Incoming solar irradiance ultimately governs the amount of energy within the Earth’s system. Our understanding of how solar irradiance is modulated by the Earth’s orbital pathway underpins our understanding of long-term (>10,000 year) global climate and vegetation change through the geological record. However, there is no independent long-term record empirical record of solar irradiance on timescales >10,000 years. This project generate the first record of solar irradiance change at the Earth’s surface by applying cutting-edge organic geochemical techniques to a unique tropical record of past vegetation change.
This work involves collaboration with other leading researchers : Dr Will Gosling (The Open University), Dr Barry Lomax (University of Nottingham), and a number of key research institutions: Imperial College London, University of Oxford, University of Texas, and the Forestry Research Institute of Ghana. In addition, this project will have a Postdoctoral Researcher and a PhD student working on closely-related areas of reserach.
Palaeolake sequences offer considerable potential for generating high-quality palaeoenvironmental data in arid environmental settings. Such deposits are often characterised by high rates of sedimentation, potentially resulting in continuous records that are highly resolved in time and respond rapidly to external forcing. Significantly, palaeolake basins are widely distributed throughout south-east Arabia.
For his doctoral research Gareth conducted a high-resolution, multi-proxy examination of two palaeolake sediment sequences in the Emirate of Ra’s al-Khaimah, UAE: Awafi and Wahalah. The data revealed that climate has varied greatly between ~8500 – 4200 cal. yr BP, with periods during which conditions were more pluvial than the present punctuated by phases of intense aridity. Furthermore, the work suggested that abrupt increases in aridity recorded in the palaeolake sediments between ~8000 – 7800 cal. yr BP, from ~5900 cal. yr BP and at ~4200 cal. yr BP, reflect the response of the regional landscape to global climatic variations.
Future work will include the examination of the particle size distribution of the sedimentary records at both sites. In addition, it is hoped to obtain further Optically Stimulated Luminescence (OSL) dates from the Wahalah record and thereby strengthen the chronological framework at the site.
Originally discovered in the early 1990s, Umm al-Quwain 2 (UAQ2), Emirate of Umm al-Quwain, UAE, is currently being re-excavated by archaeologist Dr Sophie Méry (CNRS) and her team. The site lies close to present coastline on the crest of a Late Pleistocene dune which rises over 10 m above the surrounding sabkha. The repeated use of the site is attested by the presence of a series of stratified shell middens which cap the sterile dune sands and have been dated to the 5th and late 4th Millennium BC. UAQ2 is thus one of a number of Neolithic shell middens reported from along the coastal desert region of the southern Arabian Gulf. Significantly, however, the shell horizons overlie a Neolithic cemetery, from which the skeletal remains of at least 45 individuals have been recorded to date. The site, therefore, forms the second largest Neolithic cemetery in the region after Jebel al-Buhais 18.
These sediments are currently being analysed in order to develop an understanding of the environmental processes operating at the site at the time of Neolithic occupation. In particular it is hoped to determine how the repeated phases of human occupation fit within the broader framework of regional climatic and environmental change currently being developed for the region (see Holocene Palaeolakes – Awafi and Wahalah).
Jebel Faya, UAE, is a key site for understanding the migration of anatomically modern humans (AMH) Out of Africa. Archaeological excavation, under the direction of Professor Hans Peter-Uerpmann (University of Tübingen, Germany), has yielded Palaeolithic finds which can be dated as far back as 125,000 cal. yr BP. Significantly Armitage et al. (2011) propose that these finds have affinities to the late Middle Stone Age in northeast Africa, indicating that AMH may have a migrated into Arabia via a southern route (across the Red Sea at the Bab al-Mandab Straits) at beginning of the last interglacial (Marine Isotope Stage 5e), a time of significantly lowered global sea levels and intensified monsoonal rainfall throughout southern Arabia. The subsequent expansion and contraction of human populations throughout Arabia during the following 100,000 years is suggested to have been closely tied to the prevailing climatic conditions.
An international team of scientists – including Professor Adrian Parker from Oxford Brookes University – have revealed that humans left Africa at least 50,000 years earlier than previously suggested and were, in fact, present in eastern Arabia as early as 125,000 years ago.
These ‘anatomically modern’ humans – you and me – had evolved in Africa about 200,000 years ago and subsequently populated the rest of the world.
The new study published in the journal Science reports findings from an eight-year archaeological excavation at a site called Jebel Faya in the United Arab Emirates.
The direct route from east Africa to Jebel Faya crosses the southern Red Sea. Professor Parker studied sea-level and climate change records for the region and concluded the direct migration route may have been passable for brief periods in the past. During Ice Ages, large amounts of water are stored as ice, causing global sea-levels to fall. At these times, the seaway of the southern Red Sea narrows considerably, making it easier to cross.
“There was a brief period where modern humans may have been able to use the direct route from east Africa to Jebel Faya,” said Professor Parker.
Palaeolithic stone tools found at the Jebel Faya were similar to tools produced by early modern humans in east Africa, but very different from those produced to the north, in the Levant and the mountains of Iran. This suggested early modern humans migrated into Arabia directly from Africa and not via the Nile Valley and the Near East as is usually suggested.
The new findings will reinvigorate the debate about man’s origins and how we became a global species.