The final competition in Class 1 of the Year 11 course asked about the importance of dating volcanic eruptions, and the significance of tephrachronology in this process. We received some really fascinating entries in response to this question, many of which also address the applicability of these concepts to our current climate. You can read the winning entries and finalists below!
Competition 1.3: Telling the time with volcanoes
Can you think of reasons why we would want do date volcanic eruptions?
Can you think of some things that tephrochronology can help us with?
1st place: Leonardo Z.
The benefits of dating volcanic eruptions and tephrachronology
Tephrochronology, a method of researching volcanic eruptions by analysing tephra, and the dating of volcanic eruptions has multiple benefits. It allows us to better understand the climate and geography of the past, as well as providing more context on the sequence of geographical events or the extinction of different organisms.
One reason why we would want to date volcanic eruptions is the information we gain on the Earth’s history. The fossils of organisms can be analysed with the volcanic sediment or material around it to estimate the time period in which these organisms lived. Tephrochronolgy can also help us in a similar way to dating volcanic eruptions. The fossils within a layer of sediment that contains tephra from a certain volcanic eruption could allow us to identify the time period in which an organism lived and see if the volcanic eruption was the cause of their extinction or death.This would allow historians to better understand the progression of the Earth’s ecosystems and how significant and hazardous previous volcanic eruptions were.
Dating volcanic eruptions also allows us to prepare for future eruptions. By identifying patterns in the frequency of a volcano’s eruptions, it is possible to estimate when the next eruption will occur. For example, the Yellowstone supervolcano has been identified to have a major eruption every 725,000 years, allowing scientists to understand how significant a threat it is in the immediate future. Although eruptions can also be predicted by monitoring the volcanic activity within an area, it is possible that these signs of an eruption will occur too late, preventing sufficient preparations from taking place. Therefore, dating volcanic eruptions allows for better safety measures to be taken against volcanic eruptions, allowing nearby communities to be evacuated, warned or protected effectively.
Another benefit of tephrochronology is it provides a better understanding of the sequence of geographical events. Identifying layers of sediment and linking the tephra within them to a volcanic eruption will allow us to better understand whether an eruption occurred prior to or subsequently to another event by comparing the layers of sediment above and below it. Furthermore, by identifying tephra within multiple areas, we can better understand the past geography, as tephra from the same volcanic eruption in different geographical locations today could indicate that these locations were once relatively near to each other.
Finally, tephrochronology can help us to better understand the climate in the past. By identifying the tephra in a location and dating it back to a volcanic eruption, we can trace the route taken by the tephra, allowing us to speculate the strengths and directions of air currents at the time; the tephra would also likely have travelled a shorter distance in wetter conditions due to the causing the sediment to fall faster, giving us an idea of how wet or dry the climate was at the time of the eruption. This allows us to observe patterns in changes in the Earth’s climate, giving more insight into our impact on the climate.
2nd place: Seren B.
How Tephrachronology can Teach us about the Past and Prepare us for the Future of our Planet
Some reasons why we would want to date volcanic eruptions include using the age of the tephra to provide a time marker, giving a time frame for sedimentary sequences that contain a plethora of information that could deepen our understanding of the past and our planet.
For example, it could give us insights into past geographical events, enabling us to map extinction events that could lead us to discover why and when certain species went extinct, uncovering new knowledge of ecosystems of the past and advancing our knowledge of current ecosystems and how they work. One example of an extinction event is the Cretaceous–Paleogene extinction. This is the extinction that killed the dinosaurs and the effects can be seen in sedimentary rock. Tephrachronology could help us to date this extinction and to measure how long it took for ecosystems to recover and for new species to evolve and repopulate the Earth.
Giving a timespan to sedimentary sequences could also broaden our understanding of tectonic movement of the past. The dates of volcanic eruptions over millions of years could show how tectonic plates have shifted over time, for example an abundance of volcanic eruptions that are relatively close together and within a certain area could suggest large amounts of tectonic activity. Additionally, if we discovered tephra from the same volcanoes over a certain time frame, but spread over multiple areas, it would suggest that these places were once in the same area, but have separated over time, due to tectonic movement. This knowledge would increase our understanding of continental drift and how our planet has transformed over time.
Another aspect of tephrachronology is it allows us to map migrations of animals and plants through discovering fossils in sedimentary rock and working out when and where these fossils formed. Knowing where different species have moved over time allows us to understand how they have adapted to life in changing environments. Over time, the earth has gone through periods of warming and cooling which, along with other factors, has caused shifts in environments and ecosystems. If we can learn how plants and animals of the past have adapted to these changes, we can begin to understand how species today need to evolve to cope with the effects of global warming, or even if they are capable of it. This will allow us to simulate how our ecosystems will cope with climate change, providing essential information on changes that could occur as a result of extinctions and migrations.
In conclusion, tephrachronology gives us essential tools which allow us to map how our planet and ecosystems have shifted and evolved over time and in doing so it also gives us the power to simulate future changes to the Earth and its biosphere.
Thank you again to everyone who submitted entries to the Class 1 competitions; we had such a great time reading through them all and congratulations to all our winners! We’re looking forward to receiving many more fantastic entries for the Class 2 competitions–the deadline is 24 February so get your entries in by then! In the meantime you can peruse the Class 2 materials here.