The carbon is also abundant in the rocks, and it persists through a thick pile of ancient sediments that represents as much as a million or more years of slow deposition.

• 岩石中也有很丰富的碳，厚厚的古老沉积岩中一直都有碳的存在，这层沉积岩代表了超过百万年的缓慢沉淀过程。