INVESTIGATING THE NATURE AND TIMING OF THE EARLIEST HUMAN OCCUPATION OF NORTH AMERICA USING A NOVEL INTEGRATION OF BIOGEOCHEMISTRY AND MICROMORPHOLOGY

How, when and why did people first arrive and settle in the Americas? This puzzle is one that has captured scientific and public imagination, and is the subject of continued debate. The traditional model of 'Clovis First' asserts that the Clovis culture, named after their distinctive stone tools found near Clovis, New Mexico, in the 1920s and 1930s, arrived on the continent around 13,500 BP. These people would have travelled across the Beringia land bridge in Siberia, during a time when sea levels were lowered during the last ice age, and eventually made their way south on the east side of the Rocky Mountains. Recently a growing body of evidence points to a more complex process, with perhaps several waves of migration of different cultural groups. This has led to a situation where there is no consensus on how humans first came to the Americas. The main barrier to addressing this debate, is the scarcity of well-preserved sites and easily datable materials, where we can be sure that what we are dating really does represent human presence. Human skeletal remains from this period are especially rare, and also incredibly difficult to study due to restrictions of the Native American Graves Protection and Repatriation Act 1990 (NAGPRA). However, a more unusual form of archaeological evidence are well preserved in caves: fossilized human faeces, or coprolites. One of the most famous prehistoric coprolites, is a specimen from Paisley Caves, Oregon, dated 14,300 BP; one thousand years earlier than evidence from the Clovis culture. This coprolite is strong evidence for the 'Pre-Clovis' occupation of North America. The coprolite was identified as human on the basis of ancient DNA, but there have been debates over the stratigraphic integrity. This is a problem which continues to underlie much research in this area. We simply do not know the extent to which these molecules are mobile within cave sediments. This is the missing scientific link which prevents the coprolites from being used, unambiguously, to confirm the pre-Clovis hypothesis and solve this long running debate. Our research will make a first attempt to address these problems, by using a novel integration of biogeochemistry and sediment micromorphology - a method successfully developed by the PI and Co-I. Sediment micromorphology can be thought of as an excavation under the microscope. Intact blocks of archaeological sediments are set in resin and turned into slides for viewing under a microscope. This way we can visually examine the processes by which sediments have been deposited, and whether they have been subsequently altered. Combining this with biogeochemical analysis of faecal lipids will enable us to quantify the extent to which these molecules move from their point of deposition . We will conduct this analysis in conjunction with radiocarbon dating of specific chemical fractions - rather than dating all the organic material in a sample, we will date individual chemical fractions within the coprolites. This way we can provide a firm species identification, and simultaneously an unambiguous date for when the coprolite was deposited. Whoever these early settlers were, these unlikely sources of evidence that they left behind contain a wealth of information which we can now access using the novel techniques proposed in this research project. Once we can demonstrate the integrity of the coprolite materials found in the cave and therefore have confidence in the scientific data we obtain from them, we can use the molecules and fossils preserved with the coprolites to reconstruct the diets of these individuals, and the environment they inhabited. By linking this with high resolution radiocarbon dating, we can begin to extend the research potential to look at other questions of scientific and archaeological interest such as the seasonality of cave use; what relationship did these early settlers have with the environment, and how did they utilise the resources available to them?

We have identified members of the public, school children and avocational archaeologists as non-academic beneficiaries and more specifically, due to the location of the field site, the state of Oregon (Parks and Recreation Department). The public, including school children, in both the North East UK (where the research is based) and in Oregon (where our case study is based) have a keen interest in heritage and archaeology, evidenced by multiple amateur organisations such as the Northumberland Archaeology Society, and the Archaeological Society of Central Oregon, and frequent archaeological based activities with Tyne and Wear Archives and Museums. More generally, there has been a growing global interest in so-called Palaeo or Palaeolithic Diets, a celebrity diet based on the types of foods presumed to have been eaten by early humans. Whilst the science behind the diet has been debunked (e.g. by the British Dietetic Association), it is still growing in popularity (Innova Market Insights, a food and drink product development tracking tool, has seen a surge in the use of the word paleo in 2015, and the PaleoFX conference attracts thousands of visitors each year). Coprolites are a novel way of understanding ancient diet, and can be used as a tool to educate people about what 'real' prehistoric diet was like. People can directly relate to and understand fossilised faeces, and there is a fascination with how we can use these 'unusual' materials to understand people in the past. For our immediate impact plan, we propose a joint UK and US exhibition, with the Great North Museum: Hancock (Newcastle), and the Oregon Museum of Natural and Cultural History, that focuses on how geoscience and chemistry are being used with archaeology to understand prehistory and palaeodiet. This will be accompanied by a series of talks by the PI and PDRAs, which will be filmed. We will use this opportunity to develop a long-lasting relationship with the museums and help them increase their profile. The PI is an experienced user of social media, with a long running established blog (http://castlesandcoprolites.blogspot.co.uk/). The project progress and impact activities will be documented on the blog, with videos being circulated on social media to reach a wider audience. We will also link with international blogging events such as the Day of Archaeology (http://www.dayofarchaeology.com/paisley-caves-a-view-from-the-microscope/), and the Festival of Archaeology.
Focusing specifically on school children, we will develop and run activities using archaeology to communicate concepts in chemistry and biology, linked to Key Stage 3 and 4 of the National Curriculum (chromatography; plant structure; diet), at the Edinburgh International Science Festival and Oregon Archaeology Society Roadshow. The PI has professional links with Tyne and Wear Archives and Museums (TWAM), and has designed similar activities with them on an informal basis ('Make Your Own Coprolite'). TWAM is supported by the five local authorities of the area and Newcastle University, and has Core Funded Museum status. The resources we develop will be uploaded to upload to Newcastle University's Teachers' Toolkit website (http://toolkit.ncl.ac.uk/search-toolkit/subject/archaeology-70). A longer term plan is to develop professional teaching resources in addition to the festival/museum activities. We plan to apply for NERC Follow On funding in October 2018 to develop this aspect of our impact plan, to produce a wider range of visual aids including short videos and animations, in consultation with the National STEM Center and North Tyneside Learning Trust, which will make these materials available to a wider audience across the UK.