Portable OSL supported OSL-dating of sediment accumulation and agricultural hinterland development in the southwestern Jerusalem Highlands, Israel

Portable (port-) OSL profiling and absolute OSL dating enables relative and absolute age acquisition of dry agricultural terrace sediment fill that is understood to usually reflect the age of terrace construction. Here we coupled 300+ port-OSL measurements in 30+ profiles with 12 OSL ages to date archaeological agricultural installations (wadi and slope agricultural terraces, roads, walls, rock piles) and an adjacent, well-preserved type-section of clast and fine-sediment accumulation in a non-terraced, 1^st-order basin depression. The study region around Mevo Betar, in the southwestern Jerusalem Highlands of Judea, Israel, consists of mixed Terra-Rossa (Red Mediterranean) soil between lapies formations, in a small-spring dominated, Mediterranean, hard carbonate terrain. The region underwent fluctuations in agricultural-oriented village occupations since Chalcolithic times.

The Terra Rossa soil-like sediment accumulating in the 1^st-order  depression since Epipalaeolithic (~17-13 ka) times yields a reliable (R²=0.96) port-OSL – OSL linear regression, that in turn can help roughly estimate ages of the sediment of nearby port-OSL profiled agriculture installations. These installations yield OSL ages dating to Roman, Byzantine, Late Islamic and mid-Ottoman times with limited remains of earlier preserved and presumably natural, aeolian source-sediment of the soils.

It appears that wall-lined agricultural roads and terraces were implemented in Roman to Byzantine times, with a 2^nd major phase of expansion in the last millennium, the latter well-established chronologically for terraced hinterlands in the northern Jerusalem Highlands (Porat et al., 2019; Ben-Melech et al., 2025). A distinct dam-like wall dissecting the depression, roughly age-estimated by the port-OSL-OSL regression to Roman times, may be further evidence of Roman involvement, as recognized by another Roman-dated wall dissecting a nearby wadi.

Despite no significant increase in aeolian dustfall since ~2.5 ka, average sediment accumulation rates in the 1^st-order  depression grew threefold, probably due to anthropogenic soil exposure by agriculture, grazing and shrub/tree utilization for fire fuel. Such enhanced soil erosion may have been observed by locals, and eventually motivated terracing efforts. We suggest that the expansion of agricultural installations into hinterlands of ancient villages in the southern Levant was characterized by a non-linear growth process that included improvement and maintenance of existing features, and a generally radial development pattern from village peripheries into "terra incognita" hinterlands over a wide range of hard carbonate formations and morphologies. This expansion led to the current landscape morphology with significant terrace cover, that still constrains erosive slope processes.

 

Porat, N. et al. (2019). Using portable OSL reader to obtain a time scale for soil accumulation and erosion in archaeological terraces, the Judean Highlands, Israel. QG, 49, 65-70.‏

Ben-Melech, N. et al. (2025). Agricultural Terracing and land tenure in late medieval Southern levant: the case of Nahal Ein Karim, Jerusalem. EA 30(6), 590-604.‏