The cenozoic sediment in Linxia Basin

Which locates at the northeastern fringe of Tibet plateau bears abundant informations on the plateau's uplift and paleoclimate.By means of the Factor Analysismethode to deal with the oxides

the inferred palaeoclimatic information since about 30MaBP basically coincides with that revealed by spore pollen combinations

i.e

during most of teritiary

although climate alternated by warm moisture and cold dryness

it generally represented a relative stable regiem. After stepping into pliocene

climatic unstablity increased clearly

alternated drastically and frequently by the periodes of cold dryness and warm moisture.Untill in early q Quaternary

a cold wet regiem appeared.This processes perhaps reflects to acertain degree a bynamic process which the Asia monsoondisplayed unobviously from before pliocene to establishing progressively in pliocene

untill to stable establishement in early Quaternary. Fluctuatins of geochemical contents are of profound tectonic climatic background

the periodes of geochemical contents fluctuated violently generally correspond to active tectonic periode

climate turned to cold.Spectrum analuses of the high resolutin CaCO 3 curve show that during 30Ma～0.73Ma

climate was mainly controlledby 21ka and 41ka cycles;but during 1.67MA～0.73Ma

the quasi 100ka cycle appeared

and clearly more and more;till after 0.73MaBP

the 100ka cycle has become predominant.The loess record in our country has also revealed the similar result

and show that the climate has modificated greatly since tertiary

which maybe closely related to the pulsating uplifts of the Tibet plateau.