CaCO3 resources for carbon fuels production

AI Google: The Numbers: CaCO₃ vs. Oil & Gas Resource Type Estimated Global Reservoir Size (in Carbon Mass) Equivalency in Metric Tons (Gt / Mt) Calcium Carbonate (CaCO₃) ~40,000,000 Gigatons (Gt) 40,000,000,000 Million Tons (Mt) All Fossil Fuels (Oil, Gas, & Coal) ~4,000 to 5,000 Gigatons (Gt) ~4,000,000 to 5,000,000 Million Tons (Mt) Why is the Google: difference so massive? 1. The Earth's Largest Carbon Sink: Calcium carbonate is the single largest reservoir of carbon on the planet. Over 99% of all the carbon on Earth is locked up in the crust, predominantly as sedimentary limestone rocks formed over hundreds of millions of years from the shells and skeletons of marine organisms. [1, 2, 3] 2. Efficiency of Formation: When marine life dies, its carbonate shells reliably settle to the ocean floor to form rock layers miles thick. By contrast, fossil fuels (oil and gas) require highly specific, rare, and oxygen-depleted geological "trap" conditions to form from organic mud. Only a tiny fraction of a percent of ancient organic life ever successfully turned into oil or gas. [1, 2, 3, 4] 3. Crustal Abundance: CaCO₃ makes up roughly 4% of the Earth's total crust. It is so abundant that economic "reserves" are practically limitless compared to human consumption, whereas oil and gas reserves are finite and measured strictly by what is technically and economically extractable. [1, 2] An interesting geological overlap is that more than 50% to 60% of the world's oil and gas reserves are actually trapped inside the porous fractures of these massive calcium carbonate fields (known as carbonate reservoirs). [1, 2] Are you researching this from a carbon sequestration/capture perspective, or are you looking at the commercial availability of limestone for industrial cement and manufacturing uses? Let me know so I can provide more specific data!