Stefan Farsang1, Marion Louvel2, Chaoshuai Zhao3, Mohamed Mezouar4, Angelika D Rosa4, Remo N Widmer5, Xiaolei Feng6,3, Jin Liu3, Simon A T Redfern7. 1. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK. sf571@cam.ac.uk. 2. Institut für Mineralogie, WWU Münster, Münster, 48149, Germany. 3. Center for High Pressure Science and Technology Advanced Research (HPSTAR), Beijing, 100094, China. 4. European Synchrotron Radiation Facility, 71 Avenue des Martyrs, Grenoble, 38000, France. 5. Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Mechanics of Materials and Nanostructures, Feuerwerkerstrasse 39, Thun, 3602, Switzerland. 6. Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EQ, UK. 7. Asian School of the Environment, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore. simon.redfern@ntu.edu.sg.
Abstract
Earth's deep carbon cycle affects atmospheric CO2, climate, and habitability. Owing to the extreme solubility of CaCO3, aqueous fluids released from the subducting slab could extract all carbon from the slab. However, recycling efficiency is estimated at only around 40%. Data from carbonate inclusions, petrology, and Mg isotope systematics indicate Ca2+ in carbonates is replaced by Mg2+ and other cations during subduction. Here we determined the solubility of dolomite [CaMg(CO3)2] and rhodochrosite (MnCO3), and put an upper limit on that of magnesite (MgCO3) under subduction zone conditions. Solubility decreases at least two orders of magnitude as carbonates become Mg-rich. This decreased solubility, coupled with heterogeneity of carbon and water subduction, may explain discrepancies in carbon recycling estimates. Over a range of slab settings, we find aqueous dissolution responsible for mobilizing 10 to 92% of slab carbon. Globally, aqueous fluids mobilise [Formula: see text]% ([Formula: see text] Mt/yr) of subducted carbon from subducting slabs.
Earth's deep carbon cycle afpan class="Chemical">fects atmospheric CO2, climate, and habitability. Owing to the extreme solubility of CaCO3, aqueous fluids released from the subducting slab could extract all carbon from the slab. However, recycling efficiency is estimated at only around 40%. Data from carbonate inclusions, petrology, and Mg isotope systematics indicate Ca2+ in carbonates is replaced by Mg2+ and other cations during subduction. Here we determined the solubility of dolomite [CaMg(CO3)2] and rhodochrosite (MnCO3), and put an upper limit on that of magnesite (MgCO3) under subduction zone conditions. Solubility decreases at least two orders of magnitude as carbonates become Mg-rich. This decreased solubility, coupled with heterogeneity of carbon and water subduction, may explain discrepancies in carbon recycling estimates. Over a range of slab settings, we find aqueous dissolution responsible for mobilizing 10 to 92% of slab carbon. Globally, aqueous fluids mobilise [Formula: see text]% ([Formula: see text] Mt/yr) of subducted carbon from subducting slabs.
Authors: O Tschauner; S Huang; E Greenberg; V B Prakapenka; C Ma; G R Rossman; A H Shen; D Zhang; M Newville; A Lanzirotti; K Tait Journal: Science Date: 2018-03-09 Impact factor: 47.728
Authors: J M de Moor; D Giovannelli; K G Lloyd; P H Barry; M Schrenk; D R Hummer; T Lopez; C A Pratt; Y Alpízar Segura; A Battaglia; P Beaudry; G Bini; M Cascante; G d'Errico; M di Carlo; D Fattorini; K Fullerton; E Gazel; G González; S A Halldórsson; K Iacovino; T Ilanko; J T Kulongoski; E Manini; M Martínez; H Miller; M Nakagawa; S Ono; S Patwardhan; C J Ramírez; F Regoli; F Smedile; S Turner; C Vetriani; M Yücel; C J Ballentine; T P Fischer; D R Hilton Journal: Nature Date: 2019-04-24 Impact factor: 49.962