Mesoarchaean facts for kids
The Mesoarchaean (pronounced Mez-oh-ARK-ee-an) is a very old time period in Earth's history. It's like a chapter in our planet's story, part of the larger Archaean eon. This era started about 3.2 billion years ago and ended 2.8 billion years ago. To give you an idea, that's a really, really long time before dinosaurs even existed! Before the Mesoarchaean was the Palaeoarchaean era, and after it came the Neoarchaean.
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Life in the Mesoarchaean Era
During the Mesoarchaean, life on Earth was still very simple. The most important living things were tiny microorganisms.
Stromatolites: Ancient Life Forms
Fossils found in Australia show that stromatolites were living on Earth during the Mesoarchaean. Stromatolites are layered structures created by tiny living things called cyanobacteria, also known as blue-green algae. These bacteria were some of the first organisms to perform photosynthesis. This means they used sunlight to make their own food, just like plants do today.
- Stromatolites grew in shallow waters.
- They helped to change Earth's early atmosphere.
- They released oxygen as a waste product.
- Over millions of years, this oxygen built up in the air.
Earth's Changing Surface
The Mesoarchaean was a time when Earth's landmasses were moving and changing. Our planet didn't look anything like it does today.
Supercontinents Forming and Breaking Up
A supercontinent is a very large landmass made up of most or all of Earth's continents joined together. During the Mesoarchaean, supercontinents were forming and breaking apart.
- The first supercontinent, called Vaalbara, broke up during this era. This happened around 3.2 billion years ago.
- Another supercontinent, named Ur, existed during the Mesoarchaean. It formed about 3.1 billion years ago. Ur was not as big as some later supercontinents, but it was still a huge landmass for its time.
The Pongola Glaciation
Around 2.9 billion years ago, a major ice age happened. This event is known as the Pongola glaciation. A glaciation is a period when large parts of Earth's surface are covered by ice sheets and glaciers. This shows that even billions of years ago, Earth's climate could change dramatically, leading to very cold periods.
| Precambrian (4.567 gya – 541 mya) | |
|---|---|
| In the left column are Eons, bold are Eras, not bold are Periods. gya = billion years ago, mya = million years ago | |
| Hadean (4.567 gya – 4 gya) | Chaotian Zirconian |
| Archaean (4 gya – 2.5 gya) | Eoarchaean (4 gya – 3.6 gya)
Palaeoarchaean (3.6 gya – 3.2 gya) Mesoarchaean (3.2 gya – 2.8 gya) |
| Proterozoic (2.5 gya – 541 mya) | Palaeoproterozoic (2.5 gya – 1.6 gya) Siderian (2.5 gya – 2.3 gya) Rhyacian (2.3 gya – 2.05 gya) Orosirian (2.05 gya – 1.8 gya) Statherian (1.8 gya – 1.6 gya)
Mesoproterozoic (1.6 gya – 1 gya) Calymmian (1.6 gya – 1.4 gya) Ectasian (1.4 gya – 1.2 gya) Stenian (1.2 gya – 1 gya) Neoproterozoic (1 gya - 541 mya) Tonian (1 gya – 720 mya) Cryogenian (720 mya – 635 mya) Ediacaran (635 mya – 541 mya) |
See also
In Spanish: Era Mesoarcaica para niños
