Great Oxygenation Event - SOLD 5.94" Polished Banded Iron Slab
Great Oxygenation Event - SOLD 5.94" Polished Banded Iron Slab
This specimen is a polished banded iron slab from the Cleaverville Formation in Western Australia. The material formed 3,020,000,000 years ago during the Great Oxygenation Event, a period where cyanobacteria photosynthesized massive amounts of free oxygen, creating the atmosphere we breathe today.
The magnificent polished slab measures 5.94" in length along its longest side. It has been specially prepared to bring out the brilliant reds, yellows, and oranges present in the 3 billion-year-old material. The specimen also comes with a metal stand and an individual certificate of authenticity.
From the far reaches of deep time
3,800,000,000 years ago, oxygen in the Earth's atmosphere was near zero percent. Then, over billions of years, microscopic cyanobacteria began to photosynthesize and generate breathable oxygen bit by bit.
This process is known as the Great Oxygenation Event and it is the reason we have a planet we can live on today. This changed more than just the atmosphere though—the presence of free oxygen also created bands of iron-oxide deposits which serve as physical evidence of the changing planet.
The rich colors found in banded iron formations show the process of oxygenation as it occurred over billions of years. This makes these stones important sources of information for learning about the development of our planet and it came to support complex life.
This specimen is a polished banded iron slab from the Cleaverville Formation in Western Australia. This particular formation dates back 3,020,000,000 years to the Archean Eon and was formed by the oxygen production of cyanobacteria.
The banded iron slabs in our collection are unique in that they have layers of luminescent yellow stone between the red stripes of iron-oxide. They are colloquially known as "tiger iron" thanks to this colorful pattern.
Each specimen is hand polished and exhibits a unique set of colors in a layered pattern. A certificate of authenticity is also included. No two are alike and you can find all available banded iron slabs in the collection below.
Explore billions of years of history in this magnificent geologic wonder!
MORE ABOUT THE GREAT OXYGENATION EVENT
📸 An artist's interpretation of the Earth, billions of years ago
A breath billions of years in the making
The Great Oxygenation Event marks the buildup of oxygen in the Earth's early atmosphere. Reaching a peak 2.3 billion years ago, the evidence of the Great Oxygenation Event is found in banded iron formations found across the planet.
We can chart the accumulation of oxygen in the atmosphere through the colors on these banded iron formations. The striking red, black, and silver lines are composed of thousands of iron oxide layers. Each layer is distinctive and the current leading theory suggests that they are the result of oxygen released in the early acidic seas by photosynthetic cyanobacteria. After more than a billion years, this process resulted in the semi-permanent oxygenation of Earth's oceans.
Even considering the scale of geological deep time, the Great Oxygenation Event was a very long-running process, perhaps spanning more than 2,000,000,000 years. There is also substantial evidence that this process ran in fits and starts in different regions of the world and was influenced by asteroid impacts and massive volcanic eruptions.
📸 A diagram depicting how Banded Iron forms
The Oxygenation Cycle
The earliest Banded Iron Formations date to 3.8 billion years ago when the interior of the planet was still very hot, but the temperature on the iron-rich surface was not much different than it is today. The atmosphere contained little to no oxygen, but there was liquid water on the surface, even enough to form seas... and in those seas there was life.
A blue-green algae, also known as cyanobacteria, lived beneath the surface of the early seas, producing energy from photosynthesis. In turn, their photosynthetic processes created free oxygen which combined with iron carried from the surface into the sea by wind and erosion. The oxygen and the iron combined to form iron-oxides which drifted to the bottom and accumulated in layer after layer.
The formation of iron-oxides neutralized the excess oxygen in the water, allowing the cyanobacteria to thrive, multiply, and evolve. Yet, at times, the population of the cyanobacteria exceeded the balance of iron and the seas became toxic. Such mass extinctions deprived the ocean of oxygen, resulting in new layers of iron-poor silica.
This steady process went on for over a billion years. Then, near the end of the 1.5 billion year Archean Eon, there were several spikes in iron-oxide production which coincided with evidence of rapidly increasing atmospheric oxygen.
Massive plumes rose within the mantle, creating volcanic hot spots and new continents. Sea levels rise alongside new mountains to unprecedented levels. All of this gave life the opportunity to push forward, a "Great Oxygenation Event" which resulted in a permanently oxygenated atmosphere and a chance for life to continue beyond the sea.
From those alternating layers of iron-oxides and iron-poor silica, we find dazzling banded iron formations today. The rich reds and browns are reminders of life in its infancy on Earth and how it was able to change the very planet just through survival.
These iron formations can be found all around the world today. This particular material comes from the Cleaverville Formation in Western Australia and is approximately 3,020,000,000 years old.
Barley, Mark E., Andrey Bekker, and Bryan Krapež. "Late Archean to Early Paleoproterozoic Global Tectonics, Environmental Change and the Rise of Atmospheric Oxygen." Earth and Planetary Science Letters 238.1 (2005): 156-171.
Holland, Heinrich D. "The Oxygenation of the Atmosphere and Oceans." Philosophical Transactions of the Royal Society B: Biological Sciences 361.1470 (2006): 903-915.
Kappler, Andreas, et al. "Deposition of Banded Iron Formations by Anoxygenic Phototrophic Fe (II)-oxidizing bacteria." Geology 33.11 (2005): 865-868.
Luo, Genming, et al. "Rapid Oxygenation of Earth’s Atmosphere 2.33 Billion Years Ago." Science Advances 2.5 (2016): e1600134.