160 m.y. record of marine sedimentary phosphorus burial: Coupling of climate and continental weathering under greenhouse and icehouse conditions

Abstract

A compilation of all meaningful phosphate data published in the proceedings of the Deep Sea Drilling Project and the Ocean Drilling Program is used here for the extraction of a 160 m.y. marine burial record of bulk phosphorus (all sediment types; 5648 measurements) and a 100 m.y. marine burial record of biogenic phosphorus (pelagic, biogenic, sediment types; 1754 data). These records serve as estimates for total and dissolved (bioavailable) phosphorus flux rates, which in turn are highly dependent on total and chemical continental weathering rates, respectively. The similarity of both records indicates that in the past 100 m.y., changes in total weathering rates may have been tracked by changes in chemical weathering rates. Prior to 32 Ma, phosphorus burial and long-term sea-level change are positively correlated; from 32 Ma to the present, this correlation is inverse. This points to a fundamental change in feedback mechanisms between continental weathering, phosphorus, and climate which was probably linked to the onset of major glaciation.