Geoarchaeological and palaeoenvironmental interpretation of residual hills and relict slopes in the Central Ebro Basin, Spain

Abstract

The cyclical evolution of the testimonial buttes in the central area of the Ebro depression (Los Monegros) is analysed. It is a semiarid environment that favours high erosive rates. The aim of this paper is to obtain an evolutionary model of the Jubierre hills that shows the environmental cycles represented by aggradational and degradative processes on the slopes that produced the present arrangement of talus flatiron rings. In the four studied cases, the talus relicts are composed of detritic material from a disappeared caprock pediment. Four slope stages (S4 to S1) formed under more stable climate conditions are identified. Older stages ages (S4 and S3) are estimated by comparison with other talus flatiron systems from the region. The S2 stage contains Bronze Age archaeological remains and the radiocarbon age obtained was 1608 − 1446 years cal BC (2σ), while S1 is younger. A climate genesis is established for these aggradational stages (S4 to S1). The active erosion of these hills led to a relief inversion and talus flatirons remain as the only features revealing the presence of the old hills and past human occupations.