(Table 2) Rare earth elements concentrations of the carbonates analyzed

Rare earth elements concentrations (ppm; 5% HNO3-treated solution).a: micry, microcrystalline matrix; spcry, later cement; shell, bivalve shells.稀土元素浓度（单位：ppm，样本为经5%硝酸处理的溶液）。a类：micry（微晶基质，microcrystalline matrix）；spcry（后期胶结物，later cement）；shell（双壳类贝壳，bivalve shells）