Abstract: As an important part of the lithosphere on the earth surface, the carbonate rocks chemical composition can provide useful information on their sedimentary environment and evolution of marine waters. However, previous studies paid little attention to the distribution characteristics of rare earth elements and other elements in the carbonate rocks. This study examined a total of 582 carbonate rock samples collected along three continentalscale transects in eastern China. The results show that the total concentrations of REE＋Y in the carbonate rocks ranged from 0.59×10-6 to 183×10-6 (average 24.0×10-6), with the mean of 4.80×10-6 in the pure carbonate rocks (CMC≥99％). Compared with MREE and HREE, LREE depletion was observed after PAASnormalization, with weak positive δEu anomaly and moderate negative δCe anomaly. Values of REEs and LREE/HREE in dolomite were generally lower than those in limestone. When the contents of sand and mud were similar, the distribution patterns of carbonate rocks were similar in different tectonic units during the preMesozoic era. Compared with the other eras, the Mesozoic and Mesoproterozoic carbonate rocks had relatively flat distribution patterns. This study proves that the distribution of REEs in carbonate rocks is obviously influenced by detrital material. Meanwhile, the concentrations of REE＋Y were negatively correlated with CO2-3 and positively correlated with the elements in the detrital material (Si, Ti, Rb, Cs, Th, Zr, etc) and in clay (Al, Fe, K, etc). The diagenesis and dolomitization had little effect on the distribution of REE＋Y in the pure carbonate rocks. The distribution pattern of Paleozoic pure carbonate rocks in eastern China was controlled by the marine environment, which was very similar to the pattern of current seawater. The Mesozoic pure limestone was affected by terrestrial facies or marineterrigenous facies, with a relatively flat REE＋Y distribution pattern. The δCe value was controlled by the marine environment, and the extreme positive anomaly (δCe＞1.3) was affected by the reducing environment/hydrothermal solution, which led to even more significant effect of redox conditions on the δCe than δEu. When the REEs in seawater had no obvious change since the Middle Proterozoic, and the mean value of REE＋Y partition coefficient was between 103.55 and 102.39, the LREE depletion, negative anomaly of Ce and positive anomaly of Y were mainly due to differences in the distribution coefficient. Microorganisms could enrich REEs and change the sedimentary environment, it might be the main reason for the flat REE＋Y distribution pattern in the MiddleUpper Proterozoic carbonate rocks.

Key words:  continentalscale transects in eastern China, rare earth elements, carbonate rocks, sedimentary environment