Hey, have you heard the news? A stunning revelation has just surfaced out of southern China: a gigantic chain of extinct volcanoes sitting beneath the Sichuan Basin! This incredible geological find stretches for over 400 miles and is believed to be nearly 800 million years old, holding secrets of Earth’s lush history.
Students of geology might want to sit down for this one—research suggests that these volcanoes likely originated during the tumultuous breakup of the ancient supercontinent Rodinia, a massive tectonic event that created a gigantic volcanic structure. What’s fascinating is how this chain has been covered for so long, buried beneath layers and layers of sediment until now.
Up until now, the Sichuan Basin has been sort of a quiet zone in geological terms. However, researchers, including Zhidong Gu from PetroChina and Junyong Li from Nanjing University, believe this ancient volcanic arc could change how we understand tectonic history on early Earth. Their fascinating findings have just been shared in the Journal of Geophysical Research: Solid Earth.
Unearthing Secrets with Magnetic Data
The whole adventure kicked off with some pretty high-tech airborne magnetic surveys. Imagine X-ray-like vision—but for the ground beneath us! These cutting-edge sensors detected a mysterious magnetic anomaly about 6 kilometers (4 miles) down, indicating the presence of an extensive iron-rich rock belt running an impressive approximately 430 miles (700 km) from northeast to southwest beneath the Yangtze Block.
This isn’t the type of discovery geologists see on a regular basis. By drilling down through seven deep boreholes, scientists found materials that looked just like typical arc volcanism. These are the same kinds of rocks that form when magma rises up from a subducting oceanic plate, which is just how it’s supposed to work. The raft of rocks was dated to between 770 and 820 million years ago, dropping us deep into the early years of the Neoproterozoic era, as detailed by Live Science.
What blows my mind is just how far inland these volcanoes go. These geological features are normally found close to continental edges, not hundreds of miles from the nearest shores!
A Unique and Expansive Volcanic System
So you’re wondering, how did a volcanic arc end up so far from the coast? Well, researchers think it’s tied to a concept known as flat-slab subduction. This is where the oceanic plate slides under the continent at an almost horizontal angle before descending even deeper into the Earth. This tectonic process creates not one, but actually two parallel volcanic belts: one right at the edge and one much farther inside.
According to the study, this action closely resembles what’s currently going on along the west coast of South America, where the Nazca Plate is slipping underneath the continent, resulting in the majestic Andes Mountains. In this case with ancient China, a similar story played out, just in an immensely older—or we can say fossilized—format.
However, some experts have their reservations. Peter Cawood, a geologist from Monash University in Australia, has pointed out that this may not be just one single extensive system. He suggests that there could be two different volcanic systems that formed at the same time but eventually combined. In his view, the system might be two separate arcs rather than one lengthy one, which could change the whole narrative around this discovery.
Exploring Volcanoes’ Impact on Climate
This fascinating volcanic belt originated during a period of massive geological and environmental evolution, specifically when significant changes were sweeping the planet’s carbon cycle, which occurred about 720 million to 1 billion years ago. Volcanoes are known for spewing out carbon dioxide, and while mountain-building and erosion act to pull that gas back, they play critical roles in shaping Earth’s climate over time.
Even though it remains unclear just how this ancient Chinese volcanic formation affected its time period, the discoveries are igniting crucial discussions among the scientific community. Was it pushing the atmosphere’s warmth with its emissions? Or did it possibly cool the climate by spurring accelerated mountain erosion? This new find indeed shines a spotlight on an ancient epoch that has slumbered beneath layers of time for hundreds of millions of years.
Liked what you read?Sign up for our free newsletter to get more captivating stories and essential updates!
