Fieldwork Overview

Since 2014, I have been conducting archaeological fieldwork in Tanzania at Oldupai Gorge, Singida, and the Usambara Mountains. Previously, I worked at an Acheulean site in eastern Zimbabwe called Maunganidze that contains a wealth of large prepared cores, blanks, and large cutting tools that illustrate diversity and complexity in stone reduction. The nearest comparative baseline of these stone tools is actually found 1300 km to the southwest in what is known as Victoria West from South Africa. The site of Maunganidze actually represents the first Acheulean locus situated along the transitional ecoregion that links southern, central, and eastern Africa.

In China, I worked at the Neolithic Tianluoshan site, where some of the earliest evidence of rice farming in the country is found. The Tianluoshan archaeological site is located in Zhejiang Province, at the edge of the Ningshao Plain in the Yangtze Delta, and contains two incidences of rice farming that occurred between 7.0 and 6.4 thousand years ago (the early rice farming period) and then reemerged and flourished between 6.3 and 4.6 thousand years ago (the later rice farming period). I am working on other projects in China that involve environmental reconstructions using plant remains from the Great Wall as a paleo-proxy, the production and transportation of silk, and the environmental context of the Lantian and Nihewan Basins.

I have also done non-archaeological fieldwork on the island of San Salvador in the Bahamas and at Clarkia, Idaho, USA. On San Salvador, for my masters thesis, I focused on groundwater geochemistry and microbiology and how different biogeochemical processes play significant roles in the dissolution of carbonate rocks and the eventual formation of “Black Hole” vertical cave systems. At Clarkia, which is known for its extraordinary preservation of Miocene-aged fossils, I assisted in collecting plant fossils that are so well-preserved that ancient biomolecules were studied using different analytical chemistry techniques as if they were modern plants. We are now using lake sediments from Clarkia as correlates for ancient lake environments of Mars to study organic preservation and the potential of identifying past life on the Red Planet.

Fieldwork & Archaeological Biomarkers

Much of my research can be broadly defined as the development of 'on-site' isotopic records of human-environment interaction from archaeological- and hominin-bearing sediments. Mainly, I am interested in paleoenvironmental proxies of immediate relevance to the archaeological record, and use biogeochemical methods, such as plant wax biomarker stable isotopes, to provide detailed insight into vegetation change, precipitation patterns, biodiversity, and other paleoclimatological and paleoecological conditions. However, while this research theme has been applied in archaeology and paleoanthropology, records often remain at some distance from archaeological sites of interest.

The interest in molecular fingerprinting plant biomarkers in archaeological and paleoanthropological studies, lies in key advantages this technique holds over other proxies. Plant wax carbon isotopes are not biased toward herbivore feeding behavior like that of tooth enamel, and lipid biomarkers are more widespread than paleosol carbonates, which only form in soils where annual rainfall is less than 1,000 mm per year. Pedogenic carbonates cannot capture short-term climatic and environmental variability like that recorded in plant waxes because of slow formation processes. While phytoliths track the boundary between woodlands and grasslands, they cannot reliably identify photosynthetic pathways like plant wax isotopes. The production and dispersal of pollen varies widely between different plant families and genera, and preservation is contingent on anoxic conditions and other parameters. Because of this, well-preserved pollen-bearing sediments are scarce within non-maritime, specifically arid or semi-arid, regions such as what we have in eastern Africa. Compound-specific isotope analyses on individual biomarkers also erases the ambiguity in isotope measurements inherent in bulk sediment isotope analysis.

Now of course plant wax biomarkers have their own interpretive challenges, and ideally, plant waxes should be studied along with pollen and phytoliths to calibrate interpretive biases stemming from differential wax production and biomarker transport histories. When they are reported together, pollen, phytoliths, faunal isotopes, and biomarker isotopes can efficiently detect shifts in C3/C4 vegetation, plant community structure, and (intra)biome diversity at high resolution. I work with some truly amazing colleagues who specialize in phytoliths, pollen, and tooth enamel carbonate isotopes, and this collaboration allows us to generate well-integrated, high-resolution datasets to understand past ecosystem response to climate variability, and hominin behavioral, morphological, and technological adaptations to complex environmental and ecological change.