AI Article Synopsis
- Earth's deep carbon cycle plays a crucial role in influencing atmospheric CO2 levels, climate, and the overall habitability of the planet.
- Subducting slabs can release carbon through aqueous fluids, but only about 40% of this carbon is estimated to be recycled back into the Earth's systems.
- New research indicates that the solubility of carbonates decreases significantly when they become magnesium-rich, which may clarify the variations in carbon recycling estimates during subduction processes.
Article Abstract
Earth's deep carbon cycle affects atmospheric CO, climate, and habitability. Owing to the extreme solubility of CaCO, 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 Ca in carbonates is replaced by Mg and other cations during subduction. Here we determined the solubility of dolomite [CaMg(CO)] and rhodochrosite (MnCO), and put an upper limit on that of magnesite (MgCO) 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.
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Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8280166 | PMC |
| http://dx.doi.org/10.1038/s41467-021-24533-7 | DOI Listing |
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