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PHANEROZOIC and

Age / /Age Age Series/Epoch Stage/Age Age / /Period Era Era Eon Eon Eon Ma Period Period System System Erathem Erathem Eonothem Eonothem 252.2 ±0.5 541 0.0118 254.2 ±0.3 Neo- 635 Upper 0.126 259.8 ±0.4 850 “Ionian” 0.781 265.1 ±0.4 1000

Quaternary 268.8 ±0.5 1.806 Meso- 1200 2.588 272.3 ±0.5 proterozoic 1400 3.600 279.3 ±0.6 1600 5.333 290.1 ±0.2 Proterozoic 1800 Paleo- 7.246 295.5 ±0.4 2050 proterozoic 11.63 298.9 ±0.2 2300 13.82 Upper 303.7 ±0.1 2500 a l e o z i c P 15.97 307.0 ±0.2

Burdigalian Penn- Middle Moscovian

20.44 sylvanian 315.2 ±0.2 2800 Lower 23.03 323.2 ±0.4 r e c a m b i n P

C e n o z i c Upper 28.1 330.9 ±0.3 3200 Middle Visean 33.9 346.7 ±0.4 Missis- sippian Lower 37.8 ±0.5 358.9 ±0.4 3600 41.2 ±0.5 Upper 372.2 ±1.6 47.8 ±0.2 382.7 ±1.6 4000

56.0 h a n e r o z i c P

Paleogene Middle 387.7 ±0.8 (informal) 59.2 393.3 ±1.2 ~4560 61.6 407.6 ±2.6 Units of the international chrono- Lower 66.0 ±0.05 410.8 ±2.8 stratigraphic scale with estimated 72.1 ±0.2 419.2 ±3.2 numerical ages from the GTS2012 Pridoli age model. 83.6 ±0.2 423.0 ±2.3 Colors are according to the Upper 86.3 ±0.5 Ludlow 425.6 ±0.9 Commission for the Geological Map 89.8 ±0.3 427.4 ±0.5 of the World. 93.9 ±0.2 Wenlock 430.5 ±0.7 Subdivisions of the are 100.5 ±0.4 formally defined by a Global boundary 433.4 ±0.8 Stratotype Section and Point (GSSP) at

P h a n e r o z i c P 113.0 ±0.4 438.5 ±1.1 Llandovery each lower boundary. Thick yellow lines 126.3 ±0.4 440.8 ±1.2 Barremian between stages on this diagram denote Lower 130.8 ±0.5 443.8 ±1.5 GSSPs approved by the International 133.9 ±0.6 445.2 ±1.4 Commission on Stratigraphy (ICS) and Upper 139.4 ±0.7 453.0 ±0.7 ratified by the International Union 145.0 ±0.8 of Geological Sciences (IUGS). 458.4 ±0.9 Precambrian units are formally defined 152.1 ±0.9 Middle 467.3 ±1.1 Upper by absolute age (Global Standard 157.3±1.0

Ordovician 470.0 ±1.4 Stratigraphic Age — GSSA), with the 163.5 ±1.1 Lower 477.7 ±1.4 exception of the Ediacaran System 166.1 ±1.2 485.4 ±1.9 defined by a basal GSSP. Stage 10 Middle 168.3 ±1.3 ~ 489.5 Numerical ages assigned to unit M e s o z i c boundaries are subject to revision upon 170.3 ±1.4 ~ 494 formal decision or revision of GSSPs 174.1 ±1.0 ~ 497 and when enhanced radio-isotopic and 182.7 ±0.7 ~ 500.5 cyclostratigraphy studies enable Series 3 Lower 190.8 ±1.0 ~ 504.5 improvements to the age models. Stage 5 199.3 ±0.3 ~ 509 Stratigraphic information and details

Hettangian Stage 4 on international and regional geologic 201.3 ±0.2 Series 2 ~ 514 Stage 3 units can be found on the websites of ~ 209.5 ~ 521 Upper Stage 2 the ICS (www.stratigraphy.org) and the ~ 228.4 ~ 529 Geologic TimeScale Foundation 237.0±1.0 541.0 ±1.0 (https://engineering.purdue.edu/stratigraphy). This chart was drafted by Gabi Ogg. Middle 241.5 ±1.0

Triassic 247.1±0.2 Lower 250.0±0.5 Copyright © 2012 Geologic Scale Foundation 252.2 ±0.5