When was permian extinction

The anoxic oxygen-lacking waters could have spilled onto the continental shelves, the high carbon dioxide content, toxic to marine life, poisoning much of the life in the oceans. At the same time, massive outpourings of volcanic basalt rock in what is now Siberia added huge amounts of heat, carbon dioxide, and sulfur dioxide to Earth's surface and atmosphere.

The carbon dioxide could have trapped heat in the atmosphere, and the resulting "greenhouse effect" generated a long warming trend. The climate change triggered by the warming could have shifted weather patterns dramatically, so that regions normally wet and rainy became dry and vice versa.

Geologic evidence supporting this hypothesis has been found in recent investigations in the Caledon River in South Africa. Did all these factors -- sea-level change, climate change, ocean stagnation, carbon dioxide buildup -- combine to cause the Great Dying?

We don't have all the answers. Clock December 06, Know your planet. Subscribe Stanford Earth Matters Magazine. Large quotation punctuation icon The conventional wisdom in the paleontological community has been that the Permian extinction was especially severe in tropical waters. Navigate to item. Hannah Hickey University of Washington , hickeyh uw. Justin Penn University of Washington jpenn uw. Explore more. Wildfire smoke exposure during pregnancy increases preterm birth risk, study finds Smoke from wildfires may have contributed to thousands of additional premature births in California between and Navigate to Wildfire smoke exposure during pregnancy increases preterm birth risk, study finds.

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A forest once grew here. Half a mile 0. No birds called, no insects hummed. The only sound was the wind through the acid-tolerant weeds. Looy picked up a spruce cone.

Pollen from the trees around us might be preserved inside. She believes that the Permian extinction was caused by acid rain following a massive release of volcanic gases. She wants to compare tree pollen from a modern forest killed by acid rain with fossil pollen found in Permian rocks.

Like a homicide detective at a crime scene, Looy sealed the cone in a plastic bag for later lab work. Looy is one of many scientists trying to identify the killer responsible for the largest of the many mass extinctions that have struck the planet. The most famous die-off ended the reign of the dinosaurs 65 million years ago between the Cretaceous and Tertiary periods.

Most researchers consider that case closed. Rocks of that age contain traces of an asteroid that struck Earth, generating catastrophic events from global wildfires to climate change.

But the Permian detectives are faced with a host of suspects and not enough evidence to convict any of them. To understand this extinction, I wanted first to get a sense of its scale. That's difficult—sediments containing fossils from the end of the Permian are rare and often inaccessible. One site that preserves the extinction's victims lies about a half day's drive inland from Cape Town, South Africa, in a scrubland known as the Karoo.

We ascended through sheep-ranching country toward the Lootsberg Pass. The rocks that surrounded us date from the late Permian. For every yard of altitude we gained, we traveled tens of thousands of years forward in time, heading for the Permian's conclusion. If we had driven here before the extinction, we would have seen animals as abundant and diverse as those of today's Serengeti, except most would have belonged to a group known as synapsids. Often called mammal-like reptiles—they looked like a cross between a dog and a lizard—the synapsids were Earth's first great dynasty of land vertebrates.

They were preyed upon by gorgonopsians—fleet-footed synapsid carnivores with needle-sharp teeth. The late Permian rocks we passed as we neared Lootsberg Pass capture the synapsids at the height of their reign. For more than 60 million years they were Earth's dominant land vertebrates, occupying the same ecological niches as their successors, the dinosaurs.

Smith slowed at a switchback, rolled down the window, and pointed to a horizontally banded cliff. Brace yourself, you're about to go through the extinction. A synapsid known as Lystrosaurus appears in these sediments. Smith had a skull of the animal in his truck. Its flat face gave it the look of a bulldog with tusks.

In the first few yards of the transition zone, only one or two Lystrosaurus fossils have been found scattered among all the diverse late Permian animals. Higher up, the diversity suddenly dwindles. Dozens of species of Permian synapsids disappear, leaving Lystrosaurus and a few others in early Triassic rocks.

Animals were still abundant, but the community they formed was about as species rich as a cornfield. Plants were also hit by the extinction. Evidence for the scale of damage to the world's forests comes from the Italian Alps. I joined a research team led by Henk Visscher of the University of Utrecht at the Butterloch gorge, where exposed fossil beds cover the transition from the Permian to the Triassic.

The beds lie high on a cliff, accessible only by climbing piles of debris. I anxiously followed veteran climber Mark Sephton up a slope of loose rocks to a ledge. Sephton used his hammer to chip bits of rock from the layers that chronicle the extinction. The formation of Pangaea may have also had an effect on ocean circulation which in turn affected nutrient circulation in the oceans, and may have also affected global weather patterns.

Another possible cause of the extinction is an impact event, much like the meteor that famously killed the dinosaurs at the end of the Cretaceous Period. The Permian extinction appears to have happened in two or three pulses of extinction. Two or more separate impacts could have possibly accounted for these pulses.

Some possible evidence for impact events are meteorite fragments in Australia, rare shocked quartz in both Australia and Antarctica, and craters in Australia. If a meteor did impact Earth during this time, it more than likely landed in the ocean. Since the ocean floor is recycled by tectonic activity every million years, any evidence of the impact is likely gone.

The most likely scenario is that the Permian mass extinction was caused by a combination of many events which together made the Earth unsuitable for most life. It is important for scientists to try to understand the conditions during the Permian mass extinction because it will help them to better understand the climate crisis we are currently facing and possibly help take measures to avoid another mass extinction event in the future.

Encyclopedia Britannica: Permian Period. Encyclopedia Britannica: Permian extinction. Jackson Chambers Writer. All Posts. Julio Lacerda Staff Artist and Writer.