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Saturday, May 31, 2014

Australia caused a mass extinction...

Sou | 6:04 AM One comment so far. Add a comment

History has a habit of repeating itself. Today Australia continues to burn coal like it was going out of fashion and it digs it all up and ships it off so that other countries can do the same. However this isn't the first time Australia has contributed to a mass extinction.

I came across an article in ScienceDaily.com about a new paper in the journal Geology that shows that Australia caused a mass extinction in the past. The long ago past. Around five hundred and ten million years ago if you want to be precise - or as precise as one can be when talking about events as long ago as that.

From the press release:
A Curtin University researcher has shown that ancient volcanic eruptions in Australia 510 million years ago significantly affected the climate, causing the first known mass extinction in the history of complex life.
Published in the journal Geology, Associate Professor Fred Jourdan from Curtin's Department of Applied Geology, along with colleagues from several Australian and international institutions, used radioactive dating techniques to precisely measure the age of the eruptions of the Kalkarindji volcanic province -- where lavas covered an area of more than 2 million square kilometres in the Northern Territory and Western Australia.
Dr Jourdan and his team were able to prove the volcanic province occurred at the same time as the Early-Middle Cambrian extinction from 510-511 million years ago -- the first extinction to wipe out complex multicellular life.
Earth was a bit different back then.  At that time Australia would have been part of Gondwana and there wasn't anyone around to take notes. The messages about what happened were written into the landscape by the events themselves. If you want to visualise the size of two million square kilometres, think Western Australia, which is 2.5 million square km. Or think three times the size of Texas, which is nearly 0.7 million square km. That was some volcanic complex.

What happened was that the climate oscillated a lot, cooling with all the sulphur dioxide and warming with all the CO2 and CH4. Lots of species disappeared never to be seen again, except maybe in fossils.

More from sciencedaily.com:
"We calculated a near perfect chronological correlation between large volcanic province eruptions, climate shifts and mass extinctions over the history of life during the last 550 million years, with only one chance over 20 billion that this correlation is just a coincidence," Dr Jourdan said.
Dr Jourdan said the rapid oscillations of the climate produced by volcanic eruptions made it difficult for various species to adapt, ultimately resulting in their demise. He also stressed the importance of this research to better understand our current environment.
"To comprehend the long-term climatic and biological effects of the massive injections of gas in the atmosphere by modern society, we need to recognise how climate, oceans and ecosytems were affected in the past," he said.

About the Kalkarindji continental flood basalt province


I came across this earlier paper by Linda Glass and David Phillips, that looks as if they named the Kalkarindji province and also made the link with the Early Cambrian extinction event. It was published in 2006 in the same journal. (David Phillips was a coauthor of the new paper, too.) Here is the abstract:
Extensive basaltic volcanism (>106 km2) occurred across northern and western-central Australia during Cambrian time. The basalts are geochemically distinctive, having unusually uniform elevated incompatible element signatures (high Th/U, La/Sm, Rb/Ba) that are atypical of most other continental flood basalt provinces. Individual volcanic and intrusive suites previously assigned to local stratigraphic units are shown to share a common parental magma.
This vast Cambrian igneous province is here named the Kalkarindji continental flood basalt province, Australia's oldest and largest Phanerozoic large igneous province. High-precision 40Ar/39Ar analyses of plagioclase feldspar separates from basalt flows yield ages of 508 ± 2 Ma and 505 ± 2 Ma (2σ), indistinguishable from previous U-Pb zircon ages for related dolerites.
These ages indicate that basaltic volcanism coincided with the Early-Middle Cambrian boundary and suggest a temporal link between eruption of the Kalkarindji basalts and the end-Early Cambrian (early Toyonian) faunal mass extinction event.

There aren't any comments from WUWT because the news article hasn't appeared there - or not yet anyway.  Anthony's too busy reblogging denier nonsense.  More on that later. I figured it might be nice to write about science for a change.


F. Jourdan, K. Hodges, B. Sell, U. Schaltegger, M. T. D. Wingate, L. Z. Evins, U. Soderlund, P. W. Haines, D. Phillips, T. Blenkinsop. "High-precision dating of the Kalkarindji large igneous province, Australia, and synchrony with the Early-Middle Cambrian (Stage 4-5) extinction." Geology, 2014; 42 (6): 543 DOI: 10.1130/G35434.1

Glass, Linda M., and David Phillips. "The Kalkarindji continental flood basalt province: A new Cambrian large igneous province in Australia with possible links to faunal extinctions." Geology 34, no. 6 (2006): 461-464. doi: 10.1130/G22122.1.


1 comment:

dbostrom said...

...there wasn't anyone around to take notes.
As well, nobody to argue that "C02 is only plant food and can't hurt you," or that "climate's changed before, no need to panic."
All quiet in the Predenskepitcon. :-)