Issue 114

Sept / Oct 2010

news

All the latest archaeology news from around the country

features

MAIN FEATURE: Happisburgh

The project leaders give us the latest findings after six years of research on the earliest humans in Britain.

The obscure ownership of archaeological material

Haggai Mor recently worked in one of the world's largest archaeological store and wondered who all the things dug up actaully belong to?

Finding Boudica's Last Battlefield

With the help of computerised terrain analysis, Steve Kaye has narrowed down the possibilities.

The Lost Anglo-Saxon Church of Westbury-on-Trym

Jon Cannon explores a crypt beneath a Bristol church and is greeted with an amazing find.

Finding Private Mather

A victim of battle in WW1 remembered by his family, is finally laid to rest.

Archaeology: What Is It For?

Martin Carver reflects on how and why archaeologists do what we do.

The Varmints Show

In the Varmints' second exploration of music and archaeology, Breck Parkman is uncovering the 'Whitehouse of Hippiedom' at the Olompali State Historic Park, San Francisco.

science

The dark secrets of ancient peat, the decaying of Star Carr

on the web

Audio-visual presentations online and the 'Visual Essays' of ArchAtlas.

Mick's travels

Mick and Jon share the wonders of Jersey

CBA Correspondent

From CBA Publications Officer, Catrina Appleby

letters

Your views and responses

features

THE BIG DIG: Links of Noltland

Eroding sand dunes are revealing an ancient landscape on a windswept and remote Scottish island.

MAIN FEATURE: Digging for (Invisible) People

Eroding sand dunes are revealing an ancient landscape on a windswept and remote Scottish island.

Dig for Shakespeare

Literary critics may wonder if Shakespeare wrote all those plays, but archaeologists know where to find him.

The Varmints Show

An occasional series specifically for the website, showcasing pop music inspired by archaeology or heritage. The first of the series features Air-Raid Shelter (Pillbox) by The Human Cabbages.

More online features to follow

news

All the latest archaeology news from around the country

on the web

Caroline Wickham-Jones investigates real and reconstructed worlds, and Andy Burnham highlights ancient sites viewable from the roadside, including extra content.

letters

Your views and responses

ISSN 1357-4442

Editor Mike Pitts

science

The dark secrets of ancient peat

Is Star Carr decaying, and if so how can we stop it? Sebastian Payne, chief scientist at English Heritage, considers the challenge of deciding what to do about an iconic site.

Excavation reveals, but also destroys – especially, as is so often the case, when time and money are limited. This is why the Valetta Convention (1992) and our planning policies (PPG16 and the new PPS5) all favour preservation in situ when possible. Waterlogged archaeology, however, poses particular problems: preserved when water excludes oxygen, remains are very vulnerable to changes in hydrology. And as waterlogged archaeology is underground, we cannot easily check its condition.

Recent debate about Star Carr on the edge of a now-dry lake in North Yorkshire illustrates these issues. When Grahame Clark first excavated this key early Mesolithic (10,00–8,500BC) site in 1949–51, what was most significant was the quality of organic preservation. In the lower part of the dig, wet lake-edge peats preserved numerous bone points, antler worked by the groove-and-splinter technique, pierced antler frontlets, a brushwood “platform” and part of an oar or paddle. Star Carr raised ideas and questions of wide significance that have been discussed ever since¹.

Excavation by Paul Mellars in the 1980s revealed the site to be more extensive than Clark thought, and uncovered part of a platform or track of aspen planks; preservation, however, was not as good as Clark found². In the past five years, Nicky Milner, Chantal Conneller and Barry Taylor have shown the site to be larger still, and preservation where they have excavated has been even worse – bone in very poor condition (some even reduced to gelatin), antler flattened and worked wood fragments in advanced decay³.

The local water table at Star Carr is maintained by recent rainwater and varies seasonally; it has been lowered by field drains put in some 10 years ago. When water levels fall, oxygen increases and organic remains start to decay, as has been happening in the higher peat. But lower down in some parts of the peat, sulphur, which probably originally comes from the underlying Jurassic marine clays, makes things much worse. In the anoxic waterlogged peats, the sulphur is locked up as reduced sulphides. But when water falls and oxygen rises, the sulphides are locally oxidised producing very acid conditions, which attack antler, bone and wood.

In deciding what to do, there are three key questions. Do parts of Star Carr still preserve important evidence of Mesolithic wood and antler working, and other organic artefacts? If still there, are these remains now decaying rapidly? And can we stop such decay?

Decay rates are very hard to assess for buried deposits. You need to study condition at different points in time, without in the process affecting decay; we have not yet found a good way of doing this. Monitoring reduction potential (or redox potential) of the water in archaeological deposits helps to reveal the current preservation status, but does not give a clear indication of the rate of decay now or in the past.

Can we stop decay by blocking the field drains to raise the local water table? Again, we do not know enough. There is evidence that rewetting can lead to a brief period of rapid damage before conditions stabilise, but how serious this is likely to be, is hard to assess.

It can be salutary to reflect on what we do not know: hopefully this will encourage further research in what is a difficult and interesting subject. But sometimes there is no time for research before decisions have to be made.

Thanks to Nicky Milner, Steve Boreham, Tony Brown and Jonathan Last for information and discussion. The recent Star Carr excavations feature in an excellent 30-minute video by Sarah Senior.

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