Jim's topic for the wedge is:
What geological concept or idea did you hear about that you had no notion of before (and likely surprised you in some way).
This was a hard one for me, because I feel like there is so many things
that could be written about and it's hard to narrow it down to just
one. Finally I came up with this one.
THE ALVAREZ HYPOTHESIS
Here (Wikipedia)
When I was in undergraduate school, the department I was in was very
small. Because it was so small the professors there encouraged us to go
to conferences, intercollegiate field trips and listen to guest
speakers at other nearby universities - where the department had some
arrangements where we could get in, since they couldn't bring the
speaker to our department due to budget constraints.
When I was
very new in the department some of the more senior students had gone to a
conference in Toronto, Canada. They came back and the few of us who
didn't go were very curious about the conference - and were asking a ton
of questions about it. One of my friends was telling us all about it
and that J.Tuzo Wilson was the speaker that got most of the attention
with his theories about plate tectonics. I couldn't believe it when one
of my very old professors (he got his degrees before WWII) in the
department said that J.Tuzo Wilson's (
here) stuff was a '
bunch of bunk',
and his theories would not hold up with the test of time. (At that time
'74, Wilson's theories were mostly known through his articles and he
was mentioned in very few text books.) I was absolutely shocked by this
attitude of that one professor, because what little I had read of
Wilson's theories seemed very believable to me. I felt like this
professor was the one who was wrong. I lost a lot of respect for him
with that one comment, and started to question what he was teaching me
in his classes. This professor had stagnated in his mind set by only
accepting what he was first taught and not expanding his mind to other
ideas that have developed with advent of other technologies.
After that discussion, I told myself I should always keep an open mind
and not limit my thinking like that professor had done with Wilson's
theories.
So a few years later, I went to visit
another university to hear this guy present his research. (I wish I
could recall his name but it has totally faded from my memory and also
the title of his speech.) At first he was pretty charismatic and came
across as being very believable. He had done a lot of research on the
Cretaceous -Tertiary (K-T)(Mesozoic/ Cenozoic) boundary. He theorized
that some catalytic event had occurred, which caused the dinosaurs and
other animals to have a mass extinction. The mass extinctions had been
well documented for quite awhile, but what set his ideas apart was he
was claiming that the extinction was due to a single event and not a
gradual demise of the animals as it was then believed to have happened.
He pointed out how all across the world there was this dust layer with a
radiation marker in it that could be traced which always was associated
with the end of the period. He had traveled to (or gotten) different
places in the world collecting samples and then analyzing that layer.
He concluded that it had all come about from a single event, that caused
the greenhouse effect which lead to the mass extinction.
Up
to this point everything seemed very believable and done scientifically
and thus deserved our consideration. This was something that was
totally new to me and surprised me. I was excited about the
implications of what he was saying.
But then he lost the
audience as he told us his hypothesis as to what the event was that
cause this dust layer. What he then said caused so much commotion in
the auditorium, I had never seen anything like that before or after. All
these educated people then put him through one of the most grueling
times I had ever seen anyone endure to defend his hypothesis.
His hypothesis was that
the dinosaurs had a nuclear war,
and that was why there was this radiation associated with this layer.
He then went on and named Tyrannosaurus Rex as the perpetrators of this
event. He compared the brain size of a human and the T Rexes and
pointed out how much bigger T Rexes were than humans and thus they must
have had more mental capacity than man. He had some other data to back
up his ideas but this is what stuck with me all these years.
The man defended himself well but when he was done most of the people
there dismissed everything he had to say as the old professor put it as
'bunk', because his hypothesis was so hard to accept. Some of the
comments I heard as I was leaving was he had been watching too much Star
Trek or read too many science fiction books or had too much of an
active imagination, etc. What got to me was how they treated
everything
he had to say as wrong and didn't give him the benefit of the doubt for
any of it being true. I must admit I went along with the crowd, and
thought it all crazy stuff too, but I also reminded myself I should keep
an open mind. I didn't even consider that there might be another more
reasonable explanation to muse upon.
I kept on thinking about
this speaker and how he defended him self. One of his very last
comments was 'If man were to have a nuclear war today, how would the
intelligent life 65 million years from now know that man was just as
intelligent and that he was able to develop devices that could destroy
the world. Wouldn't everything he had created be destroyed either by the
war or by the natural processes that were sure to have occurred since
then. What evidence would there be to prove man was intelligent and that
he was capable of causing so much destruction?' I never heard of the
guy again or of his theory and basically let it drop for my mind.
