End-Permian Extinction Due to Contact Metamorphism?

David Middleton

Here’s a novel take on the Siberian Traps and the End-Permian extinction:

Geology

Massive underground magma pulse caused the world’s largest mass-extinction

The end-Permian wiped out almost all marine species

Geologists have suggested that Earth’s most severe mass-extinction was caused by a huge pulse of magma which released deadly levels of greenhouse gases into the atmosphere.

In a Nature Communications paper entitled “Initial Pulse of Siberian Traps Sills as the Trigger of the End-Permian Mass Extinction,” the team suggests that a huge magma pulse wiped out 95 per cent of marine species and 70 per cent of land species 252 million years ago.

The end of the Permian period coincided with an abrupt change from dominantly flood lavas to sill intrusions, a type of intrusive igneous rock (rock that has solidified from lava or magma).

In a region known as the “Siberian Traps”, a huge pulse of magma rose up through the Earth, and instead of erupting on the surface, it spread throughout the Earth’s crust, creating a vast network of rock stretching across almost one million square miles.

The magma then solidified between older layers of sedimentary rock into geological formations known as ‘sills’.

Extreme heat from these sills led to ‘contact metamorphism’ (alteration of the composition or structure of a rock by heat or pressure) of carbon-rich rocks.

This released dangerous levels of carbon dioxide, methane and sulphur dioxide into the environment and triggered the end of the Permian period.

[…]

Rest of story here:Wired

Interesting hypothesis.

Unfortunately the Wired article concludes with a totally idiotic paragraph:

This paper gives an insight into millennia-old conditions which have impacted our environment today. During the end-Permian, the biosphere couldn’t protect itself against the sudden, large emission of greenhouse gases, leading to a continual elevation in sea surface temperature across the globe.

And a prominent link to a dreadfully idiotic article:

Whatever caused the End-Permian extinction, it was a really bad thing or bad series of things.  For anyone who thinks that “Earth has entered a sixth mass extinction event,” please read this article: Earth Is Not in the Midst of a Sixth Mass Extinction.

Geology Info:

Traps refer to trap rock.  Trap rock is any fine grained non-granitic igneous rock.   Basalt, peridotite, diabase, and gabbro are types of trap rock.  The Siberian Traps and Deccan Traps were the result of flood basalt events, massive basaltic eruptions.

Sills are shallow igneous intrusions which are generally conformable with sedimentary bedding planes.   Dikes are intrusions which are not conformable.  Basalt and diabase are respectively the extrusive and shallow intrusive versions rocks formed from basaltic magmas.

The Hudson River (AKA New Jersey) Palisades is a diabase sill:

Contact metamorphism is what happens when a hot magma body comes into contact with much cooler rocks near the Earth’s surface.