Earth's youngest banded iron formation found in western China
New Delhi : Scientists have come up with an interesting discovery which states that the banded iron formation, located in western China is as old as Cambrian. Dating back to almost 527 million years old, this formation is young by comparison to the majority of discoveries till date. Experts say that the deposition of banded iron formations began approximately 3.8 billion years ago and had long been thought to conclude before the start of the Cambrian Period at 540 million years ago.
"This is critical, as it is the first observation of a Precambrian-like banded iron formation that is Early Cambrian in age. This offers the most conclusive evidence for the presence of widespread iron-rich conditions at a time, confirming what has recently been suggested from geochemical proxies," said Kurt Konhauser, professor in the Department of Earth and Atmospheric Sciences and co-author. Konhauser administered the research and the study was led by Zhiquan Li, a PhD candidate from Beijing while on exchange at UAlberta.
The period of early Cambrian is known for the rise of animals, so the oxygen level in seawater should have been closer to near modern levels. "This is important as the availability of oxygen has long been thought to be a handbrake on the evolution of complex life, and one that should have been alleviated by the Early Cambrian," says Leslie Robbins, a PhD candidate in Konhauser's lab and a co-author on the paper.
The researchers compared the environmental characteristics and geochemistry to ancient and modern samples to find an analogue for their deposition. The team used rare earth element patterns to reveal that the deposit formed in, or near, a chemocline in a stratified iron-rich basin.
"Future studies will aim to quantify the full extent of these Cambrian banded iron formations in China and whether similar deposits can be found elsewhere," says Kurt Konhauser.