Lacustrine transgressions in the late Cenozoic Ussuri-Khanka depression (Primor’e)

Environmental evolution of Xingkai (Khanka) Lake since 200 ka by OSL dating of sand hills

“…(2) A lacustrine transgression occurred at about 136 ka in the Ussuri-Khanka Depression [30], at which time the lakeshore line moved back to Er'dao Hill, where it stayed until another regression occurred at about 130 ka. Palynomorphs from the base of the silty sequence of the Nakhodka Horizon, which are an indicator of lake shoaling, suggested a gradual transition from landscapes of dark coniferous taiga to broad-leaved forest of the Manchurian type [28]. During 130-25 ka, Xingkai Lake did not pass beyond Er'dao Hill, although there were several stages in which the shoreline fluctuated on the north side based on previous studies.…”

“…The evolutionary history of Xingkai Lake was rebuilt based on OSL datings and the results of previous studies conducted in the Ussuri-Khanka depression of Primorye [28]. The results revealed a regressive stepwise trend that included at least four transgressions (during 193-183 ka, 136-130 ka, 24-15 ka and since 3 ka) and three depressions.…”

“…(1) At around 200 ka, Xingkai Lake had a much larger surface area than at present day and the north shoreline remained along Huangnan Hill for a long time. At the same time, geological data recorded from the Ilistaya and Mel'gunovka Rivers showed that a conjoint limnic reservoir existed within the downstream reach [29]. Since 183 ka, Xingkai Lake has regressed rapidly, and the north shoreline has moved away from Huangnan Hill.…”

“…For example, a higher sand content and a bed of quartz-feldspar beach sand with well-rounded gravel and pebbles in the core were deposited on the coastal shoals, close to the Mel'gunovka River estuary, which marked a new short-term transgression [31]. In the northern part of the basin, this regression was accompanied by the emergence of a spacious lowland swamp [29]. Owing to the destruction by the larger transgression that occurred later, there was little evidence of this transgression remaining on the land.…”

“…(3) From about 24 ka, Xingkai Lake extended, with Taiyang Hill forming on the north and northeast side. This period marked a powerful transgression of Xingkai Lake, with a reported increase in the water level from 1.5 to 4.0 m above the present lake level [28]. In addition to the current rivers, the Belaya and Muling Ho rivers flowed into the lake at the east and west side, respectively [32].…”