Loess-palaeosol deposits of the Upper Pleistocene cover an extensive territory in the south of Western Siberia. Previously, most studies of loess-palaeosol sequences were carried out on river bank sections of the Ob river around Novosibirsk and upstream of this location (Ob Loess plateau); more recently, the focus of research has shifted towards the inner part of the Cis-Altai plain. Despite a good knowledge of the structure of regional loess-palaeosol sequences, there is a considerable lack of absolute dating beyond the radiocarbon limit. However, recent high resolution luminescence dating of a key Marine Isotope Stage 5 (MIS 5) stratotype at Lozhok has identified the presence of a long hiatus in the deposit. As a result, the published ages of the main units have been underestimated, because the existing chronology is largely based on palaeosol counting. This new observation argues for an urgent re-evaluation of the accepted chronostratigraphy of Western Siberian Late Quaternary. Here we present the first luminescence data for a loess-palaeosol sequence of the Cis-Altai plain, at the Solonovka key section, using both quartz optically stimulated luminescence and feldspar post-infrared infrared stimulated luminescence from 25 samples. The results show that the deposits were formed during the Late Pleistocene. The ∼1 m thick well-developed upper pedocomplex (PC1) has cryoturbation cracks filled with upper loess; this a characteristic regional benchmark for stratigraphic correlation. Two distinct hiatuses in sedimentation are found in the section: at the boundary of MIS 3/2, and after the formation of the MIS 5 Berdsk pedocomplex (PC3 and 2) until the beginning of the formation of MIS 3 deposits. The age of the thick PC3 palaeosol at the base of the section is determined as MIS 5, confirming evidence for the pronounced Kazantsevo (Eemian) interglacial in the loess-palaeosol record of Western Siberia. The results of our study emphasize the importance of understanding the palaeogeomorphological background to soil development, and the necessity of absolute chronology; we consider that the position of MIS 5 in the regional chronostratigraphic chart of South Western Siberia requires further study.

上更新世的黄土-古土壤沉积物覆盖了西西伯利亚南部的广阔领土。此前，大部分黄土-古土壤序列研究都是在新西伯利亚附近的鄂毕河河岸段和该位置上游（鄂毕黄土高原）进行的；最近，研究的重点转向了独联体-阿尔泰平原的内部。尽管对区域黄土-古土壤序列的结构有很好的了解，但仍然缺乏超出放射性碳极限的绝对年代测定。然而，最近对 Lozhok 关键海洋同位素第 5 期 (MIS 5) 层型的高分辨率发光测年已确定该矿床中存在长期中断。结果，主要单位的出版年龄被低估了，因为现有的年表主要基于古土壤计数。这一新的观察结果主张对西西伯利亚晚期第四纪公认的年代地层学进行紧急重新评估。在这里，我们使用来自 25 个样品的石英光激发发光和长石后红外红外激发发光，展示了位于 Solonovka 关键部分的 Cis-Altai 平原黄土-古土壤序列的第一个发光数据。结果表明，该矿床形成于晚更新世。～1 m 厚发育良好的上土复合体（PC1）具有充满上层黄土的低温扰动裂缝；这是地层相关性的典型区域基准。在该剖面中发现了两个明显的沉积中断：在 MIS 3/2 的边界，在 MIS 5 Berdsk 土壤复合体（PC3 和 2）形成之后，直到 MIS 3 矿床开始形成。该剖面底部的厚 PC3 古土壤的年龄被确定为 MIS 5，证实了西西伯利亚黄土-古土壤记录中明显的 Kazantsevo (Eemian) 间冰期的证据。我们的研究结果强调了了解古地貌背景对土壤发育的重要性，以及绝对年代学的必要性；我们认为MIS 5在西南西伯利亚区域年代地层图中的位置需要进一步研究。证实了西西伯利亚黄土-古土壤记录中明显的 Kazantsevo (Eemian) 间冰期的证据。我们的研究结果强调了了解古地貌背景对土壤发育的重要性，以及绝对年代学的必要性；我们认为MIS 5在西南西伯利亚区域年代地层图中的位置需要进一步研究。证实了西西伯利亚黄土-古土壤记录中明显的 Kazantsevo (Eemian) 间冰期的证据。我们的研究结果强调了了解古地貌背景对土壤发育的重要性，以及绝对年代学的必要性；我们认为MIS 5在西南西伯利亚区域年代地层图中的位置需要进一步研究。