Sulphur isotopes of alkaline magmas unlock longterm records of crustal recycling on Earth

Earth’s surface and mantle sulphur reservoirs are connected via subduction, crustal recycling and volcanism. Although oceanic hotspot lavas currently provide the best constraints on the deep sulphur cycle, their restricted age range (<200 Ma) means they cannot reveal temporal variations in crusta...

Full description

Bibliographic Details
Published in:Nature Communications
Main Authors: Hutchison, William, Babiel, Rainer J., Finch, Adrian A., Marks, Michael A. W., Markl, Gregor, Boyce, Adrian J., Stüeken, Eva E., Friis, Henrik, Borst, Anouk M., Horsburgh, Nicola J.
Format: Article in Journal/Newspaper
Language:English
Published: 2019
Subjects:
Greenland
Online Access:http://hdl.handle.net/10852/74310
http://urn.nb.no/URN:NBN:no-77415
https://doi.org/10.1038/s41467-019-12218-1
Description
Summary:Earth’s surface and mantle sulphur reservoirs are connected via subduction, crustal recycling and volcanism. Although oceanic hotspot lavas currently provide the best constraints on the deep sulphur cycle, their restricted age range (<200 Ma) means they cannot reveal temporal variations in crustal recycling over Earth history. Sulphur-rich alkaline magmas offer the solution because they are associated with recycled sources (i.e. metasomatized lithospheric mantle and plumes) and, crucially, are found throughout the geological record. Here, we present a detailed study of sulphur isotope fractionation in a Mesoproterozoic alkaline province in Greenland and demonstrate that an enriched subduction-influenced source (δ34S of +1 to +5‰) can be reconstructed. A global δ34S compilation reveals secular variation in alkaline magma sources which support changes in the composition of the lithospheric mantle and/or Ga timescales for deep crustal recycling. Thus, alkaline magmas represent a powerful yet underutilized repository for interrogating crustal recycling through geological time.

Similar Items