Hello and welcome to the tenth episode of KaippsCafé!
Today, we'll be talking about Geology.
'Bhoogarbhashasthram' - the Malayalam term for Geology, does not define this branch of science well.
Geology as a branch of study, does not stand alone.
It's a science closely tied to various other scientific disciplines.
Evolution, Astronomy, and Oceanography are all connected to Geology.
I'll be using this area - the Arabian peninsula - as an example, to explain Geology to you.
There is a specific reason for this.
The changes that have occurred in nature, in the last 10-15 million years, are very clearly visible here.
Usually, we can easily stretch our imagination to cover our lifetime.
For example, I'm 50 years old, and I'll easily be able to remember/imagine events of the last 50 years.
But things get tougher when the scale changes.
For example, if you ask me how many days it would take me, to finish 10 oranges...
... I'd say maybe in 4 days... Or lets say 5.
If I have 2 a day.
That number is something I can imagine.
But if you ask me how long it would take me to consume 1 million oranges, I'd not be able to figure it out.
It would even be difficult to imagine this [calculation] with a 1000 oranges.
And this is the fundamental issue.
Our brain is not designed to process large numbers.
It is only equipped to process much smaller things.
This is true for scale in time, as well as scale in space.
Our brain has limitations when it comes to processing and holding information related to space and time.
That's why we are unable to comprehend the period of time involved in evolution.
Or the 4.5 billion year old universe! [errata: age of the universe is 13.8ba, age of the earth is 4.5ba]
We can keep adding a lot of zeroes, but you can't really comprehend the length of that period.
There are people who don't believe in evolution, because their imagination doesn't stretch beyond 10,000 years.
Even that is difficult for them to understand.
We can use expressions like - 'time immemorial...' or refer to 5000 or 10,000 years as mere numbers.
But it's not possible to assimilate or assess these periods.
When we Keralites talk of our history, we refer to the history of 5000 years - from the Neolithic age onward.
The 'new stone age' which existed between 10,000 to 5000 years ago.
The writings -or rather the petroglyphs- you see in the Edakkal caves, belong to this period.
Even that time frame is difficult for us to understand.
And beyond that, we make do with a set of exaggerations, stories and myths.
But history stretches much farther back. And that's what we'll be talking about today.
In the last episode I touched upon the question 'How did deserts originate?'
In this episode, we'll be taking a detailed look at that question.
The super-continent 'Pangaea' formed in the Triassic period, 250 million -or 25 crore- years ago.
Pangaea was a huge landmass which contained South America, Africa, North America, Australia, and India.
Gradually, these [tectonic] plates shifted, and reached their current locations.
An interesting fact is that, when the Indian subcontinent fused with Asia...
...the compression caused by merging of the tectonic plates, caused the Himalayas to rise up.
And the Himalayas continue to rise to this day!
These continental shifts happen at extremely slow speeds.
Again, this is something unfathomable to the human mind, since its natural time scale is about a 100 years.
So how do these continents shift?
Compression between the Arabian peninsula and the Zagros Mountains caused the Hajar mountains to rise.
This compression is ongoing - and might lead to the disappearance of the sea gulf.
Eventually, there is a strong probability that the Arabian peninsula and the Asian continent will merge together.
This process is known as 'subduction'.
During subduction, when two plates press against each other, the older plate slides under the newer one.
Visual proof of this phenomenon can be clearly observed in some spots.
You can actually observe waves -called ophiolite formations- on cliff-sides.
These can be found in northern Oman, Hajar in UAE, Yemen etc.
The plate movement here, is relatively quick.  The plate moves between 2-3 cm per year to the north.
Those of you living in Fujairah -like my friend Naufal- might have experienced some stress and strain...
...caused by the movements of these mountains.
The crust that we see, called the lithosphere, is floating on a relatively viscous -almost rubbery- basalt layer.
And no! It's not rubber. Don't go around telling people that I said it was rubber! :)
What I mean, is that it's a viscous surface - like rubber.
Above that, is the dense crust - the Lithosphere.
These plates are moving. A basic wiki search will give you the details of how many plates exist.
When plates compress against each other, mountains are created.
And when plates separate, ridges are formed.
Some of these ridges -or caverns- located on ocean floors
Volcanic processes, including eruptions and lava flow occur in these ridges.
So, subduction and ridge-formation can be the cause of volcanic activity and earthquakes.
For example, the frequent earthquakes in Iran, are caused by these movements.
If you look at earthquake prone areas on a map, you'll find that these areas are on the edges of tectonic plates.
When we talk about climate change, we usually refer a 100 year period.
But climate change is not a new occurrence.
Since ages... the Malayalam term 'yugam' (meaning age) is complicated - don't ask me how long a 'yugam' is! :)
Basically, every 24,000 years, our planet wobbles on its axis.
Have you noticed the way a spinning top shakes slightly when its about to stop whirling? That is called wobbling.
The same way, our plant wobbles once in 24,000 years.
When it wobbles, it shifts approximately 23 degrees.
This changes the position of the polestar - because the Earth's axial tilting changes.
Apart from this, once every 100,000 years, there is a variation in the orbital ellipse. The Earth's path changes.
And when this happens, there are enormous climate changes.
The planet goes through ice-ages. Desertification occurs.
The weather in pretty much the same in Africa and the Arabian peninsula - with very minor variations...
... like the continuous rains in Oman because of the monsoons.
Both these regions went through desertification during the same period.
So the orbital elliptical change is one of the main reason for the formation of deserts.
Similarly, every 14,000 - 24,000 years, when the wobbling is completed, another set of climate changes happen.
Which means that the earth has gone through multiple ice-ages.
Ice-ages cause mass extinctions and huge losses of life.
On the other hand, when the situations are conducive, there are explosions of life!
For example, during the Triassic period, there was a burst in plant life and marine life.
Huge marine animals evolved.
People have various doubts about evolution. "If humans evolved from monkeys, why are monkeys still around?"
Such silly questions arise when people cannot comprehend such enormous time periods.
And because they do not realise that humans and monkeys evolved from common ancestors.
Not everyone thinks at the same level. We need to help them understand.
This happened over millions of years.
And such doubts arise when people are unable to imagine the time involved.
The extreme climate changes that we were talking about, occur once in 24,000 to 100,000 years.
And along with this, the tectonic plates continue moving.
These movements cause climate changes, create seas...
Twice, seas called the 'Tethys Ocean' formed over the Arabian peninsula and the African continent.
The Sahara was once an ocean!
It was a shallow sea.
This sea was in fact connected to the Mediterranean sea.
This ocean was home to ancient whales.
There is evidence that they used these shallow seas for giving birth to and rearing their young.
There is evidence of fresh water lakes as well - freshwater snail shells have been discovered in Aquifers.
When something like these shells are discovered, how do we figure out how old they are?
That process is called 'carbon dating'.
You've probably heard about it. But what exactly is carbon dating?
Carbon, has multiple isotopes.
Now you'll want to know what isotopes are!
I suggest you go take a quick look at Wikipedia! :)
The three isotopes relevant to our discussion, are Carbon-12, Carbon-13, and Carbon-14.
Carbon-14 forms in the atmosphere due to cosmic radiation from the sun.
This isn't the 'Deepak Chopra' version of cosmic radiation.  This really exists.
Incoming cosmic rays liberate a neutron from Nitrogen-14 and turns it into Carbon 14.
During photosynthesis, plants absorb carbon-14 from the atmosphere.
They entice it in, and make food out of it! :)
Eventually, these plants get eaten by herbivores.
The carbon-14 remains undisturbed in the organism until death. There is 0% decay.
When the organism dies, this carbon-14 begins to decay.
And it is based on this level of decay that we calculate how long the organism has been dead.
For example, if the decay is 50%, we can confidently say that the organism has been dead for 5,730 years.
Or if it is a piece of wood, we can assess its age by carbon dating the organic matter present in it.
If the level of carbon 14 is at 12.4% for example, we can estimate that the piece of wood is 17,200 years old.
These are estimates - but they are calculated estimates.
This is how we date organic matter.
How do we date inorganic matter? Like rocks for example?
We use Uranium–Lead dating.
This can be used for dating meteorites as well as earth origin rocks.
It is accurate up to 4.5 billion years.
Because the half-life of uranium-238 is about 4.5 billion years.
Using this method, when we compare dust from the moon to earth dust, we find that they are the same age.
That is how we establish that the earth and the moon were formed around the same time.
Geology and archaeology are studies based on evidence. The rest are just exaggerations and stories.
And when we learn to accept these stories are mere tales, we will be able to appreciate these fields of study.
Geology and archaeology can be employed to discover new things everyday.
If you look around your house, and pick up just any rock. If you study it closely enough, you can find a fossil.
Because these are all sediments - and they contain fossils of small and micro organisms.
The more calciferous the sediment is, the more organisms were present in it.
That is why sedimentary rocks are so important.
UAE's Hajar region is fully comprised of sedimentary rocks.
Hajar has seen various cycles of subduction and upliftment. But all these were in the last 10 million years.
But the fossils on the mountaintop are 250 million years old!
Which makes it obvious that the mountains rose from the lithosphere when the plates collided.
This is how we understand which species existed in each geographic region.
And this can be used to reestablish tectonic plate movement itself!
Another method [used in Geology], is called coring.
Coring is a technique used commonly in Geophysics.
You drill into the earth using a hollow drill, and examine sections of sediment present in the core.
Each layer can be carbon dated to assess its age.
This becomes a timeline.
Each section of the core, tells a story of a period.
We can spot flooding, mass-extinctions, alluvial flows... and a lot of other things.
That's the beauty of it!
Coring yields different kinds of sedimentary deposits in different areas.
This is how evidence is created.
Stories will not suffice. You need to establish evidence. That's when it becomes a science.
This is the tenth episode.
Please provide your feedback about this episode, as well as about the previous episodes.
Please like and subscribe.
The channel is now available on YouTube and Facebook.
And its success depends on your encouragement.
Thank you for listening!
