The incredible self generating story of the Earth pulling itself out of its last ‘Snowball Earth’, and bringing with it the environment to allow complex life to thrive on land. This extensive body of work illustrates the stunning transformations that took place in Earth’s land, air and seas and should help advance our understanding of how life on the blue planet has diversified.
Decoding a thawed Snowball Earth
Just picture this ball of a planet locked within the ice within glaciers up to a kilometre thick covering almost any last inch on its surface. This severe climatic event, referred to as ‘Snowball Earth,’ has come about just a few times in the history of our planet — sometimes up to hundreds of millions and even scores of million years.
The most recent Ice Ball Earth event, which took place just over 640 million years ago, has been a riddle for the age. Ultimately, how did our planet rise out of that 4km high pile of ice, and what changes took place? Research led by the University of Washington offers a better roadmap of conditions and timing for when fresh water is counted, factoring in greater variability that characterized earlier studies New research from the University of Washington provides a more comprehensive understanding of this critical transition.
Researchers have peered into the precipitous past and now offer a way forward that could help usher in better environmental stewardship. Discovered at sites worldwide, these distinctive sedimentary rocks are the clue to decoding the intricacies of our planet’s response as it emerged from a frozen state.
A Remarkable Aftermath To Snowball Earth
Based on the evidence gleaned from rocks in northern Svalbard, which show eroding mountain ranges and moulins cut into glaciers that suggest melting ice (above left), a detail of black shales deposited as sea levels rose (center) and tectonic plates colliding to form mountain belts would push continents closer to the equator.
Originally, the melting of large ice sheets generated a freshwater lens atop denser, saltier ocean water, causing a stratified ocean. This, in turn, slowed the circulation of the ocean and caused changes to gas exchange between atmosphere and deep ocean.
As these changes proceeded, the churning of the ocean transferred deep-ocean heat to its upper levels and once again atmospheric perturbations led to a deep ocean response. Important changes in the oceans temperature, acidification and circulation ensued that influenced all life on Earth.
What is strikingly interesting is that, in the billion years before Snowball Earth, life on Earth persisted primarily as single-celled microbes and algae. Yet not long after the final Snowball Earth event, in the fossil record appear more sophisticated animals and things begin kicking off on our planet.
That brings up a fascinating question: could the enormous changes that took place after Snowball Earth have opened the door for life to evolve on our planet? This new study sets the stage for an investigation into how those changes may have facilitated well-fueled animals to emerge in a world fraught with environmental tumult.
Conclusion
Conversely, the findings about the most recent Snowball Earth reveal a dramatic past for the planet. Spinning the intricate changes of the Earth’s atmosphere, oceans and climate into focus, this study well not only provides detail on an important episode in our planet’s history but also offers clues as to how these events might have contributed to the rise of multicellular life. As scientists work to unravel the complex links between global climate change and life’s extinctions and raging dynamics, this new study is providing valuable data on how key aspects of our planet have evolved over time.
