Quaternary influx of proximal coarse-grained dust altered circum-Mediterranean soil productivity and impacted early human culture

Abstract

Amit et al. (2021) propose that grains of coarse silt-sized quartz in soils of the southern Levant originate from long-term Pleistocene abrasion of silt-sized quartz particles from moving dune sand, such as in the Sinai-Negev dune field, Israel, and related loess deposits (Crouvi et al., 2008). Their article attempts to muster additional support for this theory by constructing a narrative employing archaeology and land use history as witnesses of the role of silt-sized quartz grains for soil productivity and the emergence of civilizations in the southern Levant. According to this hypothesis, the construction of ancient agricultural terraces was bound to sufficient hilltop soil cover, whereas away from desert quartz sources, e.g. in the Galilee and in Crete, soils were too thin for this practice. Thus, Lebanon should not host such terraces due to a lack of coarse quartz silt, but, in fact, terraces remains cover ~7% of her territory (Masri et al., 2002). Crete is also not devoid of terrace remains (Orengo and Knappett, 2018) and they are abundant in nearby islands (Bevan et al., 2013). Ancient terrace construction did not depend on sufficiently deep hilltop soils: research at Petra in Jordan demonstrated that Nabatean runoff-irrigated terraces harvested not only water, but also aeolian sediments, thus creating fertile soils on previously barren rocks (Lucke et al., 2019). Moreover, agriculture has been practiced on various soils of the southern Levant, favorably on colluvial soils of local depressions (Singer, 2007).