TY  - JOUR
A1  - Aulbach, Sonja
A1  - Stachel, Thomas
T1  - Evidence for oxygen-conserving diamond formation in redox-buffered subducted oceanic crust sampled as eclogite
T2  - Nature Communications
N2  - Cratonic eclogite is the product of oceanic crust subduction into the subcontinental lithospheric mantle, and it also is a fertile diamond source rock. In contrast to matrix minerals in magma-borne xenoliths, inclusions in diamond are shielded from external fluids, retaining more pristine information on the state of the eclogite source at the time of encapsulation. Vanadium is a multi-valent element and a widely used elemental redox proxy. Here, we show that that xenolithic garnet has lower average V abundances than garnet inclusions. This partly reflects crystal-chemical controls, whereby higher average temperatures recorded by inclusions, accompanied by enhanced Na2O and TiO2 partitioning into garnet, facilitate V incorporation at the expense of clinopyroxene. Unexpectedly, although diamond formation is strongly linked to metasomatism and xenoliths remained open systems, V concentrations are similar for bulk eclogites reconstructed from inclusions and from xenoliths. This suggests an oxygen-conserving mechanism for eclogitic diamond formation, and implies that eclogite is an efficient system to buffer fO2 over aeons of lithospheric mantle modification by subduction-derived and other fluids.
KW  - Mineralogy
KW  - Petrology
Y1  - 2022
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/69510
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-695108
SN  - 2041-1723
N1  - Open Access funding enabled and organized by Projekt DEAL.
VL  - 13
IS  - art. 1924
SP  - 1
EP  - 13
PB  - Nature Publishing Group UK
CY  - [London]
ER  -