ABSTRACT
RIVERTERRACES53 ansmgofbase-level,itbuildsuporaggradesitsbed.
Terraceswereformedinthelowerreachesofriversduring Pleistocenetimesmainlyasaresultoftheoscillationofsealevelconsequentontheperiodicwithdrawalofwaterfromthe oceansasice-sheetsgrewonland.Thus,duringtheglacial maxima,whentherewasregressionofthesea,therivers activelyerodedtheirbedsinresponsetotheloweredbase-level. Thedown-cuttingbeganattheirmouthsandworkedupstream. Duringinterglacialswhensea-levelwasrisingagain,therivers becamesluggish,siltedupthenewchannelsandbuiltthick depositsontheirvalleyfloors-theprocessknownasaggradation.Althoughchangesinsea-levelarenotimmediately registeredintheuppercoursesofrivers,the'headofrejuvenation'58duetoeachfallinbase-levelgraduallytravelsupstream.
