Whether all the carbonatite/ carbonate melt are related to the subducted carbonates? How to determine the Origin of Carbonatites in the Mantle and the Contribution of Subducted Carbonates? Although C-O isotopes can distinguish between mantle and surface carbon sources, can the surface carbon-O signal remain unaffected in the deep mantle and preserved over the long term? For example, is the carbonate in carbonated peridotite originally derived from the surface or the mantle itself?