Availability of nutrients in the ocean can be a major factor affecting bioproductivity, burial of carbon and release of oxygen. However, the nutrient trace element (TE) composition of the palaeo-ocean cannot be measured directly. Here we present a comprehensive global dataset on the TE content of marine sedimentary pyrite in black shales, dating back 700 million years, and demonstrate a systematic cyclic evolution of pyrite TE composition with time. The nutrient TE, molybdenum, selenium, cadmium and thallium measured in pyrite, and phosphorus measured on whole rock, rise sharply at 560 to 550 Ma followed by several cycles of TE variation through the Palaeozoic and into theMesozoic. A number of factors could explain the trends.We suggest that variations in continental uplift, erosion and nutrient flux rates were possible drivers of the oceanic nutrient cycles. The cyclic patterns through the Phanerozoic suggest periods of nutrient-rich oceans that fostered key evolutionary events, followed by nutrient-poor oceans that encompass several major mass extinction events.

Item Type:	Refereed Article
Keywords:	sedimentary pyrite, palaeo-ocean chemistry, mass extinction, ocean nutrients, metalliferous shales evolution
Research Division:	Earth Sciences
Research Group:	Geology
Research Field:	Tectonics
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Earth Sciences
Author:	Large, RR (Professor Ross Large)
Author:	Halpin, JA (Dr Jacqueline Halpin)
Author:	Lounejeva, E (Ms Elena Lounejeva Baturina)
Author:	Danyushevsky, LV (Professor Leonid Danyushevsky)
Author:	Gregory, D (Dr Daniel Gregory)
Author:	Makoundi, C (Mr Charles Makoundi)
Author:	Stepanov, AS (Mr Sasha Stepanov)
ID Code:	102215
Year Published:	2015
Funding Support:	Australian Research Council (DP150102578)
Web of Science® Times Cited:	23
Deposited By:	Centre for Ore Deposit Research - CODES CoE
Deposited On:	2015-08-04
Last Modified:	2017-10-30
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