Simon Armitage graduated with a BA in Geography at the University of Oxford before moving to the University of Wales Aberystwyth to research his PhD entitled “Testing and application of luminescence techniques using sediment from the southeast African coast” under the supervision of Prof. Ann Wintle and Prof. Geoff Duller. He finished his PhD and moved back to Oxford where he was employed for four years as a postdoctoral researcher on two NERC funded projects. Simon was appointed Lecturer in Physical Geography at Royal Holloway in 2006.

Geomorphology, climate and archaeology of Africa and the Arabian Peninsula

My research focusses on long-term landscape evolution, palaeoclimatic reconstruction and human-environment interactions in prehistoric societies in African and Arabian drylands over the last ~half million years. This work is conducted using a combination of extensive fieldwork, often in remote locations and as part of an interdisciplinary team, and rigorous laboratory analysis at the Royal Holloway luminescence dating facility, which I direct. There are four main themes within my research. 

• Long-term landscape change in present-day drylands.

Initially my work focused on identifying geomorphic evidence for the expansion and contraction of the Sahara, by studying sediments deposited by large but relatively short-lived lakes (palaeolakes). Luminescence dating of these sediments allowed the identification of repeated, pronounced interglacial wetting of present-day deserts, facilitating human and hominin population movements. On a shorter timescale, dating shorelines in Nigeria and Chad provided a detailed Holocene lake-level history for Palaeolake Chad, which was once the largest water body in Africa, and is now its largest dust source. My work on prehistoric population movement builds upon the concept that northern hemisphere deserts experience episodic wetting, which facilitates hominin dispersal out of, and back into Africa. For example, my research suggested an unexpectedly early arrival of modern humans in Arabia (at Jebel Faya, UAE), explained by a simultaneous narrowing of the Bab el Mandeb Straits and climatic amelioration in eastern Africa and Arabia during the last interglacial. My more recent work in Arabia has focused on reconstructing landscape evolution in the Nefud Desert of central Saudi Arabia, by dating the patchwork of fluvial and lacustrine deposits preserved there. This work favours a terrestrial dispersal route via north Africa and the Levant, but demonstrates the occurrence of not one but several, climatically modulated hominin dispersals into Arabia over the last 400,000. I have also studied dune mobility history in the Sahara and South America.

• Coastal dune emplacement in southern Africa.

I did not initially pursue this theme after my PhD. However, as part of my work with the SapienCE Center of Excellence in Bergen (SapienCE), my postdoc Dr Ella Walsh is using a range of evidence, including luminescence dating of key units, to reconstruct the coastal landscape evolution at Klipdrift and Blombos archaeological sites. In both locations, repeated cycles of dune emplacement, stability and erosion are evident.

• Dating of palaeolithic archaeological sites.

Accurate and precise chronologies for palaeolithic archaeological sites are critical to understanding both human-environment interactions and for comparing archaeological records between sites. My work on dating palaoelithic sites has involved both dating individual events, such as the earliest human burial in Africa, at Panga ya Saidi, Kenya and the (then) earliest evidence of humans outside of Africa at Jebel Faya, UAE, or the ongoing construction of chronologies for longer archaeological sequences such as at Varsche Rivier 003 in South Africa. In the latter case, we were able to demonstrate that shifts between summer and winter dominated rainfall regimes in southern Namaqualand led to episodic isolation and merging of ancient populations.

• Dating long terrestrial and ocean records.

I am also interested in dating long lake and ocean sediment cores, especially those which provide detailed African palaeoclimate records. These records are difficult to date beyond the range of radiocarbon dating without tuning to a climate proxy, which risks circular reasoning and potentially obscures important leads/lags, hampering their use for palaeoclimatic reconstruction. For example, prior to my work with Dr Laura Streib (then at Syracuse University) on material from Lake Malawi, at least three separate, but mutually exclusive age models for the core existed. Using state-of-the art luminescence techniques, we directly dated the youngest 500 thousand years of the core, allowing more confident interpretation of the detailed palaeoclimatic record from Lake Malawi. Going forward, I am working on two Indian Ocean cores drilled for SapienCE and am involved in two International Continental Scientific Drilling Program (ICDP) projects aiming to core Lake Victoria and Lake Kinneret (Sea of Galilee, Israel).

Luminescence dating

My main tool for geographical research is luminescence dating of sedimentary quartz and feldspar. Over the last two decades the single-aliquot regenerative dose technique has led to significant decreases in the uncertainties associated with lumienscence ages, but these improvements have led to the identification of additional sources of error which were previously of negligible importance. My research into the luminescence properties of quartz and feldspar has been driven by the requirement to enhance the credibility of ages generated as part of my ongoing interests in geomorphololgy, climate change and archaeology. This has led to research into the generation of accurate ages for sediments from challenging environments such as the deep ocean, long palaeoclimate sequences (e.g. Lakes Malawi and Bosumtwi), African/Arabian palaeolakes and palaeolithic archaeological sites.