Paleovegetation and paleoclimate changes in southeastern part of the Korean peninsula over the last 30 kyr inferred from plant wax carbon isotopes

Abstract

This study reconstructs past vegetation changes in southeastern Korea over the last 30 thousand years using plant waxes (i.e. long chain n-alkanes) and their carbon isotopic compositions (δ 13 C alk ) preserved in marine sediment core (KIODP 12-1) retrieved from the East Sea. Here we show changes in vegetation composition in the Korean peninsula in relation to the strength of the East Asian Summer Monsoon. During the Last Glacial Maximum (LGM), when the summer monsoon weakened, precipitation decreased and C 3 grassland expanded. After the LGM, the summer monsoon gradually intensified, increasing rainfall, and thus expanding the forestland coverage. Precipitation climaxed from 10 to 6 kyr BP, which includes the Holocene Climate Optimum. The grassland began to expand since 5 kyr BP due to climate warming and drying towards the present. The δ 13 C alk values may also have been influenced by agricultural activities, which is known to have begun since the late Neolithic (ca. 7.0~3.0 kyr BP). Our results demonstrate how changes in the global climate state influence regional atmospheric circulation and precipitation distribution, and consequently terrestrial plant composition in southeastern Korea. © 2018, Korea Ocean Research and Development Institute. All rights reserved.