Cambrian Stage 2

Key events in the Cambrian

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Ediacaran

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Ordovician

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Fortunian

"Stage 2"

"Stage 3"

"Stage 4"

"Stage 5"

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Baykonur
glaciation

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Orsten Fauna

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Burgess Shale

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Kaili biota

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Archaeocyatha extinction

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Emu Bay Shale

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Sirius Passet biota

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Chengjiang biota

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First Trilobites

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SSF diversification, first brachiopods & archaeocyatha

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First halkieriids, mollusсs, hyoliths SSF

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Treptichnus pedum trace
Large negative peak δ 13C_carb excursion

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First Cloudina & Namacalathus mineral tubular fossils

Stratigraphic scale of the ICS subdivisions and Precambrian/Cambrian boundary.

Stage 2 of the Cambrian is the unnamed upper stage of the Terreneuvian series. It lies on top of the Fortunian and below Stage 3 of the Cambrian. It is commonly referred to as the Tommotian, after the Cambrian stratigraphy of Siberia.^[1] Both the upper and lower boundary have not been clearly defined yet by the International Commission on Stratigraphy.^[2] Proposals for the lower boundary are the appearance of Small Shelly Fossils, an archaeocyathid species or the mollusc Watsonella crosbyi around ~529 million years ago.^[2] The proposed upper boundary might be the first appearance of trilobites around ~521 million years ago.^[2]

Possible candidates for a GSSP include the first appearance of Watsonella crosbyi in the Zhujiaqing Formation in Yunnan, China or the Pestrotsvet Formation near the Aldan River on the Siberian Platform.^[3]

References

↑ Kouchinsky, Artem; Bengtson, Stefan; Missarzhevsky, Vladimir V.; Pelechaty, Shane; Torssander, Peter; Val'kov, Anatolij K. (24 September 2001). "Carbon isotope stratigraphy and the problem of a pre-Tommotian stage in Siberia". Geological Magazine 138 (4). doi:10.1017/S0016756801005684.
↑ 2.0 2.1 2.2 "GSSP List ICS". ICS. Retrieved 9 November 2012.
↑ Li, Guoxiang; Zhao, Xin; Gubanov, Alexander; Zhu, Maoyan; Na, Lin (1 April 2011). "Early Cambrian Mollusc Watsonella crosbyi: A Potential GSSP Index Fossil for the Base of the Cambrian Stage 2". Acta Geologica Sinica - English Edition 85 (2): 309–319. doi:10.1111/j.1755-6724.2011.00400.x. Retrieved 10 November 2012.

Preceded by Proterozoic Eon	Phanerozoic Eon
	Paleozoic Era						Mesozoic Era			Cenozoic Era
	Cambrian	Ordovician	Silurian	Devonian	Carboniferous	Permian	Triassic	Jurassic	Cretaceous	Paleogene	Neogene	4ry

Geologic history of Earth

Precambrian supereon (4.567 Gya – 541.0 Mya)

eons

eras	periods

Hadean
(4.567–4 Gya)

Paleohadean (4.567–4.3 Gya)

Mesohadean (4.3–4.1 Gya)

Neohadean (4.1–4 Gya)

Archean
(4–2.5 Gya)

Eoarchean (4–3.6 Gya)

Paleoarchean (3.6–3.2 Gya)

Mesoarchean (3.2–2.8 Gya)

Neoarchean (2.8–2.5 Gya)

Proterozoic
(2.5 Gya – 541.0 Mya)

Paleoproterozoic (2.5–1.6 Gya)	Siderian (2.5–2.3 Gya) Rhyacian (2.3–2.05 Gya) Orosirian (2.05–1.8 Gya) Statherian (1.8–1.6 Gya)

Mesoproterozoic (1.6–1 Gya)	Calymmian (1.6–1.4 Gya) Ectasian (1.4–1.2 Gya) Stenian (1.2–1 Gya)

Neoproterozoic (1 Gya – 541.0 Mya)	Tonian (1 Gya – 850 Mya) Cryogenian (850–635 Mya) Ediacaran (635–541.0 Mya)

Mya = millions years ago. Gya = billions years ago.

Phanerozoic eon (541.0 Mya – present)

Paleozoic era (541.0–252.17 Mya)

periods

epochs	ages

Cambrian
(541.0–485.4 Mya)

Terreneuvian (541.0–521 Mya)	Fortunian (541.0–529 Mya) Age 2* (529–521 Mya)

Epoch 2* (521–509 Mya)	Age 3* (521–514 Mya) Age 4* (514–509 Mya)

Epoch 3* (509–497 Mya)	Age 5* (509–504.5 Mya) Drumian (504.5–500.5 Mya) Guzhangian (500.5–497 Mya)

Furongian (497–485.4 Mya)	Paibian (497–494 Mya) Jiangshanian (494–489.5 Mya) Age 10* (489.5–485.4 Mya)

Ordovician
(485.4–443.4 Mya)

Early (485.4–470.0 Mya)	Tremadocian (485.4–477.7 Mya) Floian (477.7–470.0 Mya)

Middle (470.0–458.4 Mya)	Dapingian (470.0–467.3 Mya) Darriwilian (467.3–458.4 Mya)

Late (458.4–443.4 Mya)	Sandbian (458.4–453.0 Mya) Katian (453.0–445.2 Mya) Hirnantian (445.2–443.4 Mya)

Silurian
(443.4–419.2 Mya)

Llandovery (443.4–433.4 Mya)	Rhuddanian (443.4–440.8 Mya) Aeronian (440.8–438.5 Mya) Telychian (438.5–433.4 Mya)

Wenlock (433.4–427.4 Mya)	Sheinwoodian (433.4–430.5 Mya) Homerian (430.5–427.4 Mya)

Ludlow (427.4–423.0 Mya)	Gorstian (427.4–425.6 Mya) Ludfordian (425.6–423.0 Mya)

Pridoli (423.0–419.2 Mya)

Devonian
(419.2–358.9 Mya)

Early (419.2–393.3 Mya)	Lochkovian (419.2–410.8 Mya) Pragian (410.8–407.6 Mya) Emsian (407.6–393.3 Mya)

Middle (393.3–382.7 Mya)	Eifelian (393.3–387.7 Mya) Givetian (387.7–382.7 Mya)

Late (382.7–358.9 Mya)	Frasnian (382.7–372.2 Mya) Famennian (372.2–358.9 Mya)

Carboniferous
(358.9–298.9 Mya)

Mississippian (358.9–323.2 Mya)	Tournaisian (358.9–346.7 Mya) Viséan (346.7–330.9 Mya) Serpukhovian (330.9–323.2 Mya)

Pennsylvanian (323.2–298.9 Mya)	Bashkirian (323.2–315.2 Mya) Moscovian (315.2–307.0 Mya) Kasimovian (307.0–303.7 Mya) Gzhelian (303.7–298.9 Mya)

Permian
(298.9–252.17 Mya)

Cisuralian (298.9–272.3 Mya)	Asselian (298.9–295.0 Mya) Sakmarian (295.0–290.1 Mya) Artinskian (290.1–283.5 Mya) Kungurian (283.5–272.3 Mya)

Guadalupian (272.3–259.8 Mya)	Roadian (272.3–268.8 Mya) Wordian (268.8–265.1 Mya) Capitanian (265.1–259.8 Mya)

Lopingian (259.8–252.17 Mya)	Wuchiapingian (259.8–254.14 Mya) Changhsingian (254.14–252.17 Mya)

Kasimovian and Gzhelian comprise Late Pennsylvanian (307.0–298.9 Mya) subepoch.

Mesozoic era (252.17–66.0 Mya)

periods

epochs	ages

Triassic
(252.17–201.3 Mya)

Early (252.17–247.2 Mya)	Induan (252.17–251.2 Mya) Olenekian (251.2–247.2 Mya)

Middle (247.2–235 Mya)	Anisian (247.2–242 Mya) Ladinian (242–235 Mya)

Late (235–201.3 Mya)	Carnian (235–228 Mya) Norian (228–208.5 Mya) Rhaetian (208.5–201.3 Mya)

Jurassic
(201.3–145.0 Mya)

Early (201.3–174.1 Mya)	Hettangian (201.3–199.3 Mya) Sinemurian (199.3–190.8 Mya) Pliensbachian (190.8–182.7 Mya) Toarcian (182.7–174.1 Mya)

Middle (174.1–163.5 Mya)	Aalenian (174.1–170.3 Mya) Bajocian (170.3–168.3 Mya) Bathonian (168.3–166.1 Mya) Callovian (166.1–163.5 Mya)

Late (163.5–145.0 Mya)	Oxfordian (163.5–157.3 Mya) Kimmeridgian (157.3–152.1 Mya) Tithonian (152.1–145.0 Mya)

Cretaceous
(145.0–66.0 Mya)

Early (145.0–100.5 Mya)	Berriasian (145.0–139.8 Mya) Valanginian (139.8–132.9 Mya) Hauterivian (132.9–129.4 Mya) Barremian (129.4–125.0 Mya) Aptian (125.0–113.0 Mya) Albian (113.0–100.5 Mya)

Late (100.5–66.0 Mya)	Cenomanian (100.5–93.9 Mya) Turonian (93.9–89.8 Mya) Coniacian (89.8–86.3 Mya) Santonian (86.3–83.6 Mya) Campanian (83.6–72.1 Mya) Maastrichtian (72.1–66.0 Mya)

Cenozoic era (66.0 Mya – present)

periods

epochs	ages; italic are chrons

Paleogene
(66.0–23.03 Mya)

Paleocene (66.0–56.0 Mya)	Danian (66.0–61.6 Mya) Selandian (61.6–59.2 Mya) Thanetian (59.2–56.0 Mya)

Eocene (56.0–33.9 Mya)	Ypresian (56.0–47.8 Mya) Lutetian (47.8–41.3 Mya) Bartonian (41.3–38.0 Mya) Priabonian (38.0–33.9 Mya)

Oligocene (33.9–23.03 Mya)	Rupelian (33.9–28.1 Mya) Chattian (28.1–23.03 Mya)

Neogene
(23.03–2.58 Mya)

Miocene (23.03–5.333 Mya)	Aquitanian (23.03–20.44 Mya) Burdigalian (20.44–15.97 Mya) Langhian (15.97–13.82 Mya) Serravallian (13.82–11.62 Mya) Tortonian (11.62–7.246 Mya) Messinian (7.246–5.333 Mya)

Pliocene (5.333–2.58 Mya)	Zanclean (5.333–3.600 Mya) Piacenzian (3.600–2.58 Mya)

Quaternary
(2.58 Mya – present)

Pleistocene (2.58 Mya – 11.7 kya)	Gelasian (2.58–1.80 Mya) Calabrian (1.80 Mya – 781 kya) Middle (Ionian) (781–126 kya) Late (Tarantian) (126–11.7 kya): Oldest Dryas (18–14.67 kya)* Bølling (14.67–14 kya)* Older Dryas (14–13.7 kya)* Allerød (13.7–12.8 kya)* Younger Dryas (12.8–11.7 kya)*

Holocene (11.7 kya – present)	Preboreal (11.7–9 kya)* Boreal (9–8 kya)* Atlantic (8–5 kya)* Subboreal (5–2.5 kya)* Subatlantic (2.5 kya – present)*

Paleogene, Neogene and early Pleistocene comprise former Tertiary* (66.0–1.8 Mya) period. Gelasian and Calabrian comprise Early Pleistocene (2.58 Mya – 781 kya) subepoch.

kya = thousands years ago. Mya = millions years ago. * Not officially recognized by the I.C.S.

Source: International Chronostratigraphic Chart (February 2014). International Commission on Stratigraphy. Retrieved 3 June 2014. Divisions of Geologic Time—Major Chronostratigraphic and Geochronologic Units USGS Retrieved 10 March 2013.