A Quaternary soil chronosequence of Southeastern Spain

A Quaternary soil chronosequence of the Aguas river terraces has been estab lished, and it seems to be typical for the Vera basin. The chronology of th e fluvial sequence of 15 geomorphological units was determined by geomorpho logic and sedimentologic criteria, C-14, Pb-210, U/Th disequilibrium dating and artifacts. The data indicate that Rhodoxeralfs (Red Mediterranean soil s) formed during early Pleistocene, Haploxeralfs (reddish Mediterranean soi ls) from the middle Pleistocene to isotopic stage 5, and weak developed soi ls (e.g. Haploxerolls) during late Pleistocene and Holocene. In particular, the Bt horizons of the Rhodoxeralfs are decalcified, show a redness rating of 15, have high Fe and Al contents and degraded cutans and overlie thick nodular and/or laminar Bk horizons. The younger soils are thinner, redness rating and the content of cutans in the Bt horizons less. The youngest Hapl oxeralfs are associated with the fluvial terrace T3 overlyed by travertine deposits dated at 148,000 +/- 8000 yr B. P. (U/Th), and on the last intergl acial marine terrace located at +9 m a.s.l. In adition to the 148,000 +/- 8 000 vr B. P. (U/Th) travertine phase, the main period of travertine formati on have been detected between 94,000 +/- 5000 and 54,000 +/- 2000 vr B. P.( U/Th), and were drastically reduced during isotopic stage 2 and the Holocen e. The environmental conditions seem to be too dry for an intense soil and travertine development during these latter periods.