming needed, since the extremely weak
crust at the antipode would offer little resistance.
Thus, the
questions of doming and contemporaneous eruption of an incipient mantle plume
would be answered by an antipodal location of India.
At this point, we
have found that an antipodal location of India addresses all of the concerns
relating to cause and effect for the Chicxulub impact and the Deccan traps
eruptions … except one.
This unanswered concern would be the
unlikely coincidence that the largest incipient mantle plume of the last 100
million years would just happen to be lurking right at the antipode of the
largest cosmic impact of the last 100 million years. While this type of
coincidence is possible, it isn't necessarily likely.
Is there some
other way to explain this kind of correlated event that doesn't rely upon
unlikely coincidence?
Well, yes, there is. There is the possibility
that the extreme shaking (s waves) created by a very large cosmic impact could
cause the mantle to become much more permeable. In this way, some of the vast
energy of the impact (p waves) could be transmitted around the core to the
opposite side of the planet.
Due to the likelihood of an off-center
impact, it is probable that the center of the energy antipode (p waves) might
not be exactly at the same spot as the physical antipode, but it should be
relatively close. If the plume head is too far away (either because the plume
head is too small or because of a very off-center impact) from the physical
antipode, then this new mantle plume will have to go through the 5 to 20
million year process of melting and doming in order to reach the surface.
However, all of this talk of a much more permeable mantle allowing for
the nearly instantaneous creation of a mantle plume at the energy antipode of a
large impact is quite speculative. After all, wouldn't we then expect other
not-quite-so-large cosmic impacts to show contemporaneous volcanism at or near
their physical antipodes, as well?
Well, guess what? They do!
In the past 100 million years, the Earth has seen four large impacts
from cosmic objects that produced craters of more than 55km in diameter.
Although the Earth is an active planet that erases much of the evidence of
events over time, we can still reconstruct the locations of the Popagai,
Chesapeake Bay and Kara impacts, along with the attendant contemporaneous
(allowing for doming) antipodal volcanism and the subsequent hotspot trails.
If we go back 50 million years more, we find that the two additional
examples which occurred during that time provide similar, but
harder-to-pin-down-exactly results.
This means that, if we include a
position for India that is antipodal to the Chicxulub impact, we are batting
six for six in the category of contemporaneous antipodal volcanism among the
larger-than-55-km-in-diameter impact examples occurring in the last 150 million
years.
Naturally, a reader would want to see more detailed information
about these claims before accepting them. On the one hand, this level of detail
is beyond the scope of this already very long letter. On the other hand, the
detail for these claims is freely available at
www.solvingthemassextinctions.com.
So, do I agree with the paper by
Renne et. al.? Absolutely. Not only does this paper provide us with important
new information about the nature of the change in the Deccan traps eruptions,
but it also allows us to consider new paths to an entirely different
understanding of what may have really occurred there.
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