Reconstructing Early Pleistocene (1.3 Ma) terrestrial environmental change in western Anatolia: Did it drive fluvial terrace formation?

A terrestrial environmental reconstruction of an Early Pleistocene landscape from western Anatolia is presented. The basis of this reconstruction is a sedimentary stack comprising fluvial and colluvial slope deposits. Contained within this stack is a sequence comprising two massive laminar calcretes alternating with three reddish palaeosols. This evolutionary sequence is situated on top of a fluvial terrace staircase capped by a 1.3 Ma (40Ar/39Ar plateau age) lava flow. The micro-morphological properties of the observed calcretes and reddish palaeosols combined with the stable oxygen and carbon isotopic composition of the carbonates suggest the alternation of three stable relatively warm–humid (vegetation rich) and two stable relatively arid–cool (bare surface) cycles. In addition, there is also ample evidence for landscape instability in between these phases causing local soil truncation and slope instability in an open grassland–shrub environment. These landscape instability phases match well with known fluvial incisional phases of the Gediz during this period. This suggests that climate-forced landscape environmental dynamics were of sufficient magnitude to drive fluvial terrace formation of the Early Pleistocene Gediz.