Then around 1982, I saw an article about the Alvarez hypothesis. The
Alvarez's were basically presenting the same type of results from their
data that the first guy had obtained years before. They too concluded
that the K-T boundary was due to a single event only their hypothesis as
to why this dust layer occurred was totally different. The Alvarez's
believed it was due to a meteorite hitting the earth.
In my
mind I compared the two. I could accept the Alvarez's hypothesis, while I
couldn't the other guy. I felt sorry for the first guy. The first guy
had had very legitimate data yet he failed to connect the points
properly. No one took him seriously and
all of his stuff was
dismissed as wrong. As far as I can tell his material was never
published. Instead of getting recognized for the work he did do-- he is
now forgotten. While the Alvarez's presented something that the
geologic community could accept, and they are now recognized for it thus
getting all the credit for it.
The point this guy failed to
realize was the iridium discovered in association with this dust is
associated with asteroids. A point that would have been easily missed
since that connection wasn't widely established at that time. I guess
it surprised me that the 1st guy didn't consider the possibility of a
meteorite impact and present that too. In fact it surprised me that none
of us even brought that up as a possible explanation to ask him if he
had considered that when we were grilling him.
(It did make me
realize that I shouldn't fall in love with just one idea and that I
should pursue as many different ideas as possible when analyzing
things.)
When I read the article by the Alvarez's, I
was working as a geologist with a major oil company in the Gulf coast
region. At the time I was amazed that there were successful wells being
drilled in areas that most of the industry had dismissed as being
unproductive. I felt these operators had some bit of information or
technology that gave them some insight that the rest of us was missing.
I felt like I needed to come up with something along those lines too so
that I could have an advantage over others.
I felt this
article might just might be it for me. It was something I could sink my
teeth into and work with. I wondered just how many people would make
the connection to a single meteorite event causing the the Cretaceous
Tertiary boundary. To most of them the K-T boundary was just a geologic
time thing where there was mass extinctions with no connection to the
gulf coast except in the naming and dating of the formations.
I
realized that iridium layer could be something that could be mapped and
followed around the gulf area. Any place that had this sediment should
then be able to be mapped. I figured it could have a characteristic mark
on the well logs and maybe even with the seismic data. I gathered from
what the Alvarez's wrote, that meteorite would have shaken up the whole
world. In the gulf area, there were already a lot of normal faults
associated with the forming of the basin (going back to J. Tuzo Wilson
ideas, which were then widely accepted and used to interpret the
formation of the gulf.). The impact of the meteorite and the resultant
shaking of the world could have caused some of those normal faults to
shift again. The shaking could also cause the oil and gas to migrate.
Traps may have been formed where there hadn't been traps before. The
possibilities seem so exciting with what I could do with this line of
thought.
I tried to present my idea to my boss so I could work
on it more. I was reminded that I was a developmental geologist and I
should stick to that- the idea was dismissed as bunk. It wasn't even
passed on to the explorations geologists in the company. When I was
done with that meeting I knew what that first guy must have felt like
at the time. I felt like I was onto something then and was frustrated
because I couldn't convince others of its merit. I let the idea drop and
never followed up with it because there was so many other things to
work on at the time. We were mainly trying to figure out why a zone was
as prolific as it was when the electric logs indicated it should not be
productive or barely produce anything at all. Since we couldn't rely on
the standard interpretations we needed also figure out the extent of the
field, which also taught me a very valuable lesson that things don't
always happen to be the way you think it should be.... and to always
keep your mind open to new ideas.
Since then I've
like seeing the work that has been done with the Alvarez hypothesis.
When years later they discovered the Chicxulub crater in the Yucatan
peninsula and I heard about it, I felt my thoughts about this hypothesis
would be even more relevant to the oil and gas industry than I had
previously thought. Unfortunately by then I was out of the industry and
into a totally different line of work so I've never had the chance to
pass it on to anyone until now. I just wonder who else has thought like
me along those lines?
HERE'S SOMETHING TO MUSE UPON
-Even though I prefer Alvarez hypothesis and accept it, I keep on
thinking back to the the first guy and sometimes wonder what if the
first guy is right and the Alvarez hypothesis is wrong. Just a thought.
Below is what Wikipedia has to say about that theory and impact meteor with regards to the K-T boundary.
Impact Event
White line added to mark the transition.
In 1980, a team of researchers consisting of
Nobel prize-winning physicist
Luis Alvarez, his son geologist
Walter Alvarez, and chemists
Frank Asaro and Helen Michel discovered that
sedimentary layers found all over the world at the Cretaceous–Tertiary boundary contain a
concentration of
iridium
many times greater than normal (30 times and 130 times background in
the two sections originally studied). Iridium is extremely rare in the
earth's crust because it is a
siderophile, and therefore most of it travelled with the
iron as it sank into the
earth's core during
planetary differentiation. As iridium remains abundant in most asteroids and comets, the Alvarez team suggested that an
asteroid struck the earth at the time of the K–T boundary.
[72] There were other earlier speculations on the possibility of an
impact event, but this was the first evidence uncovered.
[73]
Such
an impact would have inhibited photosynthesis by generating a dust
cloud, which would block sunlight for a year or less, and by injecting
sulfuric acid aerosols into the
stratosphere,
which would reduce sunlight reaching the Earth's surface by 10–20%. It
would take at least ten years for those aerosols to dissipate, which
would account for the extinction of
plants and
phytoplankton, and of
organisms dependent on them (including
predatory animals as well as
herbivores). Small creatures whose food chains were based on
detritus would have a reasonable chance of survival.
[58][69] The consequences of reentry of ejecta into Earth's atmosphere would include a brief (hours long) but intense pulse of
infrared radiation, killing exposed organisms.
[37] Global
firestorms may have resulted from the heat pulse and the fall back to Earth of incendiary fragments from the blast. High O
2 levels during the late Cretaceous would have supported intense combustion. The level of atmospheric O
2 plummeted in the early Tertiary Period. If widespread fires occurred, they would have increased the CO
2 content of the atmosphere and caused a temporary
greenhouse effect
once the dust cloud settled, and this would have exterminated the most
vulnerable organisms that survived the period immediately after the
impact.
[74]
The impact may also have produced
acid rain,
depending on what type of rock the asteroid struck. However, recent
research suggests this effect was relatively minor, lasting for
approximately 12 years.
[69] The acidity was
neutralized by the environment, and the survival of animals vulnerable to acid rain effects (such as
frogs)
indicate this was not a major contributor to extinction. Impact
theories can only explain very rapid extinctions, since the dust clouds
and possible sulfuric aerosols would wash out of the atmosphere in a
fairly short time—possibly under ten years.
[75]
Subsequent research identified the Chicxulub Crater buried under
Chicxulub on the coast of
Yucatán,
Mexico as the impact crater which matched the Alvarez hypothesis
dating. Identified in 1990 based on the work of Glen Penfield done in
1978, this crater is oval, with an average diameter of about
180 kilometers (112 mi), about the size calculated by the Alvarez team.
[76]
The shape and location of the crater indicate further causes of
devastation in addition to the dust cloud. The asteroid landed in the
ocean and would have caused
megatsunamis,
for which evidence has been found in several locations in the
Caribbean and eastern United States—marine sand in locations which were
then inland, and vegetation debris and terrestrial rocks in marine
sediments dated to the time of the impact. The asteroid landed in a bed
of
gypsum (calcium sulfate), which would have produced a vast sulfur dioxide
aerosol.
This would have further reduced the sunlight reaching the Earth's
surface and then precipitated as acid rain, killing vegetation, plankton
and organisms which build shells from calcium carbonate (
coccolithophores and
molluscs).
In February 2008, a team of researchers used seismic images of the
crater to determine that the impactor landed in deeper water than was
previously assumed. They argued that this would have resulted in
increased sulfate aerosols in the atmosphere, which could have made the
impact deadlier by altering climate and by generating acid rain.
[77]
Most
paleontologists now agree that an asteroid did hit the Earth about
65 Ma ago, but there is an ongoing dispute whether the impact was the
sole cause of the extinctions.
[23][78] There is evidence that there was an interval of about 300
ka from the impact to the mass extinction.
[79] In 1997, paleontologist
Sankar Chatterjee drew attention to the proposed and much larger 600 km (373 mi)
Shiva crater and the possibility of a multiple-impact scenario.
