The first crack of the, well, shell.

I decided to start up this blog for largely selfish reasons. The task ahead is so daunting and exciting that I wanted to have a record of how everything goes down. I'm an archaeologist coming from an unequivocally humanities-based training (to which I attach no shame...) who specialises in shells, and things made from shells, excavated from archaeological sites. I work mainly in Southeast Asia and the Pacific Islands; two places where shells reign supreme.

I've just started a 5-year research fellowship looking at the nitty-gritty of how to recognise and interpret artefacts produced in shell. I'm not talking about the beads and bangles of the last few thousand years here. I'm talking about early Homo sapiens 20,000 - 50,000 years ago, and even earlier species of hominid, bashing up a shell, or simply using a whole one, to get things done. For the sort of time periods I'm looking at, people most often think about stone tools, or maybe in some parts of the world bone and antler. But in Southeast Asia and the Pacific there are over 10,000 species of shell, and from our minuscule insights to date, we know that ancient peoples were using them.

The catch is (there's always a catch) that we as archaeologists understand so little about shell as a raw material, that we can't accurately (or at least convincingly) distinguish between a shell that's been 'worked' (i.e. modified by humans), from one that's been dropped, stood on, or modified by a whole range of natural chemicals and greeblies that hang about archaeological sites. This is all complicated by the fact that different shell families have different compositions, and all the tiny calcium carbonate crystals that make up a shell are patterned in a whole lot of different ways. This means that if you bash a cowrie shell with a rock, it's going to break differently from a limpet you bash with the same rock. It also means that those greeblies and chemicals will act upon its structure differently. Generalisation about 'shell' is a no no. This is where my project comes in....

I am now charged with the intimidating task of taking 12 different types of shell, and systematically looking at how they break. For non-engineers (such as myself) this is called fracture mechanics. I need to look at how whole shells breaks so we can 'read' fragments that we recover from archaeological sites correctly. Then, I need to put all the edges under a super-fancy microscope (called a Scanning Electon Microscope or SEM) to get up close and personal to the crystals so that we can read fractured edges at the microlevel. For non-engineers, this is called fractography.

After looking at how these shells fracture under ordinary mundane circumstances, I then move on to how to detect traces of human modification. This will entail a whole lot experimental work, cutting and busting shells in different ways, and checking out the results with the SEM.

All of this (and more) will come together to produce a blueprint for detecting human use and modification of shells. We should then be able to look at a fractured edge under a microscope and have a pretty good idea how that break happened and whether a human was responsible. Yay!

If all that seemed more-or-less straightforward, here's why it's not. To do this project requires delving into a whole lot of disciplines; some of whom talk to each other and some of whom don't. There's engineering (mechanical and civil), materials science, biogeochemistry, palaeontology, structural biology and brain-melting amounts of general physics. Not the sort of stuff you ordinarily learn within an Arts degree.

So ... this blog will be the ongoing trials, tribulations, successes (hopefully some) and failures (undoubtedly many) of my mission to answer the questions of my research. Over the coming months, I will be enlisting the help of engineers, geochemists, structural biologists and crystallographers (they're special chemistry people) to get the job done. I will be wading through journals whose names I have to think about to pronounce and night-schooling myself in quantum physics. Through all of this, I will be earnestly trying not to make too big a fool of myself in front of learned professors and absorb all this new world has to offer. So, hang onto your hats, and welcome to the heady world of research.