The origins of life on Earth remain a huge scientific mystery. We know life started simple and small, but just where and under what circumstances did that first spark appear?

Charles Darwin's best guess was that life started in freshwater pools on land on a primeval Earth.

Bubbles preserved in a sticky microbial substance provide new evidence for life living on land around hot springs 3.48 billion years ago. (Tara Djokic)

But over the years, scientists have suggested a more likely scenario was that life started deep in the oceans, around rich, hot hydrothermal vents, like the bubbling "black smokers."

The ocean theory has been supported by good evidence, like fossils found recently in northern Quebec that could be over four billion years old.

Now, new evidence found in remote Western Australia could be tilting the scales back to Darwin's freshwater springs on land idea. These rocks may also have implications for the search for life on Mars.

Joining Quirks & Quarks to tell us more is Tara Djokic, a PhD candidate in geoscience at the University of New South Wales, Australia.