Unveiling the Origins of Continents and Life on Earth: Ancient rocks in China and South Africa reveal a crucial moment in Earth’s history, shedding light on when rivers began pouring nutrients into the sea.
The discovery of ancient rocks in China and South Africa has shed light on a crucial moment in Earth’s history: the emergence of continents and the subsequent delivery of nutrients from land to ocean. The findings, published in the journal Geology, indicate that rivers may have operated on a global scale around 3.5 billion years ago.
Ancient rocks are formed through a process known as plate tectonics, where the Earth's crust is broken into large plates that move and interact with each other.
These interactions can cause rocks to be compressed, melted, or deformed, resulting in the formation of new rock types.
The oldest ancient rocks on Earth are found in Western Australia and date back approximately 3.6 billion years.
They provide valuable insights into the planet's early geological history.
A team of geobiologists led by ‘Kurt Konhauser‘ analyzed banded iron formations, a type of rock that stores snapshots of ancient ocean chemistry. The rocks showed a dramatic change in the relative amounts of germanium and silicon about 3.5 billion years ago. This change could have only occurred if rivers were transporting weathered material from land to the ocean.
Water plays a crucial role in this process, as it chips away at rocks on land, removing minerals and washing them away. As ‘Kurt Konhauser‘ explains, ‘As soon as you get weathering, you’ve got a nutrient influx to the oceans, which can lead to… life thriving in coastal waters.‘
The emergence of continents is a subject of debate among scientists, with some studies placing it around 3 billion years ago. However, the new findings push back this timeline by about half a billion years. This change in understanding has significant implications for our knowledge of Earth’s history and the origins of life on our planet.
The presence of continents is essential for life to take hold on their margins. As ‘Eva Stüeken‘, a geochemist at St. Andrews University, notes, ‘It provides a platform for life in shallow water.‘ Most marine life today is located in these shallow marine habitats, and the emergence of continents would have provided the necessary conditions for life to thrive.
The continents are home to a vast array of plant and animal species.
A Africa is known for its savannas and grasslands, which support a wide range of wildlife such as 'lions', elephants, and giraffes.
A South America's Amazon rainforest is the world's largest tropical rainforest, housing over 10% of all known plant and animal species.
A Asia's diverse ecosystems include mangrove forests, coral reefs, and snow-capped mountains.
The continents' unique geography and climate have given rise to distinct biodiversity hotspots.
The team’s findings raise more questions than answers. For example, what was the size of ancient continents? Were they similar in size to those we see today? The team hopes to use their geochemical data to shed light on these mysteries and gain a better understanding of Earth’s history.
- sciencenews.org | Ancient rocks reveal when rivers began pouring nutrients into the sea
