Abstract The extraction of palaeoenvironmental (palaeoclimatic) signals from the chemical composition of siliciclastic sediments is valuable for the reconstruction of past environments, particularly in continental basins. Here we test novel weathering proxies, which are less sensitive to lithological control than the previously used raw element ratios K/Al, K/Ti, and K/Rb: (1) local enrichment factors of K/Al, Mg/Al, and K/Rb, i.e., the element ratios corrected for grain size- and matrix composition using local background functions (Al/Si, Fe, and Ca as explanatory variables) and ordinary regression and (2) robust regression residuals of those element ratios based on isometric log-ratio coordinates of the most relevant “lithogenic” elements (Ca, Fe, Rb, Si, Zr) in the chemical composition. Chemical weathering proxies can be obtained from departures of chemical composition of sedimentary profiles from relationships with other chemical elements, in particular those with grain-size control. The resulting weathering proxies were examined for the Miocene deposits from the Most Basin, the Czech Republic, which recorded one of the major warm episodes of the Cenozoic time – the Miocene Climatic Optimum. The performance of weathering proxies has been checked by (1) comparison of individual proposed proxies in one drill core HK930, (2) detailed analysis of orbital signals in the relevant compositional functions in HK930; and (3) lateral correlation of three cores HK930, DU7, and DO565 of the same basin. The novel proxies show lateral stability and orbital signatures of short eccentricity, obliquity, and precession, confirming their usefulness in palaeoenvironmental studies. Corrections for grain-size and carbonate contents should help to isolate climatic content from the weathering proxies, although in the studied sediments it weakened the precession component in the orbital signal, as grain-size proxies and other compositional data also carried orbital signals. We propose to consider these proxy ideas in palaeoclimatic reconstructions based on chemical weathering proxies.

中文翻译：

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基于 K、Rb 和 Mg 含量的化学风化替代物的岩性校正，用于隔离碎屑沉积档案中的轨道信号

摘要 从硅质碎屑沉积物的化学成分中提取古环境（古气候）信号对于重建过去环境，尤其是在大陆盆地中的环境具有重要意义。在这里，我们测试了新的风化代理，与以前使用的原始元素比率 K/Al、K/Ti 和 K/Rb 相比，它们对岩性控制的敏感性较低：（1）K/Al、Mg/Al 和K/Rb，即使用局部背景函数（Al/Si、Fe 和 Ca 作为解释变量）和普通回归以及 (2) 这些元素比率的稳健回归残差根据晶粒尺寸和基体成分校正的元素比率化学成分中最相关的“成岩”元素（Ca、Fe、Rb、Si、Zr）的等距对数比坐标。化学风化代理可以从沉积剖面的化学成分与其他化学元素的关系的偏离中获得，特别是那些具有粒度控制的化学元素。对来自捷克共和国莫斯特盆地的中新世沉积物的风化代理进行了检查，该沉积物记录了新生代时期的主要温暖事件之一——中新世气候最佳时期。风化代理的性能已经通过（1）一个钻芯 HK930 中各个建议代理的比较，（2）HK930 相关成分函数中轨道信号的详细分析；(3) 同盆HK930、DU7、DO565 3个岩心横向对比。新的代理显示横向稳定性和短偏心率、倾斜度和进动的轨道特征，证实它们在古环境研究中的有用性。对粒度和碳酸盐含量的修正应该有助于将气候含量与风化代理区分开来，尽管在研究的沉积物中它削弱了轨道信号中的进动分量，因为粒度代理和其他成分数据也带有轨道信号。我们建议在基于化学风化代理的古气候重建中考虑这些代理思想。