EGU Blogs

Extinction

Why I think the Jurassic/Cretaceous boundary is super important

This was originally posted here.

Mass extinctions are insanely catastrophic, but important, events that punctuate the history of life on Earth. The Jurassic/Cretaceous boundary, around 145 million years ago, was originally thought of to represent a mass extinction, but has subsequently been ‘down-graded’ to a minor extinction event based on new discoveries.

However, compared to other important stratigraphic boundaries, like the end-Triassic or the end-Cretaceous, both time periods representing mass extinction events, the Jurassic/Cretaceous (J/K) boundary actually remains really poorly understood. This is both in terms of what was going on with different animal groups at the time, and what environmental changes were occurring alongside this.

Well, I have a new research paper out now that synthesises more than 600 research articles, bringing them together to try and build a single picture of what was going on around this time! It’s free to read here, and is essentially the literature review from my thesis, or as I like to think of it, the justification for my existence as a researcher!

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Which palaeontology stories in 2015 captured the public’s imagination?

This was originally posted here!

Happy New Year everyone! It’s that time of year when all the summaries of an amazing year of research are coming out, and goodness, what a year it’s been! The folk over at Altmetric have been kind enough to summarise the top 100 articles of 2015, measured by their altmetrics scores – a measure of the social media chatter around articles. All the data are available on Figshare, and here I just wanted to highlight the palaeontology stories that stood out in the media this year according to the list.

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Molecular clocks and the End-Permian mass extinction

Earth’s history is punctuated by extreme events known as mass extinctions. The End-Permian extinction, 252 million years ago, is believed to be the biggest, killing 90 % or more of all species – no wonder it is also called “The Great Dying”. The big question out there is to understand what caused it, but it is a challenge to get the complete picture of an event so long ago in prehistory. We know that the Siberian Traps (the enormous field of volcanic rock that lies in Siberia) were formed around that time and that volcanic activity was a likely trigger for this mass extinction. But what actually happened? And why did so many species, including many groups of insects, disappear?

Last year, an article appeared that brought forward a new hypothesis. From evidence in rock cores, Daniel Rothman and co-authors [1,2] concluded that around the end of the Permian, a lot of organic carbon that was formerly trapped in the sediments was converted into CO2. This change happened so fast that its release was exponential.

When genes are passed on from microbe A to microbe B, both undergo a certain number of mutations per period of time.

When genes are passed on from microbe A to microbe B, both undergo a certain number of mutations per period of time.

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