Yellowstone is on top of huge boiling reservoir of liquid carbonate

A Fiery Monster Lump is Bubbling Beneath Yellowstone’s Supervolcano, Reveals Study

“A colossal lump of molten carbonates is bubbling hundreds of kilometers underneath Yellowstone Park’s supervolcano, and the discovery has changed scientists’ understanding of the carbon cycle.
About 1.8 million square kilometers (700,000 square miles) in size, the liquidized, carbon-infused material lurks in the upper region of the mantle, a research published in the journal Earth and Planetary Science Letters has revealed.”