The Soan Valley: stone tools, sediments and dating

Tools in a changing landscape

The Soan Valley’s prehistoric record includes finds in several kinds of geological setting. A University of Exeter account by researchers Linda Hurcombe and Robin Dennell describes fieldwork undertaken with Pakistani colleagues from 1987. At Riwat, it reports stone tools within a conglomerate dated to more than two million years ago. That is the project’s account of a particular deposit and assemblage, rather than a date for everything found near the modern settlement.[1]

The same account distinguishes the Pabbi Hills, where erosion exposes soft river sediments and fossil-rich layers, with simple stone tools sparsely distributed on the surface. Tools embedded in a deposit and objects collected from an eroding surface raise different questions about context. Keeping those situations separate is essential before combining them into a regional chronology.[1]

What the Potwar loess study measured

A 2020 study by Yorinao Shitaoka, Atsushi Noguchi and Muhammad Zahir revisited the chronology of Potwar loess using optically stimulated luminescence. The authors measured quartz extracted from sediment, comparing this approach with an earlier thermoluminescence framework. Their published abstract reports ages between 15,000 and 80,000 years. These figures concern the sampled sediments; they are not a new date for the much older Riwat conglomerate.[2]

The authors state that their results support earlier thermoluminescence estimates. The useful lesson is the relationship between sample and conclusion: identify the sediment being measured, the dating method and the archaeological context it helps constrain. Combining every numerical result under a single label such as ‘Soan age’ would erase the very distinctions the investigation was designed to establish.[2]

Why a valley is not one site

Dennell’s earlier Siwalik synthesis emphasises the movement and deformation of river deposits during Himalayan mountain building. The valley must therefore be read as a changing geological landscape containing archaeological evidence, rather than as one undisturbed occupation floor or one continuous settlement.[3]