Abstract
The early to middle Holocene Humid Period (HHP) was the last time when
precession-forced intensification of summer monsoons and northward
migration of associated rainfalls led to a greening of today’s arid
Saharo-Arabian desert belt. While this wet phase is well confined in N
Africa and the S Arabian Peninsula, robust evidence from N Arabia is
lacking. Here, we fill this gap with unprecedented annually to
sub-decadally resolved proxy data from Tayma, the only known varved lake
sediments in N Arabia. Based on stable isotopes, micro-facies analyses
and precise varve and radiocarbon dating we distinguish five phases of
lake development and prove that the wet phase in N Arabia from
8,800–7,900 years BP is considerably shorter than the commonly defined
HHP (11,000–5,500 years BP). Moreover, we find a two century-long peak
humidity at Tayma at times when a centennial-scale dry anomaly around
8,200 years BP interrupted the HHP in adjacent regions. This regional
disparity is explained by an increased frequency of tropical plumes
reaching N Arabia and compensating for the weakened monsoons and/or
winter rains. This peak humidity possibly favoured Neolithic migrations
into N Arabia indicating very dynamic human response to environmental
changes.