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Lime mud records Toarcian ocean acidification
Micrite boron isotopes from Spain and Portugal show a transient pH drop at the Toarcian Oceanic Anoxic Event that brachiopod shells miss.
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Which carbonate archive recorded Toarcian acidification?
Micrite (lime mud) boron isotopes, not brachiopod or oyster shells.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
How large was the micrite δ11B drop at the CIE?
A transient decrease of 4 to 6‰.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
What did brachiopod δ11B do through the T-OAE?
Remained relatively stable around +13.7‰ in Spain and +14.1‰ in Portugal.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
What volcanic provinces are linked to the T-OAE?
Karoo and especially Ferrar large igneous provinces.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
Where were the two sections?
Barranco de la Cañada (Spain, Iberian Basin) and Rabaçal/Fonte Coberta (Portugal, Lusitanian Basin).
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
What modelled pH did the global ocean reach?
Just above 7.4.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
Did community recovery require pH rebound?
No; recovery in Spain tracked cooling while pH stayed low.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
Why is micrite useful despite lacking a pH calibration?
It still captures relative trends in ocean pH.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
What chemostratigraphic duration is assigned to the T-OAE here?
About 500,000 years from CIE onset through δ13C recovery.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
Which opportunistic brachiopod dominated the stressed fauna?
Soaresirhynchia bouchardi.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified
What greenhouse-gas rise accompanied the event?
Atmospheric CO2 from ~260 ppm up to 1000 or even 1800 ppm.
Source: Ocean acidification at the Toarcian Anoxic Event captured by boron isotopes in the lime mud record · DOI · quote verified