End-Botomian mass extinction

Botomian

Marine extinction intensity during Phanerozoic

%

Millions of years ago

(H)

K–Pg

Tr–J

P–Tr

Cap

Late D

O–S

Apparent extinction intensity, i.e. the fraction of

Holocene extinction event

)

The end-Botomian mass extinction event, also known as the late early Cambrian extinctions, refer to two extinction intervals that occurred during Stages 4 and 5 of the

There are several hypotheses for the causes of these extinctions. There is evidence that major changes in the carbon cycle^[6][7][8][9] and sea level occurred during this time.^[1][10] Evidence also exists for the development of anoxia (a loss of oxygen) in some environments in the oceans.^[1][11][12]

One hypothesis that unifies this evidence links these environmental changes to widespread volcanic eruptions caused by the emplacement of the Kalkarindji Large Igneous Province or LIP.^[13][14] These widespread eruptions would have injected large amounts of greenhouse gases into the atmosphere causing warming of the climate and subsequent acidification and loss of oxygen in the oceans.^[13] Mercury anomalies have been discovered in strata corresponding to the extinction event; however, such enrichments in mercury are also found in older rocks that predate the biotic crisis.^[15] The precise timing between the eruptions and the extinction events remain unresolved.^[14]

References