The human secrets in the sands of time.

About 100,000 years ago, modern humans (Homo sapiens) travelled out of Africa and successfully dispersed to all corners of the globe. Using the very latest techniques, Flinders geoarchaeologist Mike Morley studies the sediments preserved in ancient landscapes to understand when, where and how our ancestors lived, thrived and survived. 

Despite what lost civilisation movies would have you believe, most archaeological sites do not host obvious signs of human habitation.

Clues about past lives are often incredibly subtle. Charcoal from fireplaces, tiny fragments of bone and tools, and even DNA from bodies can survive many thousands of years buried in the landscapes where humans and their relatives once lived. These remnants are only recoverable with the right techniques.

Associate Professor Mike Morley is a specialist in revealing the hidden histories of landscapes. With expertise in geoarchaeology – where geology and geography meet archaeology – he studies how landscapes formed and changed over time and reveals traces of ancient humans and their lives in the sediments buried beneath our feet. 

“Simply put, our work aims to understand human adaptation to different environments across time,” he says. “To do that, we study sediments – a common factor across all archaeological sites.”

Sediment includes everything – dirt, rocks, plant remnants and degraded signs of life – that is deposited across landscapes by gravity, wind and water.

“The laying down of sediments locks crucial information into place about a site’s history,” he says. “We extract whole blocks of intact sediment from field sites in Africa, Europe, Asia and Australia, take them back to our Microarchaeology Laboratory, preserve them and study them.”

Some of this sediment block is soaked hard in resin and turned into microscope slides. It’s an approach termed micromorphology, the archaeological equivalent of cutting pieces from a decorated layer cake and storing them in perpetuity with the ingredients, layers and inclusions all locked exactly in place.

“By looking at slices of the sediment block at varying degrees of magnification, we can work out how the site formed, how it was preserved and degraded, and examine any signs of human occupation,” says Associate Professor Morley.  

His work on sediments has contributed to globally renowned research describing discovery sites of extinct human-like species such as the Denisovans in Siberia and Homo floresiensis (dubbed 'the hobbit') in Flores, Indonesia.  

An exciting future beckons for microarchaeology, as Associate Professor Morley’s recently published work with colleagues from the Max Planck Institute in Germany revealed that blocks of preserved sediment also lock in biological molecules that can be extracted and studied in the laboratory.

“We’ve shown fragments of DNA from humans or closely related species such as Neanderthals and Denisovans can be identified in our preserved sediment blocks – a finding that is potentially a game-changer,” he says. “Now we can go back and study existing sediment blocks from a range of sites, which could open up a whole new body of evidence about where humans and their ancestors lived.”