Nav: Home

The secret of the supervolcano

January 26, 2017

Researchers have now found an explanation for what triggered the largest volcanic eruption witnessed by mankind. The volcano's secret was revealed by geochemical clues hidden inside volcanic quartz crystals.

The deadliest volcanoes on earth are called supervolcanoes, capable of producing cataclysmic eruptions that devastate huge regions, and cause global cooling of the climate. The Indonesian supervolcano Toba had one of these eruptions about 73000 years ago, when 2800 cubic kilometers of volcanic ash was ejected into the atmosphere and rained down and covered enormous areas in Indonesia and India.

Scientists have long debated how these extraordinary volumes of magma are generated, and what makes this magma erupt so very explosively. A team of researchers at Uppsala University, together with international colleagues, have now found intriguing clues hidden inside millimeter-sized crystals from the volcanic ash and rock.

'Quartz crystals that grow in the magma register chemical and thermodynamical changes in the magmatic system prior to eruption, similar to how tree rings record climate variations. When the conditions in the magma change, the crystals respond and produce distinct growth zones that record these changes. The problem is that each "tree ring"-analogue is only a few micrometers across, which is why they are extremely challenging to analyse in detail,' says Dr. David Budd at the Department of Earth Sciences, Uppsala University.

The researchers analysed quartz crystals from Toba, and found a distinct shift in the isotopic composition towards the outer rim of the crystals. The crystal rims contain a relatively lower proportion of the heavy isotope 18O compared to the lighter 16O.

'The low ratio of 18O to 16O contents in the crystal rims indicate that something in the magmatic system changed drastically just before the big eruption. The explanation behind these chemical signatures is that the magma melted and assimilated a large volume of a local rock that itself is characterised by a relatively low ratio of 18O to 16O . This rock type also often contains a lot of water, which may be released into the magma, producing steam, and thereby an increased gas pressure inside the magma chamber. This rapidly increased gas pressure eventually allowed the magma to rupture the overlying crust, and send thousands of cubic kilometres of magma into the atmosphere,' explains Dr. Frances Deegan at the Department of Earth Sciences, Uppsala University.

Luckily, these cataclysmic super-eruptions happen very rarely.

'Biologists have previously shown that this particular eruption at Toba pushed humanity close to extinction. It will hopefully take many thousands of years, but the fact is it is only a matter of time before the next super eruption, maybe at Toba, Yellowstone (USA), or somewhere else. Hopefully, we will know more and be better prepared next time!' says Professor Valentin Troll at the Department of Earth Sciences, who led this study of Toba quartzes at Uppsala University.
-end-


Uppsala University

Related Climate Articles:

Climate change label leads to climate science acceptance
A new Cornell University study finds that labels matter when it comes to acceptance of climate science.
Was that climate change?
A new four-step 'framework' aims to test the contribution of climate change to record-setting extreme weather events.
It's more than just climate change
Accurately modeling climate change and interactive human factors -- including inequality, consumption, and population -- is essential for the effective science-based policies and measures needed to benefit and sustain current and future generations.
Uncertainties related to climate engineering limit its use in curbing climate change
Climate engineering refers to the systematic, large-scale modification of the environment using various climate intervention techniques.
Public holds polarized views about climate change and trust in climate scientists
There are gaping divisions in Americans' views across every dimension of the climate debate, including causes and cures for climate change and trust in climate scientists and their research, according to a new Pew Research Center survey.
Incubating climate change
A group of James Cook University scientists led by Emeritus Professor Ross Alford has designed and built an inexpensive incubator that could boost research into how animals and plants will be affected by climate change.
And the Oscar goes to ... climate change
New research finds that Tweets and Google searches about climate change set new record highs after Leonardo DiCaprio's Academy Awards acceptance speech, suggesting celebrity advocacy for social issues on a big stage can motivate popular engagement.
Cod and climate
Researchers use the North Atlantic Oscillation as a predictive tool for managing an iconic fishery.
What hibernating toads tell us about climate
The ability to predict when toads come out of hibernation in southern Canada could provide valuable insights into the future effects of climate change on a range of animals and plants.
Maryland climate and health report identifies state's vulnerabilities to climate change
A new report by the University of Maryland School of Public Health and the Maryland Department of Health and Mental Hygiene details the impacts of climate change on the health of Marylanders now and in the future.

Related Climate Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Moving Forward
When the life you've built slips out of your grasp, you're often told it's best to move on. But is that true? Instead of forgetting the past, TED speakers describe how we can move forward with it. Guests include writers Nora McInerny and Suleika Jaouad, and human rights advocate Lindy Lou Isonhood.
Now Playing: Science for the People

#527 Honey I CRISPR'd the Kids
This week we're coming to you from Awesome Con in Washington, D.C. There, host Bethany Brookshire led a panel of three amazing guests to talk about the promise and perils of CRISPR, and what happens now that CRISPR babies have (maybe?) been born. Featuring science writer Tina Saey, molecular biologist Anne Simon, and bioethicist Alan Regenberg. A Nobel Prize winner argues banning CRISPR babies won’t work Geneticists push for a 5-year global ban on gene-edited babies A CRISPR spin-off causes unintended typos in DNA News of the first gene-edited babies ignited a firestorm The researcher who created CRISPR twins defends...