Cambrian Series 3

Key events in the Cambrian

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-550 —

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-540 —

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-530 —

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-520 —

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-510 —

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-500 —

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-490 —

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Ediacaran

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Ordovician

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2

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3

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Fortunian

"Stage 2"

"Stage 3"

"Stage 4"

"Stage 5"

Drumian

Guzhangian

Paibian

Jiangshanian

"Stage 10"

 

 

 

 

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Baykonur
glaciation

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.

Cambrian Series 3 is the still unnamed 3rd Series of the Cambrian. It lasted from about ~509 to ~497 million years ago and is divided into 3 stages: the unnamed Stage 5, the Drumian, and the Guzhangian. Cambrian Series 3 is preceded by also unnamed Cambrian Series 2 and succeeded by the Furongian series.

Naming

The International Commission on Stratigraphy still has to decide on the official name of the 2nd series of the Cambrian. The new name will also replace the older term "Middle Cambrian".

Definition

The lower boundary of Series 3 has the same definition as Cambrian Stage 5. This boundary has not been formally defined yet by the ICS but a number of proposals for fossils and type sections have been made. The most promising fossil markers are the respective first appearances of either trilobite species Ovatoryctocara granulata or Oryctocephalus indicus. Either species should have an age close to ~509. The Series 3-Furongian boundary has the same definition as the Paibian stage. It is defined as the first appearance of Glyptagnostus reticulatus around ~497 million years ago.

Subdivision

Cambrian Series 3 is subdivided into the following stages:

Epoch	Stage	Age (mya)
Furongian
	Stage 10	~489.5
	Jiangshanian	~494
	Paibian	~497
Series 3
	Guzhangian	~500.5
	Drumian	~504.5
	Stage 5	~509
Series 2
	Stage 4	~514
	Stage 3	~521