Durham geochemists explain problematic signatures from the Earth's core

(30 January 2008)

The observation in some plume related lavas of enrichments in the radiogenic daughter products of Re and Pt isotopes, occurring as enriched 186Os and 187Os signatures has been attributed to mass exchange across the core mantle boundary. This was held to be the deepest chemical signature of the Earth’s internal workings that is observable at the Earth’s surface. This explanation has been a significant problem for geophysicists trying to model the timing of formation of the Earth’s inner core in relation to the thermal history of the earth and so the two disciplines have been in conflict. In a recent edition of Science, NCIET geochemists provide an elegant alternative explanation for this enigmatic signature that requires no input from an enriched outer core and hence removes the problems of the need for an early formed core in modelling the Earth’s thermal history. The paper is highlighted in an associated “perspectives” piece entitled “The rise and fall of a great idea”. The reference is: A.L. Luguet, D.G. Pearson G. M. Nowell, S. T. Dreher , J. A. Coggon , Z.V. Spetsius and S. W. Parman Enriched Pt-Re-Os isotope systematics in plume lavas explained by metasomatic sulfides, Science, 319, 453-456.