Just reading J.P. Mallory's "Origins of Ireland" - Thames and Hudson
It's mainly a human pre-history, but the introductory chapter has a nice outline of how the island came into the shape it is in today.
"The Ireland that we know is a geological accident forged between two continents and then frozen, dunked beneath warm seas, lifted in part to the heights of the Himalyas, covered with lush tropical swamps, blistering deserts and vast expanses of molten rock, then again buried under ice and finally thawed out."
To summarise -
- 10 billion years ago recycled debris from earlier stars coalesced to form 'our' sun and planets
- the superhot Hadean eon lasted over 6 billion years - earth was molten, giving off gases, and cratered by raining meteors
- in the Archaean eon, from 3.8-2.5 billion years ago, things were cooling - 80% of the earth's crust formed and rain began to fall
- 3.5 billion years ago, oceans first covered most of the earth's surface, formed from condensing volcanic water vapour and bacteria, the first life form, came into being
- lighter mineral material rose above the sea bed and some islands - continents - were formed in the Protoerozoic era - 2.5 billion to 250 million years ago
- about 1.7 million years ago, a sandy shore sank, heated and then erupted form what is now part of the island of Inishtrahull, north Donegal, the oldest bit of Ireland
- a billion years ago, all of the landmasses had merged to form a single continent
- 700 million years ago, this supercontinent began to break up - there was a northern section "Laurentia" containing what was to become Canada, Greenland and N. W. Ireland
- to the south separated by ocean was Gondwana, which was to form Africa, India, Antartica, Australia and South America - and also, South East Ireland, Wales and England. Proto-Ireland's nearest neighbouring terrain became West Africa.
- about 560 million years ago, there was another big break up - the two future parts of Ireland shifted apart further on plates over 200 km deep. The rock on which Cork and Belfast sit were 4000 km apart.
- There were millions of years more shifting around, volcanic eruptions, colliding plates, ice sheet cover and laying down of sediment during which time micro organisms photosynthesised gases and thus formed the atmosphere with currently high levels of oxygen
- About 443-417 million years ago (the Silurian period) as the heavy ocean floor materials sank back down into magma the two masses containing the material that was to be Ireland moved together. Continents crashed together. The joining scar is along a line from Dundalk to Limerick (very roughly) and on across the ocean to the USA.
- at this stage, future Ireland was still south of the equator.
-Plants began to grow on our bit of this terrain ('Cooksonia' - 5 cm in height, generating soil cover) and Vinegar Hill and Lambay Island were active volcanoes.
417-354 milion years ago was the Devonian period. Parts of the land pushed up higher than today's Himalyas, rainless and weathering to form more soil and sandstone - more complex life forms were evolving - a lungfish fossil about a metre from this period was found in Valential (future Ireland).
-354 million years ago was the Carboniferous era - sea level rose, and only Wicklow and Donegal poked above the sea - the limestone that forms 2/3rds of Ireland's present rock mantle formed and a split opened up along what is now our western seaboard - what is now North America detached and shifted west. Coals and metals formed.
- In the Permian period 290-248 million years ago most of the planets land masses fused back together again. A mountain range linked the materials that were to form 'Ireland' Brittany and the Czech Republic. Most of the coal in future Ireland was washed away by erosion.
- at the end of the Permian, there was a mass extinction of up to 50% of life in the oceans for reasons as yet unknown.
- the Mesozoic was the era of dinosaurs - Ireland was salty and sandy, on the North West coast of a massive land mass - the US having departed west. (206 million years ago
- In the Cretaceous period, 142 - 65 million years ago, all of what was to be Ireland was under the sea, apart from Carlow. The sea was 28 degrees centigrade.
- an asteroid then hit Mexico, and it is speculated that this abruptly ended dinosaur life.
65 -23 million years ago, in the Paleogene era, 'Ireland' was attached to France, and was quite a bit cooler.
13 million years ago magma from a massive eruption formed the Mourne Mountains
- in the Neogene era water erosion shaped the landscape into something nearer to what we have today in more or less the same position, but not yet an island.
- the Quaternary, 1.6 million years ago to the present, saw the arrival of the Ice Age which we are still in. Temperatures fluctuated, ice melted and extended again, forest developed and were wiped out.
- 80,000 years ago - the Midlandian - still part of a continental mass - Ireland became closer what it is at present. Ice sheets scraping and dumping materials formed eskers and drumlins. At times ice was up to 700 m thick across most of Ireland, but there was a warm period 40,000-20,000 years ago when hare, hyena, woolly mammoth, red deer, iant Irish deer, horse, lemming, fox and geese - followed by 7000 years od ice desert.
A short while after - only a few thousand years, Ireland became an island and humans moved in. I'll save that for another post.
We are of course still on the move.