Thrombolites are rock-like formations built by micro-organisms. When these microbes photosynthesize, they precipitate calcium carbonate (limestone), which creates the dome shaped thrombolites. The Lake Clifton,Western Australia, thrombolites are around 2000 years old, 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.
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