Geeky Goodness from the Fossil Huntress — Palaeo Sommelier. If you love palaeontology, you'll love this podcast. Learn about fossils, head out on palaeontological excavations and meet awesome palaeo folk in bite-size bits. You are welcome to check out the Fossil Huntress Blog ARCHEA at www.fossilhuntress.blogspot.com where you'll find musings meant to captivate, educate and inspire — plus some epic fossil photography.
Geologic Time & the Periodic Table
Part of our ability to date the rock sequences we see in the world and determine which are older and which younger has to do with simple observation. We see that older rocks contain trilobites and a wee bit above those we see ammonites, then clams and oysters in newer sediments. For a long time, this simple observation held us in good stead. We had a relative timescale for the Earth and this allowed us to piece together the biologic and geologic picture much clearer.
To understand and date rock in absolute terms required advances in science, in chemistry in particular, that we achieved in large part by 1895. This was the beginning of our understanding of distinct elements and the periodic table of elements. To many, the table is a memory of science classes from our youth and long forgotten. But in the period table, we find both the tremendous history of human achievement and the aha moments that help us to understand simple yet complex concepts like radioisotope decay — the genius tool we use for the absolute dating of rocks and fossils.
To that end, I highly recommend Sam Kean's book, The Disappearing Spoon. It is a tasty romp through madness, love and the history of the world through the eyes of the periodic table. You may find that within the stories that the table becomes more real for you and that the mysteries it holds are more easily within your grasp.
The Map that Changed the World
Our World has shifted dramatically over time. Our great land masses and oceans have moved, grown, shrunk, come together and pulled apart over the Earth's history. It is the fossils that have helped shape our understanding of this tremendous story of upheaval. Part of understanding fossils has been simple observation. We find fossilized shells on mountain tops — quite unexpectedly — and this makes us question how this could be possible.
As we learn about plate tectonics and palaeogeography, we also observe collections of fossils and what they tell us about ancient climates, distribution of species and life on Earth over time. I find textbooks very useful as a means to gain an understanding of these concepts. I also love a great story and highly recommend the work of Simon Winchester. He's written many a great tale. I thought you might enjoy one of them on the life of William Smith, the father of modern geology — The Map that Changed the World.
Alberta Fossil Field Trip
Alberta is a gorgeous province in western Canada that borders British Columbia & Saskatchewan. Here you can see the glorious Canadian Rocky Mountains, Beautiful Wildlife & the Badlands with their Dinosaur remains.
Fossils Deep in the North Sea
Brown Bank in the North Sea is a treasure trove of Miocene and Pleistocene Fossil Mammal material. It is also a great place to unearth archaeological remains. Until sea levels rose at the end of the last Ice Age, between 8-10,000 years ago, an area of land connected Great Britain to Scandinavia and the continent. Here our relatives lived their lives, hunted local animals and all species left remains behind.
This region is now underwater in the Brown Bank section of the North Sea. The North Sea is a sea of the Atlantic Ocean located between the United Kingdom, Denmark, Norway, Germany, the Netherlands, Belgium and France. An epeiric sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north. Trawl nets are used to scoop up fish and often turn up interesting fossils and artefacts from the deep seabed.
Mass Extinction Events
We have had Five Mass Extinction Events in the Earth's 3.5 billion year history. These are cataclysmic events where more than 75% of the Earth's species have become extinct. The most recent of these is the Cretaceous mass extinction where we lost the dinosaurs, our mighty marine reptiles and beloved ammonites.
Geologic Time & Radioisotope Dating
We live on an amazing planet with a 4.5 billion year history of life evolving from a single cell to multicellular life to the sheer volume of diversity of species we see through time and walking the Earth today. How do we know the timeline for this? How do we date the rock units and mountains and stones beneath our feet?
We use simple observation out in the field to look at rock and observe that generally speaking, older rock units tend to be deeper than the younger rock on top. We use index fossils like ammonites or Triassic paperclams to help give us a better understanding. We also turn to chemistry and use the decay rates of radioisotopes to help give us a time stamp on a rock unit. We use Carbon-14 for rock younger than 50 thousand years or Potassium-40 or Uranium for rock older than 50 thousand years. It was through the decay rate of uranium that we arrived at a relative age of the Earth of 4.5 billion years.
We have new techniques evolving out of various fields of science to help us gain a deeper understanding of the Earth. Donald Prothero has been taking deep-sea drilling cores which tell us of shifts in the magnetic field of the Earth. His work will let us date the fossils we find to within 100,000 years — a significant insight over the plus or minus 2-million-year dating that radioisotopes give us.