More on the Age of Things

ANDYSEZ  Number 31    (Journal  35, June 1999, pp 41-42)

Well again this is going to be a bit of a pot-boiler although I have had a good idea for next time around - which is going to take a little bit of research! But I need questions from you - what conundrum do YOU want addressed?

This is the first ANDYSEZ post ACKMA Insights - the CD-ROM produced by Peter Bell and Robyn McBeath from CaveWorks at Margaret River - and released at the Mount Gambier Conference. Initially I thought the price a bit steep - but when you get thirty ANDYSEZs, all the conference proceedings and a selection of papers from the Journal it is a real bargain - two bucks an ANDYSEZ! - theft (from ACKMA!). If you look at the purchase price of all of that Peter Costello would be after you to adjust the budget surplus? Look for the scanned stalagmite - it looked good as a photocopy but with a bit of UV light it looks truly fantastic. Which reminds me - back in the early ANDYSEZ days I was going to talk about light - but I can't find the little text that had some wonderful stuff to help us. So it will have to wait.

Last time I talked about the age of our Earth - I thought I would provide a dry list of milestones this time. Many, perhaps most, derived from Hughes (1995) but others from a variety of other scattered sources - including the Canberra Times. Many are open to disputation. Here goes (ages in Ma - millions of years before present):

13000 Age of the Universe - although there has been recent discussion of a much older age than this - but the exact figure is probably of little relevance to ACKMA!1000First sexual reproduction - you were waiting for this, weren't you!
4700 Solar nebula forms 950 First evidence of ice ages
4600 Earth complete770Ice ages
4450 Extensive volcanic activity adds steam and carbon dioxide to the atmosphere. Comets adding water 670 First true animals
4400 Water condenses to form the oceans 650

Mountain building and formation of Gondwana

4276 Oldest rock material known - reworked from older rocks 620 First common worms with tube-like body and primitive nervous system
4000 First life appears - simple bacteria feeding on organic molecules 570 Start of the Cambrian; massive diversification of life forms
3962 Oldest un-reworked rocks - from Greenland 550 Major marine extinctions
3800 Photosynthesis established 510 Start of the Ordovician; first vertebrates
3500 Stromatolites appear 460 Europe collides with North America (or the other way round? And it hasn't stopped!)
3000 Moon solidifies 440 Start of the Silurian; more ice ages and mass extinctions
2800 Formation of the cores of ancient continents 430 Start of long warm period; formation of coral reefs and major limestone deposits
2300 Land grouped together into the first supercontinent 425 First life on land; first jawed fish
2100 The first single celled animals and fungi appear 410 Devonian commences
1800 Free oxygen appears in the Earth's atmosphere 400 First lungfish
1750 Oxygen kills many bacteria - those that survive adapt to using oxygen or live in oxygen-free (anaerobic) environments 395 First arthropods on land - millipedes, mites, spiders, scorpions and springtails
1300 First complex multicellular organism - a seaweed 370 More mass extinctions, especially in the sea. Coral reefs devastated. First amphibians and first forests
  355 Start of Carboniferous - climate cools
(page break in original: seeking volunteers to rearrange the table)
350 Euro-America collides with Gondwana - cultural imperialism! Huge amounts of carbon dioxide converted to limestone - hooray! 37 End of Eocene - temperatures tumble and many marine extinctions but new birds and mammals have appeared slightly earlier
340 First reptiles 24 Grass becomes widespread and grazing animals emerge
330 First winged insects 21 Apes split off from monkeys
300 Start of Permian - climate cools further 16 Global cooling resumes. Widespread herds of grazing mammals
290 Ice ages - south polar ice sheet over much of Gondwana including present day Australia 15 Many extinctions. Sea level falls. Climate oscillates
275 First marine reptiles 14 East Antarctic ice sheet forms
255 Mammal-like reptiles become dominant reptiles on land 10 Maximum activity in formation of the Alps as Italy pushes into Europe - not for the last time!
245 Triassic begins. Major extinctions with over 50% of animal families lost 6.6 West Antarctic ice sheet forms. Sea levels drop 40 m
235 First dinosaurs, flowers and frog-like amphibians 6.3 Mediterranean Sea dries out!
225 First giant herbivorous dinosaurs and winged reptiles 5.3 Mediterranean reformed via huge waterfall between Gibraltar and Africa
220 Supercontinent Pangaea complete 5 Uplift of Himalayas. Apes and "ape-men" divide
216 First mammals 3.5 North and South America join up
210 Pangaea begins to breakup 3.25 Most recent series of ice ages commences
205 Start of Jurassic - warm seas and abundant life 2.4 First stone tools. Ice age intensifies
170 Peak formation of oil 1.9 Homo erectus emerges
150 Archaeopteryx flies. But there are earlier bird-like dinosaurs 1.6 Humans start to use fire
140 Eurasia and North America breaking away from the southern continent 1 Peak of large mammals. Great volcanic activity
135 Start of Cretaceous. Many new dinosaurs 0.73 Asteroid impact near Australia. Many extinctions and the most recent magnetic reversal
0.6 Homo sapiens emerges
125 First modern flowering plants. First marsupial animals which migrate to Australia and Antarctica before the spilt from Africa 0.073 Huge volcano erupts in Indonesia, climate cools further
114 First placental mammals 0.04 Modern man (Homo sapiens sapiens) emerges - from a cave?
100 India breaks away from Antarctica 0.034 Neanderthals are extinct - perhaps?
95 First primate ancestors 0.018 Peak of last ice age
90 Warm, productive seas. Deposition of chalk in Europe and oil in the Middle East 0.014 Thaw starts
85 South America breaks away from Africa 0.010 Brief refreeze
75 Tryannosaurus is dominant carnivore. First primates 0.0006 Aboriginal people arrive in Australia
65 Mass extinctions especially of dinosaurs. Start of the Tertiary 0.00034 Tutankhamun reigns in Egypt
62 Fall in sea levels completes emergence of North America 0.000007 Celery Reckons emerges
60 North America breaks from Europe - not for the last time! 0.000006 Flipper emerges
55 First grasses suitable for grazing. New mammals emerge - whales, elephants and big cats 0.000005 Andysez emerges
50 Australia breaks from Antarctica leaving the latter over the South Pole 0.000004 Age of Aquarius
45 India collides with Eurasia and the Himalayas start to form 0.0000012 Age of ACKMA commences