Marine carbonate inter-REE + Y ratios indicate mixing between fresh water and seawater. Stratigraphic variations in REE + Y pattern indicate changes in proportion of adding fresh water. Carbonate carbon and oxygen isotopes indicate changes in sedimentary environment and diagenesis. There are coupled changes in fresh water addition and diagenetic zones for marine carbonates. Fresh water may add to marine carbonates due to seafloor weathering and surface runoff on continental substrate.