CO2: recycling to the deep convecting mantle

F. E. Brenker, Christian Vollmer, Laszlo Vincze, Bart Vekemans, Anja Szymanski, Koen Janssens, Imre Szaloki, Lutz Nasdala, Werner Joswig, F. Kaminsky

Research output: Contribution to journalMeeting abstractpeer-review


Synchroton X-ray probe. We applied several in situ analytical techniques (S-XRF, S-XRD, Raman) ( Brenker, 2005; Vincze, 2004; Vekemans, 2004 ; Nasdala, 2003) on syngenetic inclusions in diamonds from Juina (Brazil) originating from the lower part of the transition zone (>580 km) or even the lower mantle (>670 km). Our investigation yielded an unusual suite of “ultra-deep” diamonds, dominated by Ca-rich mineral inclusions. Walstromite-structured CaSiO3 inclusions were identified in 13 cases. The most unexpected finding in these deep mantle diamonds was the detection of several syngenetic carbonate inclusions. The coexistence of a walstromite-structured CaSiO3, and olivine with syngenetic calcite within the same diamond, together with the finding of a two phase assemblage of walstromite-structured CaSiO3 and CaTiO3-perovskite, leads to the assumption that the carbonate was incorporated into the diamond in the lower part of the transition zone (>580 km depth) or even the lower mantle.

Implications. These findings unquestionably show that Earth’s global CO2-cycle has an ultra-deep extension. The storage of carbonates in the deep mantle enable the release of huge amounts of CO2 during mantle melting events, which may explain the coincidence of mass extinctions with the formation of large igneous provinces (Wignal, 2005).
Original languageEnglish
Pages (from-to)A66-A66
Number of pages1
JournalGeochimica et Cosmochimica Acta
Issue number18, Supplement
Publication statusPublished - Aug 2006
Externally publishedYes
EventGoldschmidt Conference (16th : 2006) - Melbourne, Australia
Duration: 27 Aug 20061 Sep 2006


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