From identifying a dismembered body to investigating Bronze-Age decking, it's all in a day's work for environmental archaeologist Nick Branch. Chris Bunting reports

When Nick Branch is on his favourite subject, you half expect him to throw up his arms and deliver, with the ease of a full-throated Welsh tenor, a rousing chorus of "Mud, Mud, Glorious Mud! There's nothing quite like it for cooling the blood. So, follow me, follow, down to the hollow, And there let us wallow in glorious mud." Branch has oodles of the stuff. Bags, buckets, tubes, trays, boxes and sacks of it fill his labs at Royal Holloway, University of London. He sieves it, sorts it, refrigerates it, waters it, dunks it in an array of chemicals, cuts it and, sometimes, just looks at it for hours in its original state. Sand is not really his thing, although he has been known to dabble. A bit boring, he says: not enough in it. Gravel can be a bit more promising. But mud sets his heart pumping. He is a mudlark of a very modern sort.

"It is surprising what you can get from a bit of mud," says the environmental archaeologist, proffering yet another bucket of the brown stuff. Branch will set up the country's first undergraduate degree in geography with environmental archaeology at Holloway next year, teaching students the techniques and methods of analysis through which mud and other apparently unpromising organic and inorganic materials can yield detailed information about geographic environments.

"I have just been working on a case this morning that has been brought to us by the police. Someone stowed away in a plane coming from an African country and died in the cargo hold," Branch explains. "The problem is that the plane stopped off in several different places and we don't know where he got on or where he comes from. But we have got mud from his shoes. We have gone and got samples from the airport grounds where the plane took off. If we can get a match we can start to trace him."

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A less muddy but more complex investigation he is working on for the police involves algae, pollen and mineral remains. He is trying to find out about an African boy, whose dismembered body was found in the Thames last year, after what is suspected to have been a "muti" ritualistic killing.

"We can look at the algae that have been deposited in the body to say whether it was placed in the estuary, a predominantly marine environment, or much further up the river in a fresh water environment. What we have found suggests that he was placed in a tidal environment where you have both types mixing, somewhere near the sea but not beyond Teddington lock, where you might expect more of a marine signature," Branch says.

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"We are also looking for geographical information about the boy's origin. He was a young black boy but was he from the Caribbean, Africa or the UK?

"Only the torso was found, so there is little evidence. The work that we have done looking at the pollen in the large intestine has shown that he was alive in the London area within 72-hours of when he died. The pollen has become incorporated in food material that has been ingested and we can identify its origin.

"But his DNA shows us quite conclusively that he is West African in origin. Looking at the chemical composition of his bones tells us, for instance, whether plants have been grown or animals are grazing in areas with a particular geology. Within the boy's intestinal contents, we have also found a mineral material that is quite specific to certain parts of Africa. We have narrowed it down to three countries and it looks more than likely that it is going to be Nigeria. What the police are doing now is going there and collecting samples from domesticated and wild animals and from soils."

This kind of detective work is also used in the more familiar context of archaeological digs, where pollen spores, algae, snail shells, insect remains, charcoals and seeds found in the mud surrounding a site can often tell as much about our ancestors' lives as can more glamorous artefacts.

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A project near Woolwich in North London is looking at a Bronze-Age wooden trackway. "It is a beautiful construction, between 3,000 and 4,000 years old," Branch says. "Wood wattling has been built up and there are planks going across the top of it allowing people to cross an area of marshland from higher ground and, perhaps, giving them access to resources such as fish, birdlife and the river itself.

"Right next to it we have got a 5m 2 wooden platform, also beautifully constructed. We have no idea of its function. What we will be able to do now is take samples from peat that is contemporaneous with the trackway as well as above and below it. We will look at insect remains and, using maps we have of insect populations in various temperatures, say specifically what the climate was like during, before and after this time. We will use pollen and other remains to say what the vegetation was like in the area, not only what was growing on the wetland, such as alder trees, but also what was growing on the dry land - whether, for example, cereals were cultivated.

"We want to try to establish when these people occupied this area, how long they were there and why they abandoned it. What happened? Did the water suddenly rise, did the temperature change? You begin to build up quite a detailed picture of the world around this trackway, how people lived, what happened to them."

Branch, who took an archaeology degree and MSc at University College London before moving to Royal Holloway for a PhD in environmental history, is obviously besotted by the clods of earth archaeologists used to regard as nothing more than a barrier between them and their discoveries. He tours his labs, showing off an incredible variety of ways of finding the information hidden in the earth. One room looks like a garden centre: little pots of soil line the shelves, waiting to be injected with resins as hard as Araldyte to turn them into solid blocks. Next, you are in a machine room worthy of a shipyard, where black-oiled machines slowly grind down the soil blocks into 0.075mm thick, transparent cross sections. Then, on to a room that looks like a medical lab, all computers and microscopes and methodically filed slides. Across the way, you enter an altogether more watery environment, where the contents of the mud are sieved out with a gold prospector's care. Next door, the buzzing centrifuges and white coats are more reminiscent of the chemistry lab.

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Branch's challenge is to convince an initial entry of five undergraduates to follow him into this arcane world next September. Their BSc will give them a grounding in other areas of physical geography, but they will spend much of their time in the later stages of their degree in Branch's labs. He hopes to get them working directly on projects in Britain, South America and across Europe that he has developed at Royal Holloway.

His department, like other geography departments across the country, has suffered from falling applications from schools in which the subject has become an increasingly marginal part of the curriculum. This course hopes to exploit the popularity of Time Team and other television archaeology projects to draw students into a deeper study of the subject.

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"I realise that not everyone is going to end up spending their life doing this but it would be nice if I could inspire a few people to investigate what is in the ground and what insights, with proper techniques and analysis, you can get out of it," Branch says. "We need people with a genuine interest in history, but also a strong science background. Whether we will find them, I don't yet know."