Surface-water acidification precedes deep-water carbonate dissolution and anoxia during Oceanic Anoxic Event
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Data di Pubblicazione:
2010
Citazione:
Surface-water acidification precedes deep-water carbonate dissolution and anoxia during Oceanic Anoxic Event / E. Erba, C. Bottini, H. Weissert, C. Keller. ((Intervento presentato al 3. convegno International Paleontological Congress tenutosi a London nel 2010.
Abstract:
The Early Aptian (~120 Ma) Oceanic Anoxic Event (OAE)1a was caused by massive addition of volcanic
CO2 to ocean and atmosphere that should have lowered seawater pH. Calcareous nannofossils trace early
acidification of surface-water in Tethys and Pacific Oceans. The demise of heavily calcified nannoconids
and reduced calcite paleofluxes marks the beginning of the pre-OAE1a calcification crisis, while ephemeral
coccolith dwarfism and malformation represent remarkable species-specific adjustments to survive
maximum acidity. Abundance peaks of peculiar nannoliths trace intermittent alkalinity recovery. Deepwater
acidification occurs with a delay of 25-30kyr. Onset of OAE1a is preceded by a dissolution event
recording 1 to 2km shallowing of the CCD not related to anoxia. After dissolution climax, nannoplankton
and carbonate recovery developed over ~160 kyr, under persisting global dysoxia-anoxia.
Tipologia IRIS:
14 - Intervento a convegno non pubblicato
Keywords:
Aptian, coccoliths, dwarfism
Elenco autori:
E. Erba, C. Bottini, H. Weissert, C. Keller
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