A million year vegetation history and palaeoenvironmental record from the Lake Magadi Basin, Kenya Rift Valley

摘要: Abstract This study examines a one-million-year pollen record from 194-m-long Lake Magadi core (HSPDP-MAG14-2A) in the south Kenya Rift Valley. The indicate general trend through last 740 kyr wetter conditions to generally drier environments. Grassland dominated with less common Podocarpus and Cyperaceae sparse flora between 1000 740 ka. Poaceae, woodland herbaceous plants are remaining abundant 528 ka after 200 ka. Pollen diversity increased reached peak abundance at ~575 ka subsequent decline that suggests progressive increase aridity, interrupted by intervals. Podocarpus-dominated forests expanded contracted many times during Quaternary document an anti-phased relationship data Malawi. Similar correlations noted for plants, suggesting two basins responded differently same climate or were influenced contrasting regimes. Increases macrocharcoal correlate increasing suggest conditions. Data Magadi, Koora Olorgesailie similar trends dominant control on vegetation habitats. Large lakes characterised all three 740–528 ka subsequently becoming drier, but At various expanded, dried out, except where spring inflows maintained lacustrine late Quaternary. Faulting also contributed fragmentation of landscape formation mosaic An especially intense period aridity ~528–392 ka coincided extinction large-bodied mammals may have helped drive change use Acheulean hand axes production Middle Stone Age tools 320 ka. After 200 ka substantially mix montane, riparian dry forest associations present varying amounts ~4.2 ka top.