Feeds

Volcanoes fingered in oceanic mass extinction

Dramatic late Cretaceous anoxic event

5 things you didn’t know about cloud backup

Scientists reckon they've confirmed what caused an oceanic mass extinction during the late Cretaceous period, 93 million years ago, provoked by a sudden, and previously unexplained "anoxic event" which deprived bottom-dwelling species of oxygen.

According to a report in Nature, the cataclysm was provoked by massive undersea volcanic eruptions in a plateau under the present-day Caribbean which "devastated animals living on the sea-floor such as foraminifera, millimetre-sized creatures that lie at the bottom of the oceanic food-chain".

While scientists had previously suspected a volcanic link to the extinction, Steven Turgeon, a geologist at Canada's University of Alberta, said: "What was missing was a clear link in the sedimentary record."

To make the case, Turgeon and colleague Robert Creaser looked at levels of two isotopes of osmium in sedimetary shale samples from the sea bed off South America and from mountains in Italy. They found that in both cases "the ratio of osmium-187 to osmium-188 dropped dramatically just before the extinction event", indicating "a huge amount of molten magma, carrying a higher proportion of the heavier isotope, was discharged into the oceans".

The figures represent, Turgeon said, a sudden and "astounding" 3,000–5,000 per cent increase in global volcanic activity. The Caribbean plateau was "the only volcanic site large enough to spew forth that much magma in the geologically-fleeting space of a few hundred of thousand years", the researchers concluded.

Tim Bralower, a marine geologist at Pennsylvania State University, agreed the study has "nailed the coffin shut" on the matter of whether the plateau was the source of the event, but noted that it remained to be proved quite what drove the mechanism of extinction.

Nature notes: "One theory is that minerals in the magma fertilized the ocean and led to a huge bloom of creatures that then died and decayed, sucking up oxygen in the process."

Of the eruption itself, Bralower added: "We really don't know why then or why there." He suggested the cause of the big bang "may lie in the mantle, or perhaps even at the outer edge of earth's core", and concluded: "That is now the $64 million dollar question." ®

Build a business case: developing custom apps

More from The Register

next story
Boffins ID freakish spine-smothered prehistoric critter: The CLAW gave it away
Bizarre-looking creature actually related to velvet worms
ANU boffins demo 'tractor beam' in water
The current state of the art, apparently
China to test recoverable moon orbiter
I'll have some rocks and a moon cheese pizza please, home delivery
NASA's rock'n'roll shock: ROLLING STONE FOUND ON MARS
No sign of Ziggy Stardust and his band
What does a flashmob of 1,024 robots look like? Just like this
Sorry, Harvard, did you say kilobots or KILLER BOTS?
Why your mum was WRONG about whiffy tattooed people
They're a future source of RENEWABLE ENERGY
Vulture 2 spaceplane autopilot brain surgery a total success
LOHAN slips into some sexy bespoke mission parameters
Another step forward for diamond-based quantum computers
Square cut or pear-shaped, these qubits don't lose their shape
LOHAN acquires aircraft arboreal avoidance algorithm acronyms
Is that an ARMADILLO in your PANTS or are you just pleased to see me?
prev story

Whitepapers

Endpoint data privacy in the cloud is easier than you think
Innovations in encryption and storage resolve issues of data privacy and key requirements for companies to look for in a solution.
Implementing global e-invoicing with guaranteed legal certainty
Explaining the role local tax compliance plays in successful supply chain management and e-business and how leading global brands are addressing this.
Top 8 considerations to enable and simplify mobility
In this whitepaper learn how to successfully add mobile capabilities simply and cost effectively.
Solving today's distributed Big Data backup challenges
Enable IT efficiency and allow a firm to access and reuse corporate information for competitive advantage, ultimately changing business outcomes.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.