A METHOD FOR QUANTIFYING DEEP-SEA CARBONATE DISSOLUTION USING C-14 DATING

We quantified the rate of carbonate dissolution with increasing water depth by taking the difference in the carbonate mass accumulation rate of deep (3393-4375 m) core top sediments from the shallowest one (320 8 m), which we assumed was unaffected by dissolution. This method depe nds on high quality C-14 dates that we calibrated to calendar years fo r calculating sedimentation rates. Our results show low (ranging from 0 to 0.3 g cm(-2) ka(-1)) and high (ranging from 1.5 to 1.7 g cm(-2) k a(-1)) carbonate dissolution rates, above and below 4000 m, respective ly. Therefore, we interpret the sudden increase in the carbonate disso lution rate at 4000-m water depth to mark the lysocline.