Major and trace element concentrations of thirteen limestone samples from zone XX of the Tlayúa Quarry Fossillagerstätte were analysed with the aim of elucidating the source of rare earth elements plus yttrium (REE+Y) as well as some palaeoenvironmental conditions attributable to them. The concentrations of cortex-derived elements/element oxides (SiO₂, Al₂O₃, Zr), as well as of phosphorus, show no significant contamination by means of terrigenous material and/or phosphates, which means that the REE+Y concentrations can be interpretable. REE+Y patterns display partly typical modern seawater signals, particularly positive La and Y anomalies, mostly superchondritic Y/Ho ratios (between 42.34 and 56.38) and moderate depletions of light rare earth elements (LREE) and middle rare earth elements (MREE) in comparison to heavy rare earth elements (HREE) (x̄ Pr_SN/Yb_SN = 0.12, x̄ Nd_SN/Yb_SN = 0.14 and x̄ Dy_SN/Yb_SN = 0.42, respectively). Negative cerium anomalies could also be identified [(Ce/Ce*_SN) = 0.73], which indicate oxidising conditions. In addition, positive Eu anomalies [(Eu/Eu*_SN) = 2.53] were detected. Since no convincing evidence for diagenesis, hydrothermal or aeolian input exists, the origin of these anomalies can, to some extent, be attributable to the influence of the dissolution of plagioclases in the water column, which can be inferred from the bivariate correlation of (Eu/Eu*)_SN and Na/Al. Despite depicting modern seawater-like signals, an important difference between the REE+Y patterns from zone XX of the Tlayúa Quarry and modern seawater REE+Y patterns can be determined. For instance, modern seawater does not display significant europium anomalies. Nevertheless, REE+Y patterns from zone XX of the Tlayúa Formation can altogether be reliable palaeoenvironmental proxies for the Cretaceous. The inferred palaeoenvironment for zone XX from these proxies is represented by an open-marine setting, showing oxidising conditions, evidence of plagioclase dissolution and overall negligible terrigenous influence. The palaeoecological interpretation from these patterns does not exclude, however, the probability of monsoonal or tidally influenced sedimentation in other sediments from zone XX or from other zones in Tlayúa, as previous works suggest.

分析了Tlayúa采石场FossillagerstätteXX区的13个石灰岩样品的主要和痕量元素浓度，目的是阐明稀土元素和钇（REE + Y）的来源以及可归因于它们的某些古环境条件。皮质衍生元素/元素氧化物（SiO ₂，Al ₂ O ₃，Zr）以及磷，都不会受到陆源材料和/或磷酸盐的污染，这意味着REE + Y浓度是可以解释的。REE + Y模式显示出部分典型的现代海水信号，特别是正的La和Y异常，主要是超软骨质的Y / Ho比（介于42.34和56.38之间）以及中等损耗的轻稀土元素（LREE）和中稀土元素（MREE）比较重稀土元素（HREE）（X镨_SN /镱_SN = 0.12，X钕_SN /镱_SN = 0.14和X的Dy _SN /镱_SN分别为0.42）。负的铈异常也可以被识别[（Ce / Ce * _SN）= 0.73]，这表明氧化条件。另外，检测到正Eu异常[（Eu / Eu * _SN）= 2.53]。由于没有令人信服的成岩，热液或风成因的证据，因此这些异常的起源在一定程度上可归因于斜纹岩在水柱中的溶解影响，这可以从（Eu / Eu *）_SN和Na / Al。尽管描绘了类似现代海水的信号，但可以确定Tlayúa采石场XX区的REE + Y模式与现代海水REE + Y模式之间的重要区别。例如，现代海水并没有显示出明显的euro异常。尽管如此，Tlayúa组XX区的REE + Y模式完全可以作为白垩纪古环境的可靠代表。从这些代理推断出的XX区古环境以开放的海洋环境为代表，显示出氧化条件，斜长石溶解的证据以及总体上可忽略的陆源影响。从这些模式的古生态解释不排除季风或潮汐影响XX区或Tlayúa其他区沉积物中的沉积的可能性，