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Geological Periods
Depending on the Earth's rocks, the history of Earth is divided in periods
| EON |
PERIOD |
ERA |
MILL. YEARS AGO |
|
| Cenozoic |
Quaternary |
Holocene |
0,01 |
Many mammals are dying of alternating glacial periods. The North and South America is joined. The vertebrates are evolving rapidly as the environment changes periodically. The modern man Appears (Homo sapiens).
|
| Pleistocene |
1,6 |
| Neogene |
Pliocene |
6,3 |
Appearance of the large mammals and the evolution of birds. The primates are evolving and the meadows are expanding. The Himalayas and the Grand Canyon is formed. The continents are starting to take its current shape.
|
| Miocene |
23 |
| Paleogene |
Oligocene |
36,6 |
| Eocene |
53 |
| Paleocene |
66 |
| Mesozoic |
Cretaceous |
135 |
Flowering plants proliferate as well as the first small terrestrial mammals. Dinosaurs disappear. Formed deposits of oil and natural gas. |
| Jurassic |
205 |
Dinosaurs abound. The Archaeopteryx, the oldest known bird evolved from reptiles. The Pangea dismembered. |
| Triassic |
250 |
Mammals appear. Seeded plants prevail. North America and Europe are tropical countries. |
| Paleozoic |
Permian |
290 |
Conifers replace the ferns. Reptiles are multiplied. Deserts are expanding. |
| Carboniferous |
355 |
Vast marshy forests grow in estuaries. From these forests formed the coal reserves. Amphibians abound. The first reptiles evolved from amphibians. The glacial period in Gondwana. |
| Devonian |
410 |
Sharks and many other species abound in the seas. The first insects and amphibians, such as Ichthyostegos, make their appearance. The first forests are formed from seeded plants and consist of giant ferns and mosses. The first sandstone appears in the deserts. |
| Silurian |
438 |
First Vascular plants, first millipedes and arthropleurids on land. First jawed fishes, as well as many armoured jawless fish, populate the seas. Fish also occur in lakes and rivers. The continents move and begin to approach each other. |
| Ordovician |
510 |
Crustaceans appear along with the first fish-like vertebrates. Coral reefs begin to form in the oceans, while the southern continents are shifting towards the poles. A glacial period in the Sahara. |
| Cambrian |
570 |
There is no terrestrial life. A variety of algae and invertebrates thrive in the oceans. Articulated mollusks appear, such as the trilobites. |
| Precambrian |
4.600-570 |
We have the formation of Earth, the first sedimentary rocks, anaerobic bacteria and microscopic algae. Only a few fossil records exist from this period, but we know that the first unicellular organisms appeared such as cyanophytes. Later multicellular organisms with soft parts appeared, such as jellyfish and worms.
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Mapping of the Eons with 24-hour
To understand when man was created and the various periods and Eons were created, we will make a match. Specifically, the 4.6 billion years of Earth will be matched in 24 hours. So if our clock shows 24.00 exactly, then the Eons appeard and finished some minutes ago:
APPEARANCE OF EON
|
BEFORE
in minuites
|
BEFORE
million years
|
FACTS
|
| |
FROM |
TO |
FROM |
TO |
|
| Cenozoic |
20,2 min |
Today |
64,5 |
Now |
The Modern extinction of species |
| Mesozoic |
77 min |
20,2 min |
245 |
64,5 |
65 million years before the Cretaceous Extinction (Dinosaurs, etc.) |
| Paleozoic |
170,3 |
76,7 |
544 |
245 |
245 million years before the Permian extinction |
| Neoproterozoic |
281,7 |
170,3 |
900 |
544 |
|
| Mesoproterozoic |
500,9 |
281,7 |
1.600 |
900 |
|
| Paleoproterozoic |
782,6 |
500,9 |
2500 |
1.600 |
|
| Αρχαιοζωικός |
1.190 |
782 |
3800 |
2500 |
|
| Καταρχαιοζωικός |
1.440 |
1.190 |
4600 |
3800 |
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- The recorded history of mankind exists in the last 2.5 seconds, or the last 10,000 years.
- The first Homo sapiens appeared 37 seconds ago or 2,000,000 years ago.
- The Cenozoic Age started before 20.2 minutes or 64.5 million years ago.
- The Cretaceous Period - that eventually became the Great Extinction - started 45.7 ago and ended 20.2 minutes ago or started 146 million years ago and ended 64.5 million years ago.
- The Jurassic Period - which was dominated by dinosaurs - started 65 minutes ago and ended 45.7 minutes ago or started 208 million years ago and ended 146 million years ago.
- The first fish appeared when the clock showed 21:22 and the dinosaurs showed at 22:50.
- None of these animals would appear until the Earth was a favorable habitat for life.
Who gives the names of geological periods?
The International Commission on Stratigraphy, part of the International Union of Geological Sciences, undertakes to give the names of the various geological periods and centuries.
Recently, they named the period that began 600 million years ago and ended 542 million years ago, Ediacaran. The new name comes from the Ediacara hills in Flinders Range of South Australia, where they found perfectly preserved marine molluscs, from an era 550 million years ago. This period is between the Cryogenic (when the Earth was pretty much a snowball) and the Cambrian, when it took off really complex forms of life. And experts took approximately 15 years to get this decision.
The scientists, who began the study of geology two centuries ago, gave their names to the layers studied. For example, the Devonian Period took its name in honour of Devon, the Cambrian from the Roman name for Wales (Cambria), the Permian and Jurassic from Russia and the Alps, respectively.
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