Appendix:Geologic timescale

The eons, eras, periods and epochs of geologic time - most recent first - numbers are millions of years ago and mark the end of the timeframe

66-present

• 2.58-present

• 0.0117-present - end of most recent glaciation; start of civilization

• 2.58-0.0117 - rise and fall of the large mammals, evolution of man

• 0.126-0.0117

• 0.781-0.126

• 1.80-0.781

• 2.58-1.80

• 23.03-2.58

• 5.333-2.58 - ice age, modern mammals and molluscs appear

• 3.600-2.58

• 5.333-3.600

• 23.03-5.333 - moderate climate, mountain building, modern mammals & birds appear, grasslands expand

• 7.246-5.333

• 11.62-7.246

• 13.82-11.62

• 15.97-13.82

• 20.44-15.97

• 23.03-20.44

• 66.0 - 23.03 - Mild change in climate, spread of mammals and birds.

• 23 - warm climate, rapid evolution,

• 34 - archaic mammals, start of current ice age

• 56 - tropical climate, first large mammals

• Reign of reptiles (Dinosaurs)

• 66 - Last dinosaurs

• 100 - break up of Gondwanaland, flowering plants and Bees

• 201.3-145.0 - Peak of reptiles, first birds and true mammals

• 145 - Peak of sauropods

• 161 - lizards, mammals

• 175 - ammonites

• 200 -- archosaurs

• 230 - amphibians, First dinosaurs

• 245 - first small mammals

• 251 - supercontinent of Pangea

• 260 - gymnosperms

• 270 - beetles and flies

• 299 - winged insects

• 306 - reptiles, coal forests

• 312 - high oxygen content atmosphere

• 318 - primitive trees

• 326 - primitive sharks

• 345 - glaciation

• 359 - clubmosses

• 385 - crinoids

• 398 - jawed fish

• 416 - first vascular land plants

• 419 - millipedes

• 423 - corals

• 428 - trilobites

• 443 - invertebrates dominant

• 461 - starfish

• 471 - first land plants

• 541.0±1.0-485.4±1.0

• 497-485.4±1.0

• 489.5-485.4±1.0 - Cambrian explosion of life

• 494-489.5

• 497-494 - Trilobites

• 509-497

• 500.5-497

• 504.5-500.5

• 509-504.5

• 521-509

• 514-509 - sponges

• 521-514

• 541.0±1.0-521

• 529-521

• 541.0±1.0-529

2,500-541.0±1.0

1,000-541.0±1.0

• 635-541.0±1.0 - first multi-celled animals

• 850-635 - snowball earth

• 1,000-850 - acritarch radiation

1,600-1,000

• 1,200-1,000 - formation of Rodinia

• 1,400-1,200

• 1,600-1,400

2,500-1,600

• 1,800-1,600 - first complex single-celled life

• 2,050-1,800 - transition to oxygen atmosphere

• 2,300-2,050

• 2,500-2,300

4,000-2,500

2,800-2,500 - stabilization of most modern cratons

3,200-2,800 - first stromatolites

3,600-3,200 - first known aerobic bacteria

4,000-3,600 - first single-celled organisms

Before 4,000

• ~4,000 - oldest known rock
• 4,400 - oldest known mineral
• 4,570 - Earth formed