What is the Tonian period?

Tonian (Greek: "Stretch") is the first geological period of the last billion years, which is 1,000 million over 850 million years ago. Tonian is the first period of a longer neoproterozoic era, which also includes cryogenic and Ediacaran. Unlike the many geological periods that come after it, Tonian is not defined on the basis of rock layers (stratigraphy), but radiometric dating. The average temperature can be 10 ° C (41 ° F) cooler than today, especially in continental interiors. Possible trace fossils of small methazoan, such as 1 mm worms -like worms, were found danians dating and even 200 million years before, in the Senian period. Although no body cast of fossils of animals come to tonians, it may be because the organisms were very small, soft and fossilized. The Tonians were obtained by multi -cellors from fossils.

In addition to unicellular mushrooms, bacteria, archaeans and several multicellular algae and possible primitive metazoans in the Tonian period there was no life.These primitive organisms probably inhabited soil immediately around water sources. In general, oxygen levels were lower in Tonians than during the subsequent cryogenic and edicaran, making the development of complex life more difficult. Microbes gathered into large thick colonies called microbial mats. These microbial mats have no modern analogs, because any exposed mats would quickly absorb animals.

The most common Tonian fossils are acrimp, mostly the remains of planktonic algae and other unknown, but related organisms. Acritarchy appears in a fossil record more than 1400 million years ago, blooming diversity over the next 600 million years. About 800 million years ago, shortly after Tonian, Glacial Event Sturtian-Maranger Glass Event, covering the planet in the ice layer and sharply limiting the diversity of Acritarch. Before the planet started warming upAt 630 million years ago, the first complex multicellular organisms began to appear.