An investigation of local scale human/landscape dynamics in the endorheic alluvial fan of the Murghab River, Turkmenistan

Endorheic or inland deltas, commonly found across the deserts of Central Asia, represent unique and dynamic ecotones that are still not fully understood. These regions of environmental and landscape transition as well as social liminality straddle the line between fertile, sustainable environments and less productive desertic regions less capable of sustaining significant human occupation. Because such boundary areas are dynamic and often unpredictable, they are excellent case studies through which to study the complex processes that have characterized human/environmental relationships throughout the late Holocene. This paper focuses on the local variability that characterizes these relationships in one such region, the terminal fan of the Murghab River in Turkmenistan. Populated since at least the late 5th millennium BP and likely earlier, the region has been variously described as an oasis environment in which desertic processes have been more or less stagnant throughout the late Holocene, or, alternatively, as a fertile, continuously occupied and heavily-cultivated alluvial fan in which desertification was a relatively late process, intensifying only in the mid 4th millennium BP. This paper presents geoarchaeological data from a series of test pits in the distal portion of the terminal fan to show that local-scale analysis indicates a far more complex interpretation, one shaped by the continuous and non-uniform interaction of aeolian and alluvial depositional environments, and one that bears substantially on human/landscape dynamics in the region. The late Holocene development of the distal fan is examined using proxy data from granulometric analysis, Loss on Ignition (LoI) and geochemical analysis, as well as a series of new OSL dates that refines the depositional chronology of the region. Ultimately, we show that landscape change throughout the Holocene has been characterized by pronounced variability at the local level not fully described by regional scale approaches. While differential aeolian encroachment, non-uniform alluvial processes, and climatic conditions bear significantly on the initial conditions for human occupation, human/environmental processes are ultimately co-evolutionary in nature