Concentrations of alkenones in Hala Hu sediment core H7

Concentrations of alkenones were analysed in core H7 from Hala Hu, China by means of an Agilent 7890A gas chromatography (GC) instrument, equipped with a mass selective detector (MSD; Agilent 5975C Series) and a flame ionization detector (FID; Agilent 7683B Series). For the GC, an Agilent VF-200ms column (60 m, inner diameter 0.25 mm, film thickness 0.25 μm) was used. The lake is located on the northern margin of the Tibetan Plateau (97.24 - 97.47°E, 38.12 - 38.25°N, 4078 m above sea level), along the modern marginal zone between the Asian Summer Monsoon (ASM) and westerlies influences. The core was drilled at the deepest point (65 m water depth) of the lake and extends from 212 to 636 cm sediment depth. According to the age-model (Yan et al., 2020) the covered time period is 7462 - 23610 cal yr BP.