The Earth's crust, oceans and atmosphere have evolved over an enormous timescale. Geologists (scientists who study the earth) have broken this timescale up into a number of boxes that are usually represented by specific types of rocks or fossils. Names have been given to each of these boxes; and increasingly accurate ages are given to their boundaries.
Some of the boxes are named after places where the rocks were studied in detail (eg the Devonian after Devon). Because the world's surface plates are constantly moving, albeit very slowly, the rocks vary at different times. For example the Devonian sandstones of England represent a time when southern England was in the southern latitudes, near the area occupied by the Namibian deserts today. The Carboniferous rocks in England include coals deposited by vast forests when England lay on the Equator, and the Permian sandstones when we were at the latitude of the western Sahara. During the Jurassic we were crossing the latitude of the Mediterranean and moving north through where Spain is now. During the Cretaceous and Palaeogene we were moving through northern Spain and modern France to our current position. Our northward movement has now slowed right down and we have changed direction - moving eastwards, while North America is moving to the west.
We have included information on this webpage which describes the overall scheme and where the Isle of Wight fits into the global timescale. The time zones have been put into table form so that we can update them as more accurate techniques and data become available.
Some significant events for life have also been added - the times of arrival of whole new groups of organism, and the timing of major extinctions.
The stratigraphic dates below were published in May 2019 by the International Commission on Stratigraphy.
Stratigraphic table and datesEon: Phanerozic - 542 million years to the present
|Jurassic||201.3 +/- 0.2 Ma|
|Triassic||251.902 +/- 0.024 Ma|
|Palaeozoic||Permian||298.9 +/- 0.15 Ma|
|Carboniferous||358.9 +/- 0.4 Ma|
|Devonian||419.2 +/- 3.2 Ma|
|Silurian||443.8 +/- 1.5 Ma|
|Ordovician||485.4 +/- 1.9 Ma|
|Cambrian||541.0 +/- 1.0 Ma|
Eon: Proterozoic - 2500 million years to 542 million years
Eon: Archaen - 4000 million years to 2500 million years
Eon: Hadean (informal) - 4600 million years to 4000 million years
|To be determined||~4600 Ma|
Dates published in May 2019 by the International Commission on Stratigraphy.
(Ma = Mega annum - 'million years' ago).
The Proterozoic and Archaean are sometimes referred together as the 'Precambrian'.
Approximate first appearance of new types of organism
|Organism||Time zone||approx date|
|Flowering plants||Cretaceous||135 Ma|
|Bird-type dinosaurs||Late Jurassic||150 Ma|
|Land vertebrates||Devonian||380 Ma|
|Vertebrates with jaws||Devonian||410 Ma|
|Land plants, Fungi||Silurian||450 Ma|
|Jawless vertebrates||Ordovician||470 Ma|
|Echinoderms (starfish etc), Sponges|
and Coelenterates (jellyfish etc)
|Unicellular animals||Neoproterozoic||700 Ma|
|Organism||Type||Time zone||Approx date|
Last survivor reported 1681
(Wrangel Island, Russian arctic)
|Large mammal||Holocene||6,360 years ago|
|Large mammal||Holocene||10,000 years ago|
|Ammonoids||Marine animal||End Cretaceous||65 Ma|
|Belemnites||Marine animal||End Cretaceous||65 Ma|
|Dinosaurs||Land animal||End Cretaceous||65 Ma|
|Rudist & Trigoniid bivalves||Marine mollusc||End Cretaceous||65 Ma|
|Plesiosaurs||Marine reptile||End Cretaceous||65 Ma|
|Pterosaurs||Flying reptile||End Cretaceous||65 Ma|
|Hybodont sharks||Marine animal||End Cretaceous||65 Ma|
|Ichthyosaurs||'fish lizard' - marine reptile||Upper Cretaceous||95 Ma|
|Placodermia||Armoured fish||End Carboniferous|
|Ancient ferns||Land plant||Upper Carboniferous|
|Graptolites||Marine animal||Upper Carboniferous|
Rocks and fossils of the Isle of Wight
|Era:||Period:||Epoch:||Rock Groups:||Approx age||Typical fossils|
|Palaeogene||Oligocene||Solent||34-31 Ma||Plants, Birds|
|Eocene||Solent||38-34 Ma||Molluscs, mammals|
|Eocene||Thames||54-51 Ma||Shark teeth, molluscs|
|Mesozoic||Cretaceous (K)||Upper K||White Chalk||93.5-68 Ma||Ammonites, belemnites, sea-urchins, shark teeth, sponges|
|Upper K||Grey Chalk||99-93.5 Ma||Ammonites, sea-urchins, sponges|
|Lower K||Upper Greensand||105-99 Ma||Ammonites, sponges, sharks, molluscs|
|Lower K||Lower Greensand||120-||Ammonites, lobsters, oysters|
|Lower K||Wealden||126-120 Ma||Dinosaur bone and footprints!, crocodile, fish, turtle, pterosaur, bivalves, gastropods, ostracods|
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