Figure 5. Variations in ¹³C (A) and ¹⁸O (B) of carbonate minerals (calcite, dolomite, and siderite) in sediments from Sites 994, 995, and 997 are shown. The corresponding data are given in Table 2. The sulfate/methane interface is indicated by a dashed line. The gas hydrate-bearing section of the sediment column is shaded.