Rocks, Fossils and Formations: A story 4.6 billion years in the making
Rocks, Fossils and Formations takes readers on a 4.6 billion year time travel adventure and explores the stories of rocks, minerals and fossils.
Have you ever wondered about the rocks under your feet? The sand at the beach, the stones used to build houses, or the precious gems in jewellery? The stories of our landscapes and the rocks and minerals that are part of everyday life can be billions of years in the making.
Written by Thomas R. H. Woolrych and illustrated by Anna Madeleine Raupach, Rocks, Fossils and Formations: Discoveries Through Time is an introduction to geoscience for budding geologists. The book explores the history of the Earth and the evolution of life through geological time, delving into the age of the Earth, the rock cycle, volcanoes, plate tectonics, and the formation of precious metals and gems.
In this edited extract from the book, Thomas shares what geoscience is and how it can help us peer into Earth’s distant past.
Travel 4.6 billion years back in time and discover the story of Earth. (Illustration: Anna Madeleine Raupach, Rocks, Fossils and Formations)
Have you ever been at a park, beach or nature reserve and noticed a strange and beautiful rock? How old could it be? How did it get its colour and texture? Might it hold some rare mineral or fossil treasure? Geoscientists read the clues in rocks and the landscape to tell the story of Earth. It’s a story so old and so fascinating that you might think it were made up – if the evidence wasn’t there for us to see!
What is geoscience?
Geoscience is the study of Earth and all the systems that affect it. A geoscientist is someone who studies Earth and the systems that affect it by deciphering the clues hidden within rocks. Despite what you might see on TV or online, you don’t have to be an old man with a grey beard and sandals to be a geoscientist. You simply have to be interested in Earth! Modern geoscience is a broad subject for anyone. It covers bits of chemistry, physics, biology, paleontology (the study of fossils), natural history, cartography (mapping), and even coding and computing. Some of the latest techniques include machine learning and artificial intelligence.
One of the most important ideas in geoscience is that processes you can see going on today in the natural world are occurring in the same way they always have – even in the distant past! Natural processes happening right now, such as the wind blowing around sand, rocks rolling down hills, rivers carving through valleys, waves breaking on the beach, volcanoes exploding, earthquakes and floods, have been (mostly) occurring in the same way since the formation of Earth.
This means that our present is the key to the past. This idea was radical when Western scientists first proposed it, because most people had understood Earth through creation stories in philosophy and religion. For example, they read about Noah’s Ark and the great flood, and then looked for evidence of mega floods within rock layers.
Our present is the key to the past.
Through careful observation, people slowly began to accept the fact of an ancient Earth. Geoscientists noticed that the layers of a rock known as sandstone are made by laying down many particles of sand, grain by grain. Next time you are outside, try picking up a single grain of sand between your fingers. It’s small, right? Now scale that up from a layer of rock to rock outcrops; they are made up of many layers of rock.
Geoscientists who first attempted this exercise using simple maths and thought experiments realised that any one rock outcrop could take millions of years to form! They studied more and more rocks, rock layers and rock outcrops in different areas all over the world. With each discovery, the age of Earth was pushed back by millions of years.
When Marie Curie discovered radioactive decay in 1898, we gained a sort of ‘rock clock’ to calibrate the timing of the formation of rock layers. Today’s best date for the age of Earth is 4.54 billion years!
The rock cycle involves three main groups of rocks – igneous, sedimentary and metamorphic – which form by different processes. (Illustration: Anna Madeleine Raupach, Rocks, Fossils and Formations)
But what does all this mean for us? Have a close look at your hand. It’s made up of skin, muscle, blood and bones. All of these are made up of cells containing your DNA – a biological set of instructions on how to build your body. Your DNA was passed to you by your parents, and tells the story of you. But it also tells a much, much bigger story that goes back billions of years.
The unbroken chain of inheritance from parent to child leads back to the beginnings of life. Isn’t this a marvellous thought! Every one of your ancestors has successfully reproduced and passed on their DNA, going all the way back to single-celled organisms in a warm pool of water on early Earth billions of years ago. You are a product of time, physics and evolution. And as a geoscientist would argue, you are also a product of the rocks at your feet.
You are a product of time, physics and evolution. And as a geoscientist would argue, you are also a product of the rocks at your feet.
So, what do rocks tell us? What fossil and mineral treasures have been dug up so far, and what answers do they hold? Let’s start our Earth origin story time-travel adventure! It all began in a cloud of gas and dust in the early solar system, in a time known as the Hadean …
Earth began its life in the Hadeon Eon (4600–4000 million years ago) as a molten ball of lava that cooled over millions of years. (Illustration: Anna Madeleine Raupach, Rocks, Fossils and Formations)
This is an edited extract from Rocks, Fossils and Formations: Discoveries Through Time, which takes readers on a 4.6-billion-year-long time travel adventure to explore rocks, minerals and fossils, meet ancient plants and animals, and discover how the continent of Australia was created. This introduction to geoscience is perfect for curious kids aged 9 to 14.
Get your copy of Rocks, Fossils and Formations online or find it at your local bookshop.
Thomas R. H. Woolrych. (Photo: supplied)
About the author and illustrator
Thomas R. H. Woolrych is a science communicator and exploration geoscientist with a passion for discovering the secrets of the Earth. He enjoys sharing this passion and looking for minerals.
Anna Madeleine Raupach is a multidisciplinary artist based on Ngunnawal, Ngambri country, Canberra. Her practice spans drawing, moving image, installation and digital media to explore expressive interpretations of scientific concepts.