When the Triassic entered onto the evolutionary stage some 251 million years ago, it did so on a low note. Its predecessor, the Permian, flamed out in a series of cascading natural disasters that left life hanging by a thread. The silver lining to this story was that the fittest survived, and when the planet returned to a more livable state, life had a clean slate on which to work its magic and embark on a new beginning.
At the end of the Permian, during an event called the “Great Dying,” 96 percent of marine species and 70 percent of terrestrial species disappeared, sucked down the black hole of mass extinction, never to return again. Their demise began when the earth belched out its molten core into the basalt flows that form the Siberian traps. Volcanic eruptions spat out lava for a million years and flooded the atmosphere with noxious greenhouse gases. Temperatures on land and in the oceans soared, and ocean acidification devastated the marine food chain. The onslaught was rapid and brutal, outpacing the ability of most species to adapt.
When the environmental devastation stopped, then evolution was left with a new opportunity to do what it does best, adapt and create. The Triassic began in unique circumstances with an underpopulated planet. Amongst the survivors of the “Great Dying” were the archosauriforms. They continued evolving during the Triassic, eventually starting the reign of the dinosaurs. The earliest dinosaurs (Nyasasaurus parringtoni) appear in the geological record about 243 million years ago. But they were comparatively small creatures and another 30 million years passed before a giant arose. Weighing in at 3 tons and up to 27 feet long, the Plateosaurus was a forerunner of the Jurassic monsters we are all familiar with. New species inevitably arise with a new beginning.
Things go amiss
The Triassic period lasted for about 50 million years, but it was not all peaches and roses. The planet earth is dynamic, continually changing, and challenging the ability of life to survive. This challenge was issued again during the Carnian Pluvial Episode (CPE) about 232 million years ago when a global warming episode pushed temperatures up by over 4 degrees Celsius. Heat, humidity, and intense storms changed life on land, and coastal marine reefs and ecosystems were wiped out by the heat and increased sedimentation. Climate change was in full swing, and species extinction rates climbed. The culprits for this disruption were large quantities of carbon dioxide and other greenhouse gases entering the atmosphere.
Our increasing awareness of today’s Anthropocene climate change makes this story uncomfortably familiar. True,
The Wrangellia large igneous province
An ancient oceanic plateau’s geological remains are found today in Alaska, Yukon, and British Columbia. This plateau formed long ago in Triassic oceans through eruptions of magma and flood basalts on an ancient ocean floor. The Wrangellia flood basalts are over 4000 feet thick. Today they are found in a mountain belt that runs along the Pacific Coast from Vancouver, Canada to Anchorage, Alaska. But initially, they probably covered an area of over half-a-million square miles in the
The Wrangellia eruptions occurred over several million years during the Carnian interval. As was the case with the Permian extinction, volcanic gases, not the magma, served as the instigator for climate change. The lesson from both Permian and Triassic extinctions are that rapid global warming disrupts existing ecosystems and devastates life through accelerated species extinction. The biosphere doesn’t care if the greenhouse gases are from natural or human sources, because the warming and environmental consequences are the same.
Rapid climate change stresses life, challenging its ability to adapt and creating winners and losers. The best a species can hope for is to come out on the winning side. But even though the winners survive, the journey to the other side is a trip through hell. A new beginning always comes at a cost.
Permian black shales (Source: ArcheanWeb) – https://archeanweb.com/2020/05/27/permian-black-shales/ Also:
Scientists Discover Oldest Known Dinosaur (By Riley Black; Smithsonian) – https://www.smithsonianmag.com/science-nature/scientists-discover-oldest-known-dinosaur-152807497/ Also:
Insights into climate change during origin of dinosaurs (Source: University of Utah; Phys Org) – https://phys.org/news/2020-07-insights-climate-dinosaurs.html Also:
A Climate Catastrophe Paved the Way for the Dinosaurs’ Reign (By PETER BRANNEN; The Atlantic) – https://www.theatlantic.com/science/archive/2018/10/dinosaurs-dolomites/573286/ Also:
The Accreted Late Triassic Wrangellia Oceanic Plateau in Alaska, Yukon, and British Columbia (By Andrew R. Greene, James S. Scoates, Dominique Weis; Large Igneous Provinces Commission) – http://www.largeigneousprovinces.org/08dec Also:
Feature Image: Triassic Landscape (Modified) – By Ghedoghedo – Own work, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=49647648