(Table 1) Luminescence datings from Varchushka and Pyoza rivers, Russia@en

The Pyoza River area in the Arkhangelsk district exposes sedimentary sequences suitable for study of the interaction between consecutive Valdaian ice sheets in Northern Russia. Lithostratigraphic investigations combined with luminescence dating have revealed new evidence on the Late Pleistocene history of the area. Overlying glacigenic deposits of the Moscowian (Saalian) glaciation marine deposits previously confined to three separate transgression phases have all been connected to the Mikulinian (Eemian) interglacial. Early Valdaian (E. Weichselian) proglacial, lacustrine and fluvial deposits indicate glaciation to the east or north and consequently glacier damming and meltwater run-off in the Pyoza area around 90-110 ka BP. Interstadial conditions with forest-steppe tundra vegetation and lacustrine and fluvial deposition prevailed at the end of the Early Valdaian around 75-95 ka BP. A terrestrial-based glaciation from easterly uplands reached the Pyoza area at the Early to Middle Valdaian transition around 65-75 ka BP and deposited glaciofluvial strata and subglacial till (Yolkino Till). During deglaciation, laterally extensive glaciolacustrine sediments were deposited in ice-dammed lakes in the early Middle Valdaian around 55-75 ka BP. The Barents–Kara Sea ice sheet deposited the Viryuga Till on the lower Pyoza from northerly directions. The ice sheet formed the Pyoza marginal moraines, which can be correlated with the Markhida moraines further east, and proglacial lacustrine deposition persisted in the area during the first part of the Middle Valdaian. Glacio-isostatic uplift caused erosion followed by pedogenesis and the formation of a deflation horizon in the Middle Valdaian. Widely dispersed periglacial river plains were formed during the Late Valdaian around 10-20 ka BP. Thus, the evidence of a terrestrial-based ice sheet from easterly uplands in the Pyoza area suggests that local piedmont glaciers situated in highlands such as the Timan Ridge or the Urals could have developed into larger, regionally confined ice sheets. Two phases of ice damming and development of proglacial lakes occurred during the Early and Middle Valdaian. The region did not experience glaciation during the Late Valdaian.俄罗斯北部阿尔汉格尔斯克区的皮奥扎河（Pyoza River）流域出露的沉积序列，可用于研究连续瓦尔代冰盖（Valdaian ice sheets）之间的相互作用。岩石地层学调查（Lithostratigraphic investigations）结合光释光测年（luminescence dating），为该地区晚更新世的演化历史提供了新证据。原本被限定为三个独立海侵阶段的莫斯科冰期（萨勒冰期，Moscowian (Saalian) glaciation）冰碛沉积之上的海相沉积，现已全部被归为米库林间冰期（埃姆间冰期，Mikulinian (Eemian) interglacial）的产物。早瓦尔代冰期（Early Valdaian (E. Weichselian)）的冰前、湖相及河流相沉积表明，约90~110 ka BP前后，皮奥扎河地区存在东向或北向冰川作用，进而引发冰川堰塞与融水径流。早瓦尔代冰期末期（约75~95 ka BP），区域以森林草原苔原植被为主，发育间冰阶环境，并伴随湖相与河流相沉积作用。来自东部高地的陆源冰盖在早-中瓦尔代冰期过渡阶段（约65~75 ka BP）抵达皮奥扎河地区，沉积了冰水河相地层与约尔基诺底碛（Yolkino Till）。在冰消期，约55~75 ka BP的早中瓦尔代冰期阶段，冰堰塞湖中沉积了横向分布广泛的冰湖相沉积物。巴伦支-喀拉海冰盖（Barents–Kara Sea ice sheet）从北向在皮奥扎河下游沉积了维留加底碛（Viryuga Till）。该冰盖形成了皮奥扎边缘冰碛垄，其可与更东侧的马尔基达冰碛垄（Markhida moraines）对比；中瓦尔代冰期早期，区域持续发育冰前湖相沉积。冰川均衡抬升（Glacio-isostatic uplift）引发侵蚀作用，随后伴随土壤形成作用，并在中瓦尔代冰期形成了风蚀层。约10~20 ka BP的晚瓦尔代冰期阶段，区域形成了广泛分布的冰缘河漫滩。综上，皮奥扎河地区陆源冰盖来自东部高地的证据表明，坐落于季曼岭（Timan Ridge）或乌拉尔山脉（Urals）等高地的局部山麓冰川，有可能发育为规模更大的区域性局限冰盖。早瓦尔代冰期与中瓦尔代冰期阶段，共发生两期冰川堰塞事件并形成冰前湖泊。晚瓦尔代冰期阶段，该区域未遭受冰川作用。