Monday, January 06, 2020

Set on Stone : Book Review

Set on Stone- The geology and landscapes of Scotland by Alan Mckirdy

While visiting the Dynamic Earth a few years ago in Edinburgh with kids, it gave me the background to on our dynamic planet and its formation.  Most importantly, I came to know that "the Geology as field originated in Edinburgh" during the period of the Scottish Enlightenment.  Since then, we have annual memberships for our family to Dynamic Earth for the last couple of years and it is our favorite family activity that is weatherproof :-).  If you are visiting Edinburgh and you have some basic interest in science then Dynamic Earth is a must-visit for your family. 

I came across this book in the bookstall of Dynamic earth, I was intrigued by the details, but I  did not buy it  instead decided to borrow and read from the local library :-).  
The first chapter not only gives the background of the formation of the earth but also the background on originations of the field of Geology. 
As mentioned in chapter-1 of the book, the belief that the earth was about 5000 years old was propagated by the Church and was prevalent in Europe.  In fact, James Usher, the Church of Ireland Archbishop even had a date of 4004 BC (1).

It was James Hutton Scotland's first 'time lord', who discovered from rocks that the earth is much older than that and also brave enough to contradict then established belief propagated by Chruch saying that 'the rocks don't lie'. It was a revolutionary discovery at that time. 

In 1785, Hutton traveled across the country to develop his masterwork "Theory of Earth".  His trips revealed that there were rocks that were older than granite.  

In 1795, Hutton published his 2 volume work "Theory of Earth with proofs and illustrations". The book does not mention the fact but when Charles Darwin went on a voyage around the world on HMS Beagle that helped him to form the theory of evolution,  this book "The theory of Earth" was one of the few books he carried with him. 

All of us now know today that the fact that tectonic plates move (continental plates) but the scale and path traveled by some of some landmasses is a revelation.  This book focuses on Scotland, so it has identified that Scotland was originally near the South Pole 650 million years ago and to the present day location in the northern hemisphere. The journey and path over the last 650 million years have been recorded in rocks.  The Indian in me wishes that "how wonderful if someone performs such detailed study for different parts of India". We have the Himalayas, i.e. one of the oldest mountains on the planet, it will be a wonderful study that will benefit humanity. 

The book also plot the geological map of Scotland colored with different ages of rocks found in a different part of Scotland.  Scotland is unique and even blessed to have different varieties of rocks of different ages located in a relatively small area of geography. 

Again, I wanted to know whether such a study or geological survey was performed in India.  My limited study revealed that the work in this area in India seems very limited(2). It was disappointing again. India, a huge country and an ancient civilization with different geographies, we have not mapped our geology to the greater details. 

There are commercial incentives for performing such a study as it will open up new avenues in Agriculture &  Mining that will, in turn, open up other industries. Its high time such a detailed geological survey is done to understand the land and rocks in India.

Chapter-2: again talks in detail about Scotlands past inferred from different rocks.

Chapter-3: Volcanic past. Earth had an active volcanic period that cooled down and making most of the volcanoes extinct. The past volcanic activity is recorded in igneous rocks. This chapter gives an overview of different mountains in Scotland that have recorded the volcanic activity of the past. 

Chapter-4: This is a generic chapter that gives an overview of the earth's past with some references to Scotland.   The earliest trace of life in Scotland rocks dates back to about 1 billion years with traces of early algae.  The red sandstones of Torridonian Hills of Northwest Scotland carry these early algae.  This early life forms very primitive but had a remarkable quality that they produced oxygen. They changed the atmosphere of earth paving the way to much-specialized organisms later. This set the scene for the 'explosion of life' during the Cambrian Period. At his time the life on Earth was confined to oceans. (sounds familiar - our Matsya avatar :-)). Then a period of life on land came much later. So does our Koorma, Varaha avatars) :-). The period of time from this point onwards to the present day is 'Phanerozoic'.  This is the last 545 million years of earth history when life was abundant on planet earth. 
The five mass extinctions so far:
  1. At the end of the Ordovician period about 444 million years ago. 
  2. At the end of the Devonian Period about 359 million years ago.
  3. At the end of the Permian Period about 251 million years ago.
  4. At the end of the Triassic Period about 200 million years ago. 
  5. At the end of the Cretaceous Period about 65 million years ago. (hugely popular as dinosaurs become extinct)
My moral of these extinctions as we are at the due for the next major extinction is follows: Earth is resilient. It will adjust itself and life will move on but unless we humans treat the mother earth with respect, we as a species might become extinct in the next extinction, whenever it happens.

People who travel across UK will realize that Scotland is different from the rest of UK even geographically.  During Cambrian Period (i.e 495-545 million years ago) Scotland was part of the North American Continent whereas England and the rest of Europe were on the other side of Iapteus ocean.  The book does not state this but it's worth noting that land masses Eastern Avalonia collided with Laurentia about 425 million years ago, joining England and Scotland. Scottish Nationalists can quote this as another reason for independence, stating that Scotland was different from UK even going back 500 millions of years ago :-)
The rest of the chapter covers Scotland's journey during different periods including the time when it was submerged under the ocean.

It is interesting and even hard to imagine towering Scottish Munroe's underwater.  That's the beauty of our dynamic and ever-changing earth.

Chapter-5 talks about the geological legacy's influence in today's Scotland. Soil development is limited across many parts of Highland and very thin supporting only heather and hardy plant species.

Amazing book a must-read for anyone interested in science. 

2. Geological Survey of India.