A group of scientists from The Australian National University (ANU) have discovered the oldest colors in the geological record. The pigments they have discovered are 1.1 billion years old and are bright pink. The pigments were extracted from rocks deep under the Sahara Desert in Africa.
ANU’s Dr. Nur Gueneli says that these pigments were taken from marine black shales in the Taoudeni Basin in Mauritania, West Africa. These pigments are more than half a billion years older than the previous pigments that were discovered. Researchers say that these bright pink pigments are molecular fossils of chlorophyll.
That chlorophyll was produced by ancient photosynthetic organisms that inhabited an ancient ocean that vanished eons ago. In concentrated form, the fossils range in color from deep blood red to a deep purple. The bright pink color is seen when the pigments are diluted.
The extraction of the pigments required the billion-year-old rocks to be crushed into a powder. Once crushed the molecules of ancient organisms were extracted. According to the team, these ancient pigments confirmed that cyanobacteria dominated the base of the food chain in the ocean billions of years ago. This helps to explain why animals didn’t exist at that time.
Researchers believe that the emergence of large, active organisms was restrained by the limited supply of larger food particles like algae. While algae is microscopic, it is many thousands of times larger than cyanobacteria making for a much richer food source. Cyanobacterial oceans are believed to have begun to vanish about 650 million years ago.