Why I love Geology II

There are two huge scales in geology, one is Distance and the other is Time

When I was following a geology course with the Open University, one of the course modules was called “Quarks to Quasars” which discussed the scale of distance.

Distance

The purpose of this was to demonstrate the size and distances that science covers.

Quarks are the fundaments constituents of matter and are smaller then 10-19 m in size, while quasars represent the most distant astronomical objects it is possible to observe and are up to 1026 m away. So the obvious question is, ‘How much bigger is the distance to a quasar than the size of a quark?

This needs a little maths – only a little:

Divide the distance away of a quasar by the size of a quark

1026 +19  =  10 45

So the distance to a quasar is 45 orders of magnitude greater than the size of a quark.

These two length scales – separated by a factor of a billion, billion, billion, billion, billion. represent the extremes of human comprehension of the Universe so quarks and quasars therefore serve as convenient limits between which we might attempt to understand the Universe as a whole. 

So if we start with…

A quark which is a billion times smaller than an atom

An atom is a billion times smaller than an apple

An apple is a billion times smaller than Jupiter

Jupiter is a billion times smaller than the distance to the nearest stars

The nearest stars are a billion times nearer than quasars.

These extremes of length of scale are what geologists play with. Talk about,”The world is your lobster” !

Time

The other scale is time. The first question is: “How old is the Earth?”

There are two wildly divergent answers.

One is ‘calculated’ from material in the Bible that says the Earth is about 6,000 years old and the other, from science is that the Earth is about 4.54 billion years old.

I suppose you could choose either but, as a geologist, I can see just by looking at rocks and thinking about the processes that made them that the Earth cannot possible be as young as 6,000 years. Believing that is equivalent to believing that man and dinosaurs used to live on the Earth together until ‘recently’.

The age of the Earth is 4.54 x 109. or 4.54 billion years  +/- 500 million

There are many strange names for the different divisions in geological or “deep” time. It is hard to remember these so I wrote a mnemonic poem a while ago”

Earth Song

Precambrian

I was in hell boing bombed in the Hadean.
I was just alive in the Archean.
I was long present in the Proterozoic

Paleozoic

I was changed b y life in the Cambrian
I brought order to the Ordovician and
I just survived the Silurian.
I nearly drowned in the Devonian, all those fish!
I made coal in the Carboniferous, delta, changes.
I was probably in the Permian desert dust storms

Mesozoic

I was a playa in the triple, arid Triassic,
I evolved with many ‘ites in the Jurassic,
I chalked the Cretaceous, fashioning forams and flints.

Cenozoic

I nearly perished in the Paleogene
I number all in the Neogene
I quaked in the sometimes chilly Quaternary.

I have lived so long, it may seem perverse, but
I want to live to the end of the universe.

I am the worse for wear and war weary,
I am your home, your Earth, cherish me dearly.

The history of the Earth is written in the  rocks for all who wish to read it.

We find no vestige of a beginning,—no prospect of an end.” James Hutton 1726 – 1797

So geologists are free to play in a huge Universe and within an enormous timescale.

One problem apart from an overwhelming feeling of awe for the natural world is that the more you find out, the more you realise that your existence within all these wonders is incidental and you are insignificant and irrelevant to everything that is going on.

Take the white cliffs of Dover as an example. They are made of the coccolith calcite plates that are formed by coccolithophores, which are aquatic, single-celled algae. They are marine and live as phytoplankton in the photic zone of the open ocean, where they are a major source of food and a significant producer of oxygen. They are very small, about 2-5 micron in diameter. These plates form the majority of the chalk.

Now some more simple maths. 

The chalk cliffs of Dover are some 80M high

The chalk was laid down during the Cretaceous period which lasted 80 million years.

So a simple calculation shows that, on average it took one thousand years to deposit 1 mm of chalk.

So, if you lived in the Cretaceous, you wouldn’t even notice that chalk was being deposited. It goes to show one of the principles of geology – most processes happen very slowly and so require a great deal of time – luckily, there is plenty.

So we now have some idea of the distance and time we are dealing with, even if we cannot directly relate to them.

One of the problems with geology and dealing with these scales is that it makes you realise how insignificant humans are.

Here are some facts that might bring this home to you.

Humans have existed on Earth for a short time- about 200,000 years

Dinosaurs existed on Earth for a little longer time – about 135 million years

Maths again!

This means that dinosaurs lived on the Earth some 270 times as long as modern humans have.

Do you think humans will be around 135 million years in the future? No, me neither!

So, in spite of “dinosaur” being used as an insult for an out of date person, they did quite well and have been one of the most successful species on Earth.

Another problem when you are dealing with geology is that you can become a little blasé about these scales. In there area where I live there are several limestone ridges that were deposited in the Carboniferous ( 359 – 297  million years ). It is simple to find fossils in these rocks so when you break a lump open and see a fossil coral there you realise that this fossil has been waiting there for over 300 mya – just waiting for you. Then you might come across some Triassic ( 250 – 201 million years ) and you start thinking that these rocks are fairly young. But when you see and archeologist on TV going on about “very old Roman finds that are two thousand years old”, you start to realise what deep time is. 

Then you might go to North West Scotland and place your hand on some Lewisean Gneiss and realise that it is over 3 Billion years old – two thirds of the age of the Earth. What a privilege to be able to see and touch these ancient rocks!

Language.

Geology is an international science so there are some lovely words to play with. Here are a few of my favourites.

Paleoproterozoic
Rhaetic
Solifluction
Slickenside
Batholith
Olivine
Wolfram.
Galena
Tourmaline
Subduction
Lithification

As a writer, I often use some of these words in stories, sometimes as the names of characters.

Is it any wonder that I love geology?

©  Eorðdraca 2018 My books are  here Richard

Author: Richard

I live in Somerset UK. I am a writer and geologist and blogger.

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