Take me back to Life On Perth!

The Lake Clifton thrombolites are sometimes referred to as the stepping stones of life. Unfortunately some people thought they were just stepping stones, and a special boardwalk had to be built to protect them.

 When Thrombolites Ruled The World.
When Thrombolites Ruled The World.

With their conservation now under control, the thrombolites present an opportunity to view life as it appeared during the Archaean eon of the Earth’s history.  The Archaean happened between 3.8 and 2.5 billion years ago, meaning the Lake Clifton thrombolites provide a unique window into our distant past.  Our thrombolites are only a measly 2000 years old, but they are directly descended from the earliest known life forms on Earth.  They once dominated the shallow Archaean seas, though today only survive in a handful of Earth’s special places.

Bob and Tiffany!

It has a lot to do with the southern hemisphere’s largest community of lake dwelling thrombolites.  The reef stretches an amazing 15 kilometres along the shoreline.  However during 2009, the thrombolites were Lake Clifton’s second biggest attraction.  Local residents, Bob and Tiffany Herdsman, became Australia’s all-time favourite winners of, “The Biggest Loser” game show. They both shed the big kilos, and inspired a nation.  Rumour has it, even the thrombolites didn’t grow their regulation 0.1 mm that year.

Thrombolites - Lake Clifton's Biggest Losers in 2009!

Thrombolites are rock-like formations built by micro-organisms.   When these microbes photosynthesize, they precipitate calcium carbonate (limestone), which creates the dome shaped thrombolites, we see on the edge of Lake Clifton today.  The thrombolites are dominant on the east side of the lake, because their calcium source is in the fresh   groundwater which passes through the sand dunes on this side.  Thrombolites form in shallow water, because the microbes need sunlight to photosynthesize.  The Lake Clifton thrombolites also prefer water with a low salt content.  Lake Clifton is a brackish coastal body of water which has been historically hyposaline.  This means it is normally less salty than seawater, and is ideal for a thrombolite community.

Thrombolites on the shore at Lake Clifton.
  Thrombolites at Lake Clifton.
Thrombolite Reef.

Thrombolites are a type of microbialite.  This a general term used to describe structures formed by microbial communities.  The micro-organisms which are creating the Lake Clifton thrombolites are descendants of the earliest forms of life on Earth.   Life probably first appeared on Earth around 4 billion years ago.  No fossils have survived from these early times, so no one is sure how it all started.  The earliest fossils are of mineralised mounds formed by microbes around 3.5 billion years ago.  These fossils are located in the north of Western Australia, and were formed during the Archaean.   They are known as stromatolites, and are very closely related to thrombolites.  They differ mainly in the way in which they form.  Stromatolites form in layers that are built up on top of each other.  Thrombolites form by a clotting process, and spread out unevenly over time. 

The Edge of the Thrombolite Reef:  The white foam was created by a strong wind blowing across the surface of Lake Clifton.  The foam gets trapped between the thrombolites, and enhances the prehistoric experience.

The Hyundai Motor Corporation would not be the huge car manufacturer it is today without the help of Western Australian thrombolites.  Way back during the Archaean, thrombolites, and their close relatives stromatolites, were the dominant life forms on Earth.  They were the catalyst in a series of events, which billions of years later produced Hyundai motor cars.   To understand this process we must first consider what life was like when thrombolites ruled the world.

  If you had visited the Earth during the Archaean, you would have witnessed a landscape covered with active volcanoes.  The sky would have appeared an uneasy orange colour.  This was due to the high concentration of methane in the atmosphere.  Oxygen was only a trace gas (1%).  The shallow Archaean oceans covered much of the planet, and would have had a slight green tinge.   This was caused by high levels of dissolved iron.  The shoreline would have been covered in thrombolites, and stromatolites as far as your eye could see.  Due to their abundance in the Archaean, you would have been excused for using them as stepping stones.  The moon was much closer to the Earth than today, causing extreme tidal patterns across the planet.  Even the sun was cooler, though because of all the volcanic activity, the climate was rather temperate. 

Fortunately for us, oxygen was released by these microbialites during their photosynthetic metabolism.   Check out the thrombolites on a calm day, and you can still see tiny strings of oxygen rising to the water’s surface.  Archaean oceans contained high concentrations of dissolved iron, released from the Earth’s interior. The microbialite oxygen, oxidised the iron in the oceans to form oxidised iron.  This precipitated as iron oxide, and created the banded iron deposits we mine today.  The extensive Pilbara iron ore deposits in Western Australia, are now shipped to South Korea, and are used by Hyundai to produce their motor cars. 


Admittedly it has been simplified quite a bit, but it should still work well for most models in the current line-up.

But wait...... there is more!

Eventually all of the dissolved iron was oxidised.  This occurred around 1.8 billion years ago, and no more banded iron deposits were created.  The oxygen then escaped into the atmosphere, until it formed
about 21% of the atmospheric gases. 

The oxygenated atmosphere was now ready to kick start the explosion of life on Earth!

Before the Lake Clifton thrombolites were properly understood, some early settlers mistook the microbialite reef for a secret bunyip nesting ground.  Fortunately the eggs never hatched, and the lake has remained bunyip free.  Still not satisfied, the bunyip supporters suggested they were the fossilized eggs of ancient bunyips, which had lived on the shoreline thousands of years ago.

The thrombolites have been more recently associated with extraterrestrial egg pods. They do bear a striking resemblance to those nasty egg sacs seen in the Alien movies.  Whether they’re bunyips, or aliens, just be sure to lock your car, and keep to the designated pathways………because in Lake Clifton no one can hear you scream.

In Lake Clifton no one can hear you at all!

Always visit the thrombolites with a friend.

By 500 million years ago, the most dominant life form on Earth was conspicuously absent.  After creating our iron ore deposits, and oxygenating the atmosphere, they disappeared.  Plate tectonics, and the competition for space, took their toll on the primitive thrombolites.  They were eventually a casualty of their own success. Newly evolving organisms were thriving in the improved conditions, and found the thrombolites to be a very tasty meal.  They were slowly eaten off the face of the Earth.

LOCATION: Lake Clifton is about 115km south of Perth.  Stay on the special boardwalk to avoid damaging the ancient thrombolites.  They have feelings too.
Copyright © 2014 LifeOnPerth.com