New evidence of the Vuoksi River origin by geodynamic cataclysm

Abstract

The territory of investigations is located in the SE periphery of the Fennoscandian Shield. It served as an arena of periodic significant restructuring of the hydrographic network associated with the filling and discharge of large late-glacial and Holocene basins during the degradation of the Scandinavian ice sheet and in postglacial time. One such restructuring is a sudden change of the Saimaa Lake direction of flow in the middle Holocene from the west to south to the Lake Ladoga basin via the drainage hollow, inherited by modern Vuoksi River valley. Origin of the Vuoksi River is associated with the catastrophic water breakthrough of the Saimaa Lake across the marginal ridge Salpausselkä I of about 5.7 cal. kyr BP. This event usually connects with water accumulation and overflow due to non-uniform post-glacial uplift according to modern concepts. The authors propose a great earthquake as the immediate cause of the break waters of Saimaa Lake. This suggestion is based on the study of specific deformations of the rocky riverbed in the area of breakthrough and of the loose deposits in the banks of the Vuoksi River valley downstream. Open cracks and horizontally displaced rock blocks were discovered in the area of the former rapids near town Imatra. Their systematic displacements on the both sides of the rocky gorge indicate the shear kinematics of fault zone. Different types of deformations had occurred in loose sediments of the low terraces (3-4 m) in the Vuoksi River valley and 20-30 km below the headwaters. In three studied stratigraphic sections the three cardinal different types of deformations 276

Возраст, Генезис И Сейсмогенные Деформации Террас Реки Вуокса На Карельском Перешейке, Северо-Запад России

“…[Remes et al, 2013]. Полученные данные о возрасте деформации толщи, синхронном этому событию, подтверждают гипотезу о воздействии землетрясения на прорыв озера Сайма [Никонов, 2017;Subetto et al, 2018]. Наклон рыхлой толщи может соответствовать вертикальным смещениям фундамента амплитудой до первых метров, что определяет интенсивность сейсмического события 8-9 баллов.…”

The Monitoring of Sediment Protists in Lake and River Basins Based on Digital Holographic Microscopy

“…In metagenomic sequencing, tag sequencing can capture low-abundance groups, and miTags can accurately reveal dominant groups with less preference. The combination of the two provides an efficient research tool for microbial research [12][13].…”