Astrobiology researchers are searching for clues to how life evolved on Earth by studying geological forms in the Pilbara region of Western Australia.

"Astrobiology is a huge field. It has many aspects, looking for life out among the stars, probably more simplistic than intelligent life," PhD student Georgia Soares said.

"We look at life but we only have one example, which is back here on Earth.

"So we look at how it evolved through history and then see how that can be replicated in the stars and planets like Mars."

Ms Soares is studying the geological forms that exist alongside ancient stromatolites in the hills of the Pilbara region near Newman, WA.

Two small stromatolites (stripey objects) surrounded by sediment filled with siliceous structures. ( Supplied: Martin Van Kranendonk )

Working on her doctorate alongside other scientists from the Centre for Astrobiology at the University of New South Wales, she looks closely at archaea, bacteria and silica forms that have the possibility of being an early branch of life on Earth before oxygen.

Some methanogens in the form of bacteria and archaea are associated with ancient cyanobacteria in stromatolites that appear in the remote Pilbara rocks.

Around 2.4 billion years ago the Earth experienced a surprising 'global pollution event', surprising because the pollutant was oxygen.

A blue stromatolite in tan sediment. ( Supplied: Erica Barlow )

While oxygen is essential for us nowadays, when it finally accumulated as a gas in the earth's atmosphere it was a poison to many of the life forms.

Early life had to adapt to new conditions as oxygen became part of the atmosphere.

Anything that could adapt to the new world of oxygen became evolutionarily successful, using oxygen to grow and live after planet earth experienced the "global pollution event" of oxygenation.

The stromatolites are the dark, elongated shapes within the lighter sediment. ( Supplied: Martin Van Kranendonk )

Stromatolites of Shark Bay

You can still see stromatolites in the shallow waters of Shark Bay today, but ancient geological forms also exist in the fossil-filled hillsides of the Hamersley Ranges near Karijini National Park.

"There are groups of microbes which live on the shallow sea floor and they get their energy from sunlight and they often get covered by sediment," Ms Soares said.

"So they grow through the sediment to see the sunlight.

"This forms layers and these layers come in the shapes of domes and columns and little cones, and eventually this builds up a great big reef."

Stromatolites exist in Shark Bay as well as in the Hamersley Ranges. ( Supplied: Erica Barlow )

For Ms Soares, the work of astrobiology is to go out and map the stromatolites, looking for evidence of how they grew and what environmental conditions existed in their lifetime.

Her team looks at questions such as, "Did they grow in an oxygenated environment? Did they evolve to adapt to oxygen? Did they become extinct because of oxygen?"

After lab analysis, the data can be compared to what is known of the history of other planets such as Mars.

Working in 40 degree heat of the Pilbara

Ms Soares spent part of the dry season wandering the rocky outcrops in search of samples to study back in the lab.

"It's 40 degrees, boiling hot in the mid-morning, standing out enjoying the nice breeze and looking out across the landscape, unbelievably beautiful country," she said.

"I'm looking at the red sand and all the hills and rocks and thinking, what could be out there? What opportunities are there for exploration of life back 2.4 billion years ago?"

Ms Soares is enjoying the beautiful country in the Pilbara. ( Supplied: Georgia Soares )

Her first experience of the heat and harsh conditions came in her undergraduate Honours year.

"That was the first time I'd ever been to the Pilbara and the first time I'd properly experienced a dry outback Australia," she said.

"It was July when we went and it was super dry, completely different from everything I'd ever seen before in my life. It was just amazing."

Stromatolites featuring bluish, stripey shapes with tops of red silica, separated by fine tan sediment. ( Supplied: Martin Van Kranendonk )

Looking to find life forms on our ancient planet before life as we know it is exciting for a young student.

"We're working in a section of Earth's history that's just a bit younger than the huge banded iron formations of Karijini National Park," she said.

"[They] were laid down when free oxygen was just starting to accumulate in the atmosphere as the product of a micro metabolism, just like cyanobacteria today."

The ridgeline being explored for ancient stromatolites in the Hamersley Ranges. ( Supplied: Georgia Soares )

Methods she and her fellow colleagues use include getting core samples of the structures, dissolving them out of the rock, then looking at them under a 3D microscope.

She looks at the micro-structures, then the bigger structures to work out the morphology on the inside and outside.

Isotope analysis of the mineral grains in the structures and other detailed chemical investigations will be done down the track during her three-year PhD scholarship.

"My PhD is pretty much to figure out whether these things were alive and whether they were a different type of life from what we know," she